Brian_Lee_Static_Routing

Principles of Internetworking

Mohd J Alam; Brian Lee; Aubrey Peloubet; Suraj Bharath Chada

OCTOBER 30, 2014

ECE 5451/6321| Lab #3 Report

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Table of Contents1 Lab Objectives.....................................................................................................................................2

2 Equipment Setup.................................................................................................................................2

2.1 Network Setup.............................................................................................................................3

2.1.1 Configuring PC2 as a Router.................................................................................................4

2.2 Configuring Static Routing Tables for the PCs..............................................................................4

3 Configuring the CISCO Router..............................................................................................................5

3.1 Setting Static Routing Table Entries on Router1..........................................................................5

4 Finalizing and Exploring Router Configuration.....................................................................................6

4.1 Finalizing Network Setup and Testing..........................................................................................6

4.2 Testing Routes with ping.............................................................................................................7

4.3 Observe MAC Addresses at a router............................................................................................8

4.4 Multiple Machines in the Routing Table......................................................................................8

4.5 Default Routes.............................................................................................................................9

5 Observing Proxy ARP.........................................................................................................................10

6 Exploring the Role of Netmasks at Hosts...........................................................................................11

6.1 IP Configuration.........................................................................................................................11

6.2 Routing Configuration................................................................................................................13

6.3 Communication between Routers and Hosts across Different Networks..................................13

6.4 Broadcast Communications between Hosts with Different Netmasks.......................................16

6.5 Routing between Hosts within the same Ethernet Hub.............................................................18

7 Conclusion.........................................................................................................................................21

Appendix – I...............................................................................................................................................22


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1 Lab Objectives- How to turn a computer with multiple interfaces into a router- How to setup static routing on Linux PC router and Cisco Routers- How ICMP messages update routing table entries.- How Proxy ARP helps to connect different networks without reconfiguring the hosts- How to work with different network masks

Note: Though LAB3 instructions suggested using PC3 as a router instead of the PC2 (as stated by the lab manual), we ended up using the PC2 as the router. We began our experiments with PC3 as the router, but the interface eth1 on PC3 had some technical problem and was not functioning properly, so we turned PC2 into the router and completed the experiments.

2 Equipment SetupThree PCs (PC1, PC2, and PC4) are connected with three hubs (HUB1, HUB2, HUB3) and router (RT1) according to Figure 1. PC2 was configured as a router to route traffic between network with HUB1 and HUB2. Details of manually configured routing tables and IP addresses exercises are described the upcoming sections. Table1 shows the IP addresses of the hosts, routers, and the networks.

Figure 1 Network Topology

Table 1 IP addresses for hosts, routers, and networks.

Linux PC Ethernet Interface eth0 Ethernet Interface eth1PC1 10.0.1.11/24 DisabledPC2 10.0.1.21/24 10.0.2.22/24PC4 10.0.3.41/24 Disabled

CISCO Router Ethernet Interface GigabitEthernet0/0 Ethernet Interface GigabitEthernet0/1ROUTER1 10.0.2.1/24 10.0.3.1/24


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2.1 Network SetupIP addresses for PC1, PC2, and PC4 were configured according to Table1 for all outlined interfaces using the sudo ifconfig command. IP addresses to Router1’s interfaces were configured after connecting PC1’s serial interface to the Router’s console interface with the special serial cable and running IOS commands. Communication to the router was established using sudo kermit. Figure2 shows the partial output of the router console commands to show the interfaces configuration.

Figure 2 Router1’s interface configurations.

Wireshark was started with sudo wireshark command. Following ping commands were issued from PC1 while wireshark was set to capture the results.

ping –c 5 10.0.1.21 ping –c 5 10.0.2.1 ping –c 5 10.0.3.41

As expected, only one of the pings (10.0.1.21 or PC2) reached its destination and received replay. PC4 and the Router (10.0.3.41 and 10.0.2.1) were not reachable, and there was no ARP request for these addresses either. The command window displayed destination unreachable. Figure 3displayes the Wireshark captures for the ping.

router1#show interfacesGigabitEthernet0/0 is up, line protocol is up Hardware is CN Gigabit Ethernet, address is 1cdf.0f9a.b1c0 (bia 1cdf.0f9a.b1c0) Description: $ETH-LAN$$ETH-SW-LAUNCH$$INTF-INFO-GE 0/0$ Internet address is 10.0.2.1/24 MTU 1500 bytes, BW 10000 Kbit/sec, DLY 1000 usec, reliability 255/255, txload 1/255, rxload 1/255 Encapsulation ARPA, loopback not set Keepalive set (10 sec) Half-duplex, 10Mb/s, media type is RJ45 GigabitEthernet0/1 is up, line protocol is up Hardware is CN Gigabit Ethernet, address is 1cdf.0f9a.b1c1 (bia 1cdf.0f9a.b1c1) Internet address is 10.0.3.1/24 MTU 1500 bytes, BW 10000 Kbit/sec, DLY 1000 usec, reliability 255/255, txload 1/255, rxload 1/255 Encapsulation ARPA, loopback not set Keepalive set (10 sec) Half-duplex, 10Mb/s, media type is RJ45


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Figure 3 Wireshark captures of the ping commands (Network Configured without any routing table)

2.1.1 Configuring PC2 as a Router PC2 was configured as a router first by enabling the IP forwarding with the following command:

echo 1 | sudo tee -a /proc/sys/net/ipv4/ip_forward

2.2 Configuring Static Routing Tables for the PCsRouting table of PC1 and PC4 are configured as they are hosts. PC2’s routing table was configured as a router. All routing table configurations were completed using Linux static route commands. Figure 4, Figure 5, and Figure 6 shows the configured routing tables for PC1, PC2, and PC4 as captured from the command terminal.

Figure 4 PC1 Routing Table

There are three entries in PC1 routing table. First entry is for the local network (10.0.1.0) of PC1, hence no gateway or next hop. 2nd entry (10.0.2.0/24) for the intermediate network (NET2) between the PC2 router and Router1 which has the next hop of 10.0.1.21, and the 3rd entry (10.0.3.0/24) is for the network (NET3) of PC4 with the same gateway address. All of the entries have interface of eth0 since this is the only interface of the host PC1 to its network.

[teluser@telecomm05 ~]$ netstat -rnKernel IP routing tableDestination Gateway Genmask Flags MSS Window irtt Iface10.0.1.0 0.0.0.0 255.255.255.0 U 0 0 0 eth010.0.2.0 10.0.1.21 255.255.255.0 UG 0 0 0 eth010.0.3.0 10.0.1.21 255.255.255.0 UG 0 0 0 eth0[teluser@telecomm05 ~]$


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There are three entries in PC2 routing table. First entry (10.0.1.0/24) is for the network NET1 of PC1 with interface eth0. It is local to PC2, hence no gateway or next hop. Second entry (10.0.2.0/24) is for the intermediate network (NET2) between the PC2 router and Router1 which is also local to PC2 but on interface eth1. Third entry (10.0.3.0/24) is for the network (NET3) of PC4 with the same gateway address of Router1’s GigabitEthernet0/0 interface address (10.0.2.1), and it is accessed through interface eth1 of PC2.


There are three entries in PC4 routing table. First entry (10.0.1.0/24) is for the network NET1 of PC1 with interface eth0 via Router1 (10.0.3.1). Second entry (10.0.2.0/24) is for the intermediate network (NET2) between the Router1 router and PC2. It has the same next hop address as the previous entry. Third entry (10.0.3.0/24) is for the network (NET3) of PC4 which is local and thus no next hop address. All of the entries have interface of eth0 since this is the only interface of the host PC4 to its network.

