Linux Network commands

My ConnectionMy Connection

Network Configuration..Network Configuration..

$ smbtree$ smbtree

Think about it for a second !!!! Think about it for a second !!!!

Why single physical interface Why single physical interface should be limited to single IP should be limited to single IP

address?? address??

ifconfig eth0 <ip> netmask 10.248.255.0 upifconfig eth0 <ip> netmask 10.248.255.0 up

sudo route add default gw 10.1.1.2sudo route add default gw 10.1.1.2

Test Connection..Test Connection..

user@computer-name:~$ ping www.google.comuser@computer-name:~$ ping www.google.comPING www.l.google.com (66.102.13.106) 56(84) bytes of dataPING www.l.google.com (66.102.13.106) 56(84) bytes of data..

DNS Tools..DNS Tools..

host:used to map names to IP add.host:used to map names to IP add.

$ host www.google.com$ host www.google.com www.google.com is an alias for www.l.google.com.www.google.com is an alias for www.l.google.com. www.l.google.com has address 66.102.13.104www.l.google.com has address 66.102.13.104

nslookup

nslookup 66.102.13.103nslookup 66.102.13.103

$ whois 66.102.13.103

$ traceroute www.amazoon.com$ traceroute www.amazoon.com

How many hops until some destination?How many hops until some destination?

Netstat : List listening sockets ,

associated port# and process.

netstat -l -p -nnetstat --tcpnetstat --udpnetstat -inetstat -s

ethtool:ethtool:What driver is responsible for What driver is responsible for

certain network interfacecertain network interface

$ ethtool -i <interface>$ ethtool -i <interface>

$ ethtool <interface>$ ethtool <interface>

finger: to contact the necessary server and retrieve info. about user.

finger Email || usernamefinger Email || username

Arp - Route

$ route -v$ route -v

$ arp $ arp

Show routing information

List ARP table (MAC-IP)

Security Tools

FireWall..FireWall..

sudo ufw enablesudo ufw enable disabledisable

Nmap:

sudo nmap 192.168.1.1-255 sudo nmap 192.168.1.1-255

nmap localhostnmap localhost

Netcat : The network Swiss army knife

$ nc -v -w1 localhost -z From-ToPort $ nc -v -w1 localhost -z From-ToPort

tcpdump : a packet sniffertcpdump : a packet sniffer

$ tcpdump -i eth0$ tcpdump -i eth0

$ tcpdump -w file -i eth0$ tcpdump -w file -i eth0

$ tcpdump -tttt -r file$ tcpdump -tttt -r file

$ tcpdump -n -i eth0$ tcpdump -n -i eth0

$ tcpdump -i eth0 arp$ tcpdump -i eth0 arp

$ tcpdump -i eth0 port 22$ tcpdump -i eth0 port 22

Capture packets > file

from particular port

packets of protocol type

Capture packets with IPs

Read sniffing data

Browsers from Terminal!!

lynx www.google.com

lynx www.facebook.com

wget www.google.com

Talk (MultiUser)

talktalk

wallwall

writewrite

Telnet vs SSHTelnet vs SSH

$ ufw allow 23

$ telnet localhost

sudo apt-get install telnetd

Just try to ping it.. then telnet it

Telnet Telnet

SSHSecure Shell, a network protocol for remote

administration of Unix computers

$ sudo apt-get install openssh-server

$ ufw allow 22

$ nmap localhost

$ ssh user@pc-name

PuTTY

An open source telnet and SSH Client for Windows ..

Send messages between 2 Ubuntu PCs

ssh <user name>@<ip address>

export DISPLAY=:0.0notify-send "Title” "message text"

References:

1.http://www.alexonlinux.com/useful-linux-networking-commands2.http://www.alexonlinux.com/tcpdump-for-dummies

3.http://www.karakas-online.de/gnu-linux-tools-summary/network-commands.html

4.http://www.linuxplanet.com/linuxplanet/tutorials/7044/1/5.http://aalagha.com/blog/2008/01/22/netcat-swiss-army-knife

6.http://www.dd-wrt.com/wiki/index.php/SSH7