3 Configuring the CISCO RouterCisco router (Router1) was configured following instructions and commands from the lab manual according to IP address assignment in Table1. Appendix –A has the configuration output extracted from the IOS terminal after issuing the following commands:

Show interfacesShow running-config

[See Appendix-A for the output]

3.1 Setting Static Routing Table Entries on Router1Router1 ones static routing table was examined before making any changes to it. Initial routing table of Router1 was examined by issuing show ip route command on the IOS terminal. Figure 7 shows the initial routing table before any entry was made to the table.

[teluser@TeleComm07 ~]$ netstat -rnKernel IP routing tableDestination Gateway Genmask Flags MSS Window irtt Iface10.0.1.0 0.0.0.0 255.255.255.0 U 0 0 0 eth010.0.2.0 0.0.0.0 255.255.255.0 U 0 0 0 eth110.0.3.0 10.0.2.1 255.255.255.0 UG 0 0 0 eth1[teluser@TeleComm07 ~]$

[teluser@TeleComm08 ~]$ route -eKernel IP routing tableDestination Gateway Genmask Flags MSS Window irtt Iface10.0.1.0 10.0.3.1 255.255.255.0 UG 0 0 0 eth010.0.2.0 10.0.3.1 255.255.255.0 UG 0 0 0 eth010.0.3.0 * 255.255.255.0 U 0 0 0 eth0[teluser@TeleComm08 ~]$


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Figure 7 Router1 routing table before static entry.

Static route entry was made into Router1’s routing table using the ip route commands. Figure 8 shows final routing table for the Cisco router. Static entry is identified with an “S” on the very left of the entry. In this table we have one static entry for the NET1 (10.0.1.0/24) via PC2 router 10.0.2.22. NET2 and NET3 are directly connected to Router1’s GigabitEthernet0/0 and GigabitEthernet0/1 interface directly (indicated by “L” for local).

Figure 8 Router1 routing table after static entries.

4 Finalizing and Exploring Router Configuration

4.1 Finalizing Network Setup and TestingNetwork was tested for correct configuration by successfully by issuing ping commands from each host and router to every other host and router. All ping commands were successful across the network.

router1#show ip route Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGP D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2 E1 - OSPF external type 1, E2 - OSPF external type 2 i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2 ia - IS-IS inter area, * - candidate default, U - per-user static route o - ODR, P - periodic downloaded static route, + - replicated route

Gateway of last resort is not set

10.0.0.0/8 is variably subnetted, 4 subnets, 2 masksC 10.0.2.0/24 is directly connected, GigabitEthernet0/0L 10.0.2.1/32 is directly connected, GigabitEthernet0/0C 10.0.3.0/24 is directly connected, GigabitEthernet0/1L 10.0.3.1/32 is directly connected, GigabitEthernet0/1router1#

router1#show ip routeCodes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGP D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2 E1 - OSPF external type 1, E2 - OSPF external type 2 i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2 ia - IS-IS inter area, * - candidate default, U - per-user static route o - ODR, P - periodic downloaded static route, + - replicated route


10.0.0.0/8 is variably subnetted, 5 subnets, 2 masksS 10.0.1.0/24 [1/0] via 10.0.2.22C 10.0.2.0/24 is directly connected, GigabitEthernet0/0L 10.0.2.1/32 is directly connected, GigabitEthernet0/0C 10.0.3.0/24 is directly connected, GigabitEthernet0/1L 10.0.3.1/32 is directly connected, GigabitEthernet0/1router1#


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4.2 Testing Routes with pingWireshark session started at PC1 while command ping was issued from PC1 to PC4. Routing table of each hosts and router are saved after the ping command:

ping –c 5 10.0.2.1

The Wireshark captures seen by PC1 are shown in Figure 9.

Figure 9: PC1 Wireshark Output

Figures 10, 11, 12 and 13 show the routing tables for each host after the ping:

Figure 10 PC1 Routing Table after ping


Figure 12 Router1’s Routing Table after ping

Note that Router1’s routing table shows that network 10.0.1.0 can be reached through PC2.

No. Time Source Destination Protocol Info 1 0.000000 10.0.1.11 10.0.3.41 ICMP Echo (ping) request 2 0.001908 10.0.3.41 10.0.1.11 ICMP Echo (ping) reply 3 1.001184 10.0.1.11 10.0.3.41 ICMP Echo (ping) request 4 1.002182 10.0.3.41 10.0.1.11 ICMP Echo (ping) reply 5 5.000853 Dell_22:0d:4b Dell_22:2b:29 ARP Who has 10.0.1.11? Tell 10.0.1.21 6 5.000879 Dell_22:2b:29 Dell_22:0d:4b ARP 10.0.1.11 is at 00:1a:a0:22:2b:29

[teluser@telecomm05 ~]$ sudo routeKernel IP routing tableDestination Gateway Genmask Flags Metric Ref Use Iface10.0.1.0 * 255.255.255.0 U 0 0 0 eth010.0.2.0 10.0.1.21 255.255.255.0 UG 0 0 0 eth010.0.3.0 10.0.1.21 255.255.255.0 UG 0 0 0 eth0192.168.122.0 * 255.255.255.0 U 0 0 0 virbr0

[teluser@TeleComm06 ~]$ sudo routeKernel IP routing tableDestination Gateway Genmask Flags Metric Ref Use Iface10.0.1.0 * 255.255.255.0 U 0 0 0 eth010.0.2.0 * 255.255.255.0 U 0 0 0 eth110.0.3.0 10.0.2.1 255.255.255.0 UG 0 0 0 eth1[teluser@TeleComm06 ~]$

router1#show ip routeCodes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGP D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2 E1 - OSPF external type 1, E2 - OSPF external type 2 i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2 ia - IS-IS inter area, * - candidate default, U - per-user static route o - ODR, P - periodic downloaded static route, + - replicated route


10.0.0.0/8 is variably subnetted, 5 subnets, 2 masksS 10.0.1.0/24 [1/0] via 10.0.2.22C 10.0.2.0/24 is directly connected, GigabitEthernet0/0L 10.0.2.1/32 is directly connected, GigabitEthernet0/0C 10.0.3.0/24 is directly connected, GigabitEthernet0/1L 10.0.3.1/32 is directly connected, GigabitEthernet0/1


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4.3 Observe MAC Addresses at a routerAll ARP entries were cleared from PC1, PC2, PC4, and Router1. Wireshark session was started on PC1 for interface eth0 and on PC4 for eth0 interface. A ping command was issued from PC1 to PC4 with the following command:

Ping –c 5 10.0.3.41

Figure 14 PC1 Wireshark capture of ping


The source and destination addresses in the Ethernet headers belong to only hosts within the network and changes as it gets passed through the router, while the IP source and destination addresses in the IP header stay the same along the entire transport.

4.4 Multiple Machines in the Routing TableIn order to understand how an IP router or Linux PC resolve multiple matching entries in a routing table, we added nonexistent gateways to PC1’s routing tables.

We then issued the following ping commands to see how the network would react.

Ping –c 1 10.0.3.9

[teluser@TeleComm08 ~]$ sudo routeKernel IP routing tableDestination Gateway Genmask Flags Metric Ref Use Iface10.0.1.0 10.0.3.1 255.255.255.0 UG 0 0 0 eth010.0.2.0 10.0.3.1 255.255.255.0 UG 0 0 0 eth010.0.3.0 * 255.255.255.0 U 0 0 0 eth0[teluser@TeleComm08 ~]$

No. Time Source Destination Protocol Info 1 0.000000 Dell_22:2b:29 Broadcast ARP Who has 10.0.1.21? Tell 10.0.1.11 2 0.000303 Dell_22:0d:4b Dell_22:2b:29 ARP 10.0.1.21 is at 00:1a:a0:22:0d:4b 3 0.000342 10.0.1.11 10.0.3.41 ICMP Echo (ping) request 4 0.003441 10.0.3.41 10.0.1.11 ICMP Echo (ping) reply 5 1.001785 10.0.1.11 10.0.3.41 ICMP Echo (ping) request 6 1.002830 10.0.3.41 10.0.1.11 ICMP Echo (ping) reply 7 2.003048 10.0.1.11 10.0.3.41 ICMP Echo (ping) request 8 2.004103 10.0.3.41 10.0.1.11 ICMP Echo (ping) reply 9 3.004384 10.0.1.11 10.0.3.41 ICMP Echo (ping) request 10 3.005430 10.0.3.41 10.0.1.11 ICMP Echo (ping) reply 11 4.005664 10.0.1.11 10.0.3.41 ICMP Echo (ping) request 12 4.006720 10.0.3.41 10.0.1.11 ICMP Echo (ping) reply 13 5.002522 Dell_22:0d:4b Dell_22:2b:29 ARP Who has 10.0.1.11? Tell 10.0.1.21 14 5.002585 Dell_22:2b:29 Dell_22:0d:4b ARP 10.0.1.11 is at 00:1a:a0:22:2b:29

No. Time Source Destination Protocol Info 114 953.491484 10.0.1.11 10.0.3.41 ICMP Echo (ping) request 115 953.491671 Dell_20:67:71 Broadcast ARP Who has 10.0.3.1? Tell 10.0.3.41 116 953.492036 Cisco_9a:b1:c1 Dell_20:67:71 ARP 10.0.3.1 is at 1c:df:0f:9a:b1:c1 117 953.492054 10.0.3.41 10.0.1.11 ICMP Echo (ping) reply 118 954.491399 10.0.1.11 10.0.3.41 ICMP Echo (ping) request 119 954.491446 10.0.3.41 10.0.1.11 ICMP Echo (ping) reply 120 955.492633 10.0.1.11 10.0.3.41 ICMP Echo (ping) request 121 955.492681 10.0.3.41 10.0.1.11 ICMP Echo (ping) reply 122 956.493943 10.0.1.11 10.0.3.41 ICMP Echo (ping) request 123 956.493988 10.0.3.41 10.0.1.11 ICMP Echo (ping) reply 124 957.495197 10.0.1.11 10.0.3.41 ICMP Echo (ping) request 125 957.495246 10.0.3.41 10.0.1.11 ICMP Echo (ping) reply


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Ping –c 1 10.0.3.14

Ping –c 1 10.0.4.1

Figures 16 shows the routing table for PC1 after the ping.

Figure 17 shows the Wireshark captures seen by PC1.


Note that the nonexistent gateways have a higher prefix length and are above the original working routing entries.


The Wireshark captures tell us that PC1 does not know that these gateways are missing and chose to use the nonexistent gateways instead of the working gateways. Figure 17 shows that PC1 requested three times for a MAC address from these gateways before moving on to the next ping. When setting up routing tables with multiple entries for the same network, those with a higher prefix length maintain priority.

4.5 Default RoutesWe deleted the nonexistent gateways from PC1’s routing table and added a routing entry for a 10.0.10.0 network with PC2 as the gateway. We also added a similar entry for the same network into PC2’s routing table with Router1 as its gateway. We then issued the following ping command to see how the packet will be moved around the network.

Ping –c 5 10.0.10.110

[teluser@telecomm05 ~]$ sudo routeKernel IP routing tableDestination Gateway Genmask Flags Metric Ref Use Iface10.0.3.9 10.0.1.81 255.255.255.255 UGH 0 0 0 eth010.0.1.0 * 255.255.255.0 U 0 0 0 eth010.0.2.0 10.0.1.21 255.255.255.0 UG 0 0 0 eth010.0.3.0 10.0.1.61 255.255.255.0 UG 0 0 0 eth010.0.3.0 10.0.1.21 255.255.255.0 UG 0 0 0 eth0192.168.122.0 * 255.255.255.0 U 0 0 0 virbr010.0.0.0 10.0.1.71 255.255.0.0 UG 0 0 0 eth0[teluser@telecomm05 ~]$

No. Time Source Destination Protocol Info 1 0.000000 Dell_22:2b:29 Broadcast ARP Who has 10.0.1.81? Tell 10.0.1.11 2 0.999990 Dell_22:2b:29 Broadcast ARP Who has 10.0.1.81? Tell 10.0.1.11 3 1.999993 Dell_22:2b:29 Broadcast ARP Who has 10.0.1.81? Tell 10.0.1.11 4 13.400000 Dell_22:2b:29 Broadcast ARP Who has 10.0.1.61? Tell 10.0.1.11 5 14.399994 Dell_22:2b:29 Broadcast ARP Who has 10.0.1.61? Tell 10.0.1.11 6 15.399990 Dell_22:2b:29 Broadcast ARP Who has 10.0.1.61? Tell 10.0.1.11 7 24.752238 Dell_22:2b:29 Broadcast ARP Who has 10.0.1.71? Tell 10.0.1.11 8 25.752238 Dell_22:2b:29 Broadcast ARP Who has 10.0.1.71? Tell 10.0.1.11 9 26.752240 Dell_22:2b:29 Broadcast ARP Who has 10.0.1.71? Tell 10.0.1.11


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Figure 19 PC2 eth0 Wireshark capture of ping


PC1 sees that it cannot reach 10.0.10.110. The ICMP Echo Request message traveled all the way to Router1 where it then stopped. The time between Echo requests and replies seen by PC1 is nearly 2ms while the time seen by PC2 on eth1 is 5 times faster at 0.4ms. We can safely assume that this means Router1 did not see this network in its routing table and responded with Destination Unreachable.

5 Observing Proxy ARPWe want to see how Proxy ARP would work when a router is given traffic outside of its routing table.

We set PC4’s netmask to 255.0.0.0 so it would assume it belongs to a different network and issued the following ping from PC4 to PC1 to see how the network would react.

ping –c 2 10.0.1.11

No. Time Source Destination Protocol Info 1 0.000000 Dell_22:2b:29 Broadcast ARP Who has 10.0.1.21? Tell 10.0.1.11 2 0.000322 Dell_22:0d:4b Dell_22:2b:29 ARP 10.0.1.21 is at 00:1a:a0:22:0d:4b 3 0.000362 10.0.1.11 10.0.10.110 ICMP Echo (ping) request 4 0.002259 10.0.2.1 10.0.1.11 ICMP Destination unreachable (Host unreachable) 5 1.000622 10.0.1.11 10.0.10.110 ICMP Echo (ping) request 6 1.001435 10.0.2.1 10.0.1.11 ICMP Destination unreachable (Host unreachable) 7 2.001777 10.0.1.11 10.0.10.110 ICMP Echo (ping) request 8 2.002512 10.0.2.1 10.0.1.11 ICMP Destination unreachable (Host unreachable) 9 3.002822 10.0.1.11 10.0.10.110 ICMP Echo (ping) request 10 3.003597 10.0.2.1 10.0.1.11 ICMP Destination unreachable (Host unreachable) 11 4.003893 10.0.1.11 10.0.10.110 ICMP Echo (ping) request 12 4.004670 10.0.2.1 10.0.1.11 ICMP Destination unreachable (Host unreachable) 13 5.002091 Dell_22:0d:4b Dell_22:2b:29 ARP Who has 10.0.1.11? Tell 10.0.1.21 14 5.002134 Dell_22:2b:29 Dell_22:0d:4b ARP 10.0.1.11 is at 00:1a:a0:22:2b:29

No. Time Source Destination Protocol Info 1 0.000000 Dell_22:2b:29 Broadcast ARP Who has 10.0.1.21? Tell 10.0.1.11 2 0.000056 Dell_22:0d:4b Dell_22:2b:29 ARP 10.0.1.21 is at 00:1a:a0:22:0d:4b 3 0.000370 10.0.1.11 10.0.10.110 ICMP Echo (ping) request 4 0.001992 10.0.2.1 10.0.1.11 ICMP Destination unreachable (Host unreachable) 5 1.000675 10.0.1.11 10.0.10.110 ICMP Echo (ping) request 6 1.001172 10.0.2.1 10.0.1.11 ICMP Destination unreachable (Host unreachable) 7 2.001819 10.0.1.11 10.0.10.110 ICMP Echo (ping) request 8 2.002262 10.0.2.1 10.0.1.11 ICMP Destination unreachable (Host unreachable) 9 3.002892 10.0.1.11 10.0.10.110 ICMP Echo (ping) request 10 3.003356 10.0.2.1 10.0.1.11 ICMP Destination unreachable (Host unreachable) 11 4.003978 10.0.1.11 10.0.10.110 ICMP Echo (ping) request 12 4.004440 10.0.2.1 10.0.1.11 ICMP Destination unreachable (Host unreachable) 13 5.001849 Dell_22:0d:4b Dell_22:2b:29 ARP Who has 10.0.1.11? Tell 10.0.1.21 14 5.002157 Dell_22:2b:29 Dell_22:0d:4b ARP 10.0.1.11 is at 00:1a:a0:22:2b:29

No. Time Source Destination Protocol Info 1 0.000000 Kingston_6a:c0:30 Broadcast ARP Who has 10.0.2.1? Tell 10.0.2.22 2 0.000600 Cisco_9a:b1:c0 Kingston_6a:c0:30 ARP 10.0.2.1 is at 1c:df:0f:9a:b1:c0 3 0.000621 10.0.1.11 10.0.10.110 ICMP Echo (ping) request 4 0.001098 10.0.2.1 10.0.1.11 ICMP Destination unreachable (Host unreachable) 6 0.999832 10.0.1.11 10.0.10.110 ICMP Echo (ping) request 7 1.000287 10.0.2.1 10.0.1.11 ICMP Destination unreachable (Host unreachable) 8 2.000958 10.0.1.11 10.0.10.110 ICMP Echo (ping) request 9 2.001379 10.0.2.1 10.0.1.11 ICMP Destination unreachable (Host unreachable) 10 3.002045 10.0.1.11 10.0.10.110 ICMP Echo (ping) request 11 3.002471 10.0.2.1 10.0.1.11 ICMP Destination unreachable (Host unreachable) 12 4.003131 10.0.1.11 10.0.10.110 ICMP Echo (ping) request 13 4.003556 10.0.2.1 10.0.1.11 ICMP Destination unreachable (Host unreachable)


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Figure 21 PC4 ARP Table after ping




We can see from the Wireshark outputs that Router1 is responding to PC4’s ARP request for PC1 and has provided its own MAC address to PC4 for PC1. Should we check the ARP, we would find that 10.0.1.11 has Router1’s MAC address. With Proxy-ARP disabled, Router1 would have simply performed traditional routing.

[teluser@TeleComm08 ~]$ sudo arp -a? (10.0.1.11) at 1c:df:0f:9a:b1:c1 [ether] on eth0[teluser@TeleComm08 ~]$

No. Time Source Destination Protocol Info 1 0.000000 10.0.3.41 10.0.1.11 ICMP Echo (ping) request 2 0.000145 10.0.1.11 10.0.3.41 ICMP Echo (ping) reply 3 1.000098 10.0.3.41 10.0.1.11 ICMP Echo (ping) request 4 1.000141 10.0.1.11 10.0.3.41 ICMP Echo (ping) reply 5 4.999143 Dell_22:2b:29 Dell_22:0d:4b ARP Who has 10.0.1.21? Tell 10.0.1.11 6 4.999416 Dell_22:0d:4b Dell_22:2b:29 ARP 10.0.1.21 is at 00:1a:a0:22:0d:4b

No. Time Source Destination Protocol Info 8 55.507724 10.0.3.41 10.0.1.11 ICMP Echo (ping) request 9 55.508547 Kingston_6a:c0:30 Broadcast ARP Who has 10.0.2.1? Tell 10.0.2.22 10 55.508898 Cisco_9a:b1:c0 Kingston_6a:c0:30 ARP 10.0.2.1 is at 1c:df:0f:9a:b1:c0 11 55.508919 10.0.1.11 10.0.3.41 ICMP Echo (ping) reply 12 56.507870 10.0.3.41 10.0.1.11 ICMP Echo (ping) request 13 56.508244 10.0.1.11 10.0.3.41 ICMP Echo (ping) reply

No. Time Source Destination Protocol Info 10 75.505161 Dell_20:67:71 Broadcast ARP Who has 10.0.1.11? Tell 10.0.3.41 11 75.505719 Cisco_9a:b1:c1 Dell_20:67:71 ARP 10.0.1.11 is at 1c:df:0f:9a:b1:c1 12 75.505738 10.0.3.41 10.0.1.11 ICMP Echo (ping) request 13 75.507634 10.0.1.11 10.0.3.41 ICMP Echo (ping) reply 14 76.505833 10.0.3.41 10.0.1.11 ICMP Echo (ping) request 15 76.506924 10.0.1.11 10.0.3.41 ICMP Echo (ping) reply


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6 Exploring the Role of Netmasks at Hosts

6.1 IP ConfigurationIn this exercise, we explored how hosts that are connected to the same local area network, but have different netmasks, communicate or fail to communicate. We configured the hosts and the router to conform to the topology shown in Figure 9 using the IP addresses given in Table 2.

Figure 9: Network topology for Exercise 7

Table 2: IP addresses for Exercise 7Linux PC Ethernet Interface eth0 Ethernet Interface eth1PC1 10.0.1.10 /24 DisabledPC2 10.0.2.10 /24 DisabledPC3 10.0.2.137 /29 DisabledPC4 10.0.2.139 /24 DisabledCISCO Router Ethernet Interface GigabitEthernet0/0 Ethernet Interface GigabitEthernet0/1ROUTER1 10.0.2.1/24 10.0.3.1/24


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6.2 Routing ConfigurationNote that PC2, PC3, and PC4 have different netmasks. Here, each host has only a default route. In other words, the routing table at a host know only about the directly connected networks and the default gateway.

We added Router1 as the default gateway on all hosts using the following commands:

PC1% route add –net 10.0.2.0 netmask 255.255.255.0 gw 10.0.2.138PC2% route add –net 10.0.1.0 netmask 255.255.255.0 gw 10.0.2.138PC3% route add –net 10.0.1.0 netmask 255.255.255.0 gw 10.0.2.138PC3% route add –net 10.0.2.0 netmask 255.255.255.0 gw 10.0.2.138PC4% route add –net 10.0.1.0 netmask 255.255.255.0 gw 10.0.2.138

Note that PC3 needs an additional router gateway to its own Ethernet hub. This is because PC3 sees itself as a /29 IP address within a /24 world and will not broadcast to hosts outside of its subnet.

6.3 Communication between Routers and Hosts across Different NetworksIn order to test the network’s connections, we issued ping commands from PC1 to PC2 and PC3 using the following commands:

PC1% ping –c 2 10.0.2.10PC1% ping –c 2 10.0.2.137

We captured the filtered ICMP and ARP packets through Wireshark in both PC1 and PC4.

Figures 10, 11, 12, and 13 show the ARP table, routing table, and routing cache of each host before issuing the ping commands.

Figure 10: ARP table, routing table, and routing cache of PC1 before issuing ping

[teluser@telecomm05 ~]$ sudo arp -a[teluser@telecomm05 ~]$ sudo netstat -rnKernel IP routing tableDestination Gateway Genmask Flags MSS Window irtt Iface10.0.1.0 0.0.0.0 255.255.255.0 U 0 0 0 eth010.0.2.0 10.0.1.1 255.255.255.0 UG 0 0 0 eth0192.168.122.0 0.0.0.0 255.255.255.0 U 0 0 0 virbr0[teluser@telecomm05 ~]$ sudo route -CKernel IP routing cacheSource Destination Gateway Flags Metric Ref Use Iface* 224.0.0.1 224.0.0.1 ml 0 0 0 lo[teluser@telecomm05 ~]$


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Figures 14, 15, 16, and 17 show the ARP table, routing table, and routing cache of each host after issuing the ping commands.

Figure 14: ARP table, routing table, and routing cache of PC1 after issuing ping

[teluser@TeleComm06 ~]$ sudo arp -a[teluser@TeleComm06 ~]$ sudo netstat -rnKernel IP routing tableDestination Gateway Genmask Flags MSS Window irtt Iface10.0.1.0 10.0.2.138 255.255.255.0 UG 0 0 0 eth010.0.2.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0[teluser@TeleComm06 ~]$ sudo route -CKernel IP routing cacheSource Destination Gateway Flags Metric Ref Use Iface[teluser@TeleComm06 ~]$

[teluser@TeleComm07 ~]$ sudo arp -a[teluser@TeleComm07 ~]$ sudo netstat -rnKernel IP routing tableDestination Gateway Genmask Flags MSS Window irtt Iface10.0.2.136 0.0.0.0 255.255.255.248 U 0 0 0 eth010.0.1.0 10.0.2.138 255.255.255.0 UG 0 0 0 eth010.0.2.0 10.0.2.138 255.255.255.0 UG 0 0 0 eth0[teluser@TeleComm07 ~]$ sudo route -CKernel IP routing cacheSource Destination Gateway Flags Metric Ref Use Iface[teluser@TeleComm07 ~]$


[teluser@telecomm05 ~]$ sudo arp -a? (10.0.1.1) at 1c:df:0f:9a:b1:c0 [ether] on eth0[teluser@telecomm05 ~]$ sudo netstat -rnKernel IP routing tableDestination Gateway Genmask Flags MSS Window irtt Iface10.0.1.0 0.0.0.0 255.255.255.0 U 0 0 0 eth010.0.2.0 10.0.1.1 255.255.255.0 UG 0 0 0 eth0192.168.122.0 0.0.0.0 255.255.255.0 U 0 0 0 virbr0[teluser@telecomm05 ~]$ sudo route -CKernel IP routing cacheSource Destination Gateway Flags Metric Ref Use Iface* 224.0.0.1 224.0.0.1 ml 0 0 0 lo[teluser@telecomm05 ~]$


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Figure 18 shows the output of the ping command at PC1

[teluser@TeleComm06 ~]$ sudo arp -a? (10.0.2.138) at 1c:df:0f:9a:b1:c1 [ether] on eth0[teluser@TeleComm06 ~]$ sudo netstat -rnKernel IP routing tableDestination Gateway Genmask Flags MSS Window irtt Iface10.0.1.0 10.0.2.138 255.255.255.0 UG 0 0 0 eth010.0.2.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0[teluser@TeleComm06 ~]$ sudo route -CKernel IP routing cacheSource Destination Gateway Flags Metric Ref Use Iface10.0.1.10 10.0.2.10 10.0.2.10 l 0 0 3 lo10.0.2.10 10.0.1.10 10.0.2.138 0 0 3 eth0[teluser@TeleComm06 ~]$

[teluser@TeleComm07 ~]$ sudo arp -a? (10.0.2.138) at 1c:df:0f:9a:b1:c1 [ether] on eth0[teluser@TeleComm07 ~]$ sudo netstat -rnKernel IP routing tableDestination Gateway Genmask Flags MSS Window irtt Iface10.0.2.136 0.0.0.0 255.255.255.248 U 0 0 0 eth010.0.1.0 10.0.2.138 255.255.255.0 UG 0 0 0 eth010.0.2.0 10.0.2.138 255.255.255.0 UG 0 0 0 eth0[teluser@TeleComm07 ~]$ sudo route -CKernel IP routing cacheSource Destination Gateway Flags Metric Ref Use Iface10.0.1.10 10.0.2.137 10.0.2.137 l 0 0 1 lo10.0.2.137 10.0.1.10 10.0.2.138 0 0 1 eth0[teluser@TeleComm07 ~]$

[teluser@TeleComm08 ~]$ sudo arp -a[teluser@TeleComm08 ~]$ sudo netstat -rnKernel IP routing tableDestination Gateway Genmask Flags MSS Window irtt Iface10.0.1.0 10.0.2.138 255.255.255.0 UG 0 0 0 eth010.0.2.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0[teluser@TeleComm08 ~]$ sudo route -CKernel IP routing cacheSource Destination Gateway Flags Metric Ref Use Iface10.0.2.139 10.0.2.138 10.0.2.138 0 0 0 eth0[teluser@TeleComm08 ~]$


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Figure 18: Ping statistics going from PC1 to PC2

Figure 19 and 20 show the Wireshark output on PC1 and PC4.

Figure 19: Wireshark captures seen from PC1 using ICMP and ARP display filters


PC1 cannot see the routing conversation within the 10.0.2.0 network and only sees the requests and replies. PC4 sees the conversation between the router and PC2 because it’s in network 10.0.2.0.

6.4 Broadcast Communications between Hosts with Different NetmasksTo understand how netmasks affect routing, we cleared the ARP table on all hosts and issued a ping command from PC3 to PC4 using the following command:

PC3% ping –c 3 10.0.2.139

We captured the filtered ICMP and ARP packets through Wireshark in PC3.

[teluser@telecomm05 ~]$ sudo ping -c 2 10.0.2.10PING 10.0.2.10 (10.0.2.10) 56(84) bytes of data.64 bytes from 10.0.2.10: icmp_seq=1 ttl=63 time=1.96 ms64 bytes from 10.0.2.10: icmp_seq=2 ttl=63 time=0.776 ms

--- 10.0.2.10 ping statistics ---2 packets transmitted, 2 received, 0% packet loss, time 1002msrtt min/avg/max/mdev = 0.776/1.372/1.969/0.597 ms[teluser@telecomm05 ~]$ sudo ping -c 2 10.0.2.137PING 10.0.2.137 (10.0.2.137) 56(84) bytes of data.64 bytes from 10.0.2.137: icmp_seq=1 ttl=63 time=2.11 ms64 bytes from 10.0.2.137: icmp_seq=2 ttl=63 time=0.790 ms

--- 10.0.2.137 ping statistics ---2 packets transmitted, 2 received, 0% packet loss, time 1002msrtt min/avg/max/mdev = 0.790/1.451/2.113/0.662 ms

No. Time Source Destination Protocol Info 2 8.513535 10.0.1.10 10.0.2.10 ICMP Echo (ping) request 3 8.515467 10.0.2.10 10.0.1.10 ICMP Echo (ping) reply 4 9.514634 10.0.1.10 10.0.2.10 ICMP Echo (ping) request 5 9.515351 10.0.2.10 10.0.1.10 ICMP Echo (ping) reply 9 30.295218 10.0.1.10 10.0.2.137 ICMP Echo (ping) request 10 30.297187 10.0.2.137 10.0.1.10 ICMP Echo (ping) reply 11 31.296426 10.0.1.10 10.0.2.137 ICMP Echo (ping) request 12 31.297147 10.0.2.137 10.0.1.10 ICMP Echo (ping) reply

No. Time Source Destination Protocol Info 7 47.858673 10.0.1.10 10.0.2.10 ICMP Echo (ping) request 8 47.859524 Dell_22:0d:4b Broadcast ARP Who has 10.0.2.138? Tell 10.0.2.10 9 47.859857 Cisco_9a:b1:c1 Dell_22:0d:4b ARP 10.0.2.138 is at 1c:df:0f:9a:b1:c1 10 47.860002 10.0.2.10 10.0.1.10 ICMP Echo (ping) reply 11 48.859732 10.0.1.10 10.0.2.10 ICMP Echo (ping) request 12 48.859851 10.0.2.10 10.0.1.10 ICMP Echo (ping) reply 16 69.639747 10.0.1.10 10.0.2.137 ICMP Echo (ping) request 17 69.640635 Dell_20:6e:bd Broadcast ARP Who has 10.0.2.138? Tell 10.0.2.137 18 69.640949 Cisco_9a:b1:c1 Dell_20:6e:bd ARP 10.0.2.138 is at 1c:df:0f:9a:b1:c1 19 69.641094 10.0.2.137 10.0.1.10 ICMP Echo (ping) reply 21 70.640912 10.0.1.10 10.0.2.137 ICMP Echo (ping) request 22 70.641035 10.0.2.137 10.0.1.10 ICMP Echo (ping) reply


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Figures 21, 22, 23, and 24 show the ARP table, routing table, and routing cache of each host before issuing the ping commands. Note that they are the same as the previous table entries in Tables 10, 11, 12, and 13.





[teluser@telecomm05 ~]$ sudo arp -a[teluser@telecomm05 ~]$ sudo netstat -rnKernel IP routing tableDestination Gateway Genmask Flags MSS Window irtt Iface10.0.1.0 0.0.0.0 255.255.255.0 U 0 0 0 eth010.0.2.0 10.0.1.1 255.255.255.0 UG 0 0 0 eth0192.168.122.0 0.0.0.0 255.255.255.0 U 0 0 0 virbr0[teluser@telecomm05 ~]$ sudo route -CKernel IP routing cacheSource Destination Gateway Flags Metric Ref Use Iface* 224.0.0.1 224.0.0.1 ml 0 0 0 lo[teluser@telecomm05 ~]$


[teluser@TeleComm07 ~]$ sudo arp -a[teluser@TeleComm07 ~]$ sudo netstat -rnKernel IP routing tableDestination Gateway Genmask Flags MSS Window irtt Iface10.0.2.136 0.0.0.0 255.255.255.248 U 0 0 0 eth010.0.1.0 10.0.2.138 255.255.255.0 UG 0 0 0 eth010.0.2.0 10.0.2.138 255.255.255.0 UG 0 0 0 eth0[teluser@TeleComm07 ~]$ sudo route -CKernel IP routing cacheSource Destination Gateway Flags Metric Ref Use Iface[teluser@TeleComm07 ~]$



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Figures 25 shows the ARP table, routing table, and routing cache of PC3 after issuing the ping command.




Figure 27 shows the Wireshark output on PC3


PC3 performs a broadcast because it sees PC4 within its own ‘/29’ subnet, even though PC4 uses a ‘/24’ netmask. PC3 does not require any routing to communicate with PC4.

6.5 Routing between Hosts within the same Ethernet HubWe then explored how PC3 would be able to communicate to PC2. We waited until all the ARP tables cleared and issued a ping from PC3 to PC2 using the command:

PC3% ping –c 3 10.0.2.10

We captured the filtered ICMP and ARP packets through Wireshark in PC3.

[teluser@TeleComm07 ~]$ sudo arp -a? (10.0.2.139) at 00:1a:a0:20:67:71 [ether] on eth0[teluser@TeleComm07 ~]$ sudo routeKernel IP routing tableDestination Gateway Genmask Flags Metric Ref Use Iface10.0.2.136 * 255.255.255.248 U 0 0 0 eth010.0.1.0 10.0.2.138 255.255.255.0 UG 0 0 0 eth010.0.2.0 10.0.2.138 255.255.255.0 UG 0 0 0 eth0[teluser@TeleComm07 ~]$ sudo route -CKernel IP routing cacheSource Destination Gateway Flags Metric Ref Use Iface[teluser@TeleComm07 ~]$

[teluser@TeleComm07 ~]$ sudo ping -c 3 10.0.2.139PING 10.0.2.139 (10.0.2.139) 56(84) bytes of data.64 bytes from 10.0.2.139: icmp_seq=1 ttl=64 time=1.26 ms64 bytes from 10.0.2.139: icmp_seq=2 ttl=64 time=0.422 ms64 bytes from 10.0.2.139: icmp_seq=3 ttl=64 time=0.416 ms

--- 10.0.2.139 ping statistics ---3 packets transmitted, 3 received, 0% packet loss, time 2001msrtt min/avg/max/mdev = 0.416/0.700/1.263/0.398 ms[teluser@TeleComm07 ~]$

No. Time Source Destination Protocol Info 4 20.687905 Dell_20:6e:bd Broadcast ARP Who has 10.0.2.139? Tell 10.0.2.137 5 20.688201 Dell_20:67:71 Dell_20:6e:bd ARP 10.0.2.139 is at 00:1a:a0:20:67:71 6 20.688235 10.0.2.137 10.0.2.139 ICMP Echo (ping) request 7 20.688566 10.0.2.139 10.0.2.137 ICMP Echo (ping) reply 8 21.688814 10.0.2.137 10.0.2.139 ICMP Echo (ping) request 9 21.689194 10.0.2.139 10.0.2.137 ICMP Echo (ping) reply 10 22.688729 10.0.2.137 10.0.2.139 ICMP Echo (ping) request 11 22.689107 10.0.2.139 10.0.2.137 ICMP Echo (ping) reply 12 25.688326 Dell_20:67:71 Dell_20:6e:bd ARP Who has 10.0.2.137? Tell 10.0.2.139 13 25.688352 Dell_20:6e:bd Dell_20:67:71 ARP 10.0.2.137 is at 00:1a:a0:20:6e:bd


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Figures 28, 29, 30, and 31 show the ARP table, routing table, and routing cache of each host before issuing the ping commands. Note that they are the same as the previous table entries in Tables 10, 11, 12, and 13.




[teluser@telecomm05 ~]$ sudo arp -a[teluser@telecomm05 ~]$ sudo routeKernel IP routing tableDestination Gateway Genmask Flags Metric Ref Use Iface10.0.1.0 * 255.255.255.0 U 0 0 0 eth010.0.2.0 10.0.1.1 255.255.255.0 UG 0 0 0 eth0192.168.122.0 * 255.255.255.0 U 0 0 0 virbr0[teluser@telecomm05 ~]$ sudo route -CKernel IP routing cacheSource Destination Gateway Flags Metric Ref Use Iface* 224.0.0.1 224.0.0.1 ml 0 0 1 lo[teluser@telecomm05 ~]$

[teluser@TeleComm06 ~]$ sudo arp -a[teluser@TeleComm06 ~]$ sudo routeKernel IP routing tableDestination Gateway Genmask Flags Metric Ref Use Iface10.0.1.0 10.0.2.138 255.255.255.0 UG 0 0 0 eth010.0.2.0 * 255.255.255.0 U 0 0 0 eth0[teluser@TeleComm06 ~]$ sudo route -CKernel IP routing cacheSource Destination Gateway Flags Metric Ref Use Iface[teluser@TeleComm06 ~]$

[teluser@TeleComm07 ~]$ sudo arp -a? (10.0.2.139) at <incomplete> on eth0[teluser@TeleComm07 ~]$ sudo routeKernel IP routing tableDestination Gateway Genmask Flags Metric Ref Use Iface10.0.2.136 * 255.255.255.248 U 0 0 0 eth010.0.1.0 10.0.2.138 255.255.255.0 UG 0 0 0 eth010.0.2.0 10.0.2.138 255.255.255.0 UG 0 0 0 eth0[teluser@TeleComm07 ~]$ sudo route -CKernel IP routing cacheSource Destination Gateway Flags Metric Ref Use Iface10.0.2.137 10.0.2.139 10.0.2.139 0 0 0 eth0[teluser@TeleComm07 ~]$


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Figures 32 shows the ARP table, routing table, and routing cache of PC3 AFTER issuing the ping.




Figure 34 shows the Wireshark output on PC3

[teluser@TeleComm08 ~]$ sudo arp -a? (10.0.2.137) at <incomplete> on eth0[teluser@TeleComm08 ~]$ sudo routeKernel IP routing tableDestination Gateway Genmask Flags Metric Ref Use Iface10.0.1.0 10.0.2.138 255.255.255.0 UG 0 0 0 eth010.0.2.0 * 255.255.255.0 U 0 0 0 eth0[teluser@TeleComm08 ~]$ sudo route -CKernel IP routing cacheSource Destination Gateway Flags Metric Ref Use Iface[teluser@TeleComm08 ~]$

[teluser@TeleComm07 ~]$ sudo arp -a? (10.0.2.10) at 00:1a:a0:22:0d:4b [ether] on eth0? (10.0.2.138) at 1c:df:0f:9a:b1:c1 [ether] on eth0[teluser@TeleComm07 ~]$ sudo routeKernel IP routing tableDestination Gateway Genmask Flags Metric Ref Use Iface10.0.2.136 * 255.255.255.248 U 0 0 0 eth010.0.1.0 10.0.2.138 255.255.255.0 UG 0 0 0 eth010.0.2.0 10.0.2.138 255.255.255.0 UG 0 0 0 eth0[teluser@TeleComm07 ~]$ sudo route -CKernel IP routing cacheSource Destination Gateway Flags Metric Ref Use Iface10.0.2.138 10.0.2.137 10.0.2.137 il 0 0 1 lo10.0.2.137 10.0.2.10 10.0.2.10 0 0 1 eth010.0.2.10 10.0.2.137 10.0.2.137 l 0 0 3 lo10.0.2.137 10.0.2.10 10.0.2.10 0 0 2 eth0[teluser@TeleComm07 ~]$

[teluser@TeleComm07 ~]$ sudo ping -c 3 10.0.2.10PING 10.0.2.10 (10.0.2.10) 56(84) bytes of data.From 10.0.2.138: icmp_seq=1 Redirect Host(New nexthop: 10.0.2.10)64 bytes from 10.0.2.10: icmp_seq=1 ttl=64 time=3.19 msFrom 10.0.2.138: icmp_seq=2 Redirect Host(New nexthop: 10.0.2.10)64 bytes from 10.0.2.10: icmp_seq=2 ttl=64 time=0.745 ms64 bytes from 10.0.2.10: icmp_seq=3 ttl=64 time=0.369 ms

--- 10.0.2.10 ping statistics ---3 packets transmitted, 3 received, 0% packet loss, time 2001msrtt min/avg/max/mdev = 0.369/1.435/3.191/1.251 ms


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PC3 will not broadcast to PC2 because PC2’s IP address is not part of PC3’s ‘/29’ subnet. When PC3 tries to ping to PC2, it has to use the router even though it is connected to the same Ethernet hub. If we did not set the routing tables to route PC3 messages to network 10.0.2.0, there would be no communication between PC2 and PC3 even though they are plugged into the same hub.

7 ConclusionThis experiment was very comprehensive and took a lot of time to setup the network, but it was essential to understand how ICM is applied and network traffic is routed across the network.

No. Time Source Destination Protocol Info 122 1013.553418 Dell_20:6e:bd Broadcast ARP Who has 10.0.2.138? Tell 10.0.2.137 123 1013.553985 Cisco_9a:b1:c1 Dell_20:6e:bd ARP 10.0.2.138 is at 1c:df:0f:9a:b1:c1 124 1013.554035 10.0.2.137 10.0.2.10 ICMP Echo (ping) request 125 1013.554526 10.0.2.138 10.0.2.137 ICMP Redirect (Redirect for host) 126 1013.554627 10.0.2.137 10.0.2.10 ICMP Echo (ping) request 127 1013.555762 Dell_22:0d:4b Broadcast ARP Who has 10.0.2.137? Tell 10.0.2.10 128 1013.555790 Dell_20:6e:bd Dell_22:0d:4b ARP 10.0.2.137 is at 00:1a:a0:20:6e:bd 129 1013.556040 10.0.2.10 10.0.2.137 ICMP Echo (ping) reply 130 1014.554212 10.0.2.137 10.0.2.10 ICMP Echo (ping) request


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Appendix – I

router1#show interfaceGigabitEthernet0/0 is up, line protocol is up Hardware is CN Gigabit Ethernet, address is 1cdf.0f9a.b1c0 (bia 1cdf.0f9a.b1c0) Description: $ETH-LAN$$ETH-SW-LAUNCH$$INTF-INFO-GE 0/0$ Internet address is 10.0.2.1/24 MTU 1500 bytes, BW 10000 Kbit/sec, DLY 1000 usec, reliability 255/255, txload 1/255, rxload 1/255 Encapsulation ARPA, loopback not set Keepalive set (10 sec) Half-duplex, 10Mb/s, media type is RJ45 output flow-control is unsupported, input flow-control is unsupported ARP type: ARPA, ARP Timeout 04:00:00 Last input 00:02:33, output 00:02:33, output hang never Last clearing of "show interface" counters never Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0 Queueing strategy: fifo Output queue: 0/40 (size/max) 5 minute input rate 0 bits/sec, 0 packets/sec 5 minute output rate 0 bits/sec, 0 packets/sec 2 packets input, 120 bytes, 0 no buffer Received 0 broadcasts, 0 runts, 0 giants, 0 throttles 0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored 0 watchdog, 0 multicast, 0 pause input 0 input packets with dribble condition detected 883 packets output, 94376 bytes, 0 underruns 0 output errors, 0 collisions, 0 interface resets 0 unknown protocol drops 0 babbles, 0 late collision, 0 deferred 0 lost carrier, 0 no carrier, 0 pause output 0 output buffer failures, 0 output buffers swapped outGigabitEthernet0/1 is up, line protocol is up Hardware is CN Gigabit Ethernet, address is 1cdf.0f9a.b1c1 (bia 1cdf.0f9a.b1c1) Internet address is 10.0.3.1/24 MTU 1500 bytes, BW 10000 Kbit/sec, DLY 1000 usec, reliability 255/255, txload 1/255, rxload 1/255 Encapsulation ARPA, loopback not set Keepalive set (10 sec) Half-duplex, 10Mb/s, media type is RJ45 output flow-control is unsupported, input flow-control is unsupported ARP type: ARPA, ARP Timeout 04:00:00 Last input never, output 00:03:11, output hang never Last clearing of "show interface" counters never Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0 Queueing strategy: fifo Output queue: 0/40 (size/max) 5 minute input rate 0 bits/sec, 0 packets/sec 5 minute output rate 0 bits/sec, 0 packets/sec 0 packets input, 0 bytes, 0 no buffer Received 0 broadcasts, 0 runts, 0 giants, 0 throttles 0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored


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0 watchdog, 0 multicast, 0 pause input 0 input packets with dribble condition detected 882 packets output, 94316 bytes, 0 underruns 0 output errors, 0 collisions, 0 interface resets 0 unknown protocol drops 0 babbles, 0 late collision, 0 deferred 0 lost carrier, 0 no carrier, 0 pause output 0 output buffer failures, 0 output buffers swapped outSerial0/0/0 is administratively down, line protocol is down Hardware is WIC MBRD Serial MTU 1500 bytes, BW 1544 Kbit/sec, DLY 20000 usec, reliability 255/255, txload 1/255, rxload 1/255 Encapsulation HDLC, loopback not set Keepalive set (10 sec) Last input never, output never, output hang never Last clearing of "show interface" counters never Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0 Queueing strategy: weighted fair Output queue: 0/1000/64/0 (size/max total/threshold/drops) Conversations 0/0/256 (active/max active/max total) Reserved Conversations 0/0 (allocated/max allocated) Available Bandwidth 1158 kilobits/sec 5 minute input rate 0 bits/sec, 0 packets/sec 5 minute output rate 0 bits/sec, 0 packets/sec 0 packets input, 0 bytes, 0 no buffer Received 0 broadcasts, 0 runts, 0 giants, 0 throttles 0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort 0 packets output, 0 bytes, 0 underruns 0 output errors, 0 collisions, 3 interface resets 0 unknown protocol drops 0 output buffer failures, 0 output buffers swapped out 0 carrier transitions DCD=down DSR=down DTR=down RTS=down CTS=down

router1#show running-configBuilding configuration...

Current configuration : 4952 bytes!! Last configuration change at 21:44:05 UTC Fri Oct 24 2014 by root!version 15.0service timestamps debug datetime msecservice timestamps log datetime msecno service password-encryption!hostname router1!boot-start-markerboot-end-marker!logging buffered 51200 warningsenable secret 5 $1$aShH$C1HonGi6obRnwY5Kiuwsh.!no aaa new-model!no ipv6 cef


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ip source-routeip cef! !!!no ip domain lookupip domain name yourdomain.commultilink bundle-name authenticated!!crypto pki trustpoint TP-self-signed-1602601375 enrollment selfsigned subject-name cn=IOS-Self-Signed-Certificate-1602601375 revocation-check none rsakeypair TP-self-signed-1602601375!!crypto pki certificate chain TP-self-signed-1602601375 certificate self-signed 01 3082024E 308201B7 A0030201 02020101 300D0609 2A864886 F70D0101 04050030 31312F30 2D060355 04031326 494F532D 53656C66 2D536967 6E65642D 43657274 69666963 6174652D 31363032 36303133 3735301E 170D3130 31313035 32323439 33375A17 0D323030 31303130 30303030 305A3031 312F302D 06035504 03132649 4F532D53 656C662D 5369676E 65642D43 65727469 66696361 74652D31 36303236 30313337 3530819F 300D0609 2A864886 F70D0101 01050003 818D0030 81890281 8100D579 B8C9DCA0 78A1E8E1 FDC80511 D8DDE306 0452B99D 6B0D0715 CDC07EC8 20E7BE63 3189F879 740D770A 30EEA615 7156CBFB 1772C681 A6079737 9E0BAEE2 61ECD649 95543A3E E0D2C938 B38041DF 96CA633B F9BA321C 7CB2CF10 08C6FB6D 6ED76348 F8CDA57E 04E334EB CD6D9697 BA005664 69F1489F 6486B9E8 224B5DC6 2EAB0203 010001A3 76307430 0F060355 1D130101 FF040530 030101FF 30210603 551D1104 1A301882 16726F75 74657231 2E796F75 72646F6D 61696E2E 636F6D30 1F060355 1D230418 30168014 589E8147 CD7C0951 B9F383FE 9849E21D 9B7E00DC 301D0603 551D0E04 16041458 9E8147CD 7C0951B9 F383FE98 49E21D9B 7E00DC30 0D06092A 864886F7 0D010104 05000381 81005256 E0669602 9AABDC37 A6E09AFC 608BB5A6 6DB8549E 46349C77 EDBE2828 26324122 7FA84994 F188A786 166082AB 41798069 B51B33AC 0D3BB9BF 77173721 4F7FC725 9BADE0B3 A6727CFF 56C85E63 33A19289 81815E2C BB957DE2 C3AFDB12 4E238CAD E5CDE7F2 360EB51E DA7D7BF4 B65C16B8 453FD93B 6FF83B96 A3134FFD 2C40 quitlicense udi pid CISCO1941/K9 sn FTX143682J2!!username cisco privilege 15 one-time secret 5 $1$37qV$pyimX5BJ0L8MNM8ZYm4Ju0username root privilege 15 password 0 level3!!!! !!interface GigabitEthernet0/0 description $ETH-LAN$$ETH-SW-LAUNCH$$INTF-INFO-GE 0/0$ ip address 10.0.2.1 255.255.255.0 duplex auto speed auto!


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interface GigabitEthernet0/1 ip address 10.0.3.1 255.255.255.0 duplex auto speed auto!interface Serial0/0/0 no ip address shutdown clock rate 2000000!ip forward-protocol nd!ip http serverip http access-class 23ip http authentication localip http secure-serverip http timeout-policy idle 60 life 86400 requests 10000!!access-list 23 permit 10.10.10.0 0.0.0.7!!!control-plane!banner exec ^C% Password expiration warning.----------------------------------------------------------------------- Cisco Configuration Professional (Cisco CP) is installed on this device and it provides the default username "cisco" for one-time use. If you have already used the username "cisco" to login to the router and your IOS image supports the "one-time" user option, then this username has already expired. You will not be able to login to the router with this username after you exit this session. It is strongly suggested that you create a new username with a privilege level of 15 using the following command. username <myuser> privilege 15 secret 0 <mypassword> Replace <myuser> and <mypassword> with the username and password you want to use. -----------------------------------------------------------------------^Cbanner login ^C-----------------------------------------------------------------------Cisco Configuration Professional (Cisco CP) is installed on this device. This feature requires the one-time use of the username "cisco" with the password "cisco". These default credentials have a privilege level of 15. YOU MUST USE CISCO CP or the CISCO IOS CLI TO CHANGE THESE PUBLICLY-KNOWN CREDENTIALS

Here are the Cisco IOS commands.


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username <myuser> privilege 15 secret 0 <mypassword>no username cisco

Replace <myuser> and <mypassword> with the username and password you want to use.

IF YOU DO NOT CHANGE THE PUBLICLY-KNOWN CREDENTIALS, YOU WILL NOT BE ABLE TO LOG INTO THE DEVICE AGAIN AFTER YOU HAVE LOGGED OFF. For more information about Cisco CP please follow the instructions in the QUICK START GUIDE for your router or go to http://www.cisco.com/go/ciscocp -----------------------------------------------------------------------^C!line con 0 login localline aux 0line vty 0 4 access-class 23 in privilege level 15 login local transport input telnet sshline vty 5 15 access-class 23 in privilege level 15 login local transport input telnet ssh!scheduler allocate 20000 1000end

Brian_Lee_Static_Routing

Documents

routing configuration

router configuration

static routing tablesfor

static routing table

lab objectives

cisco router

finalizing network setup

report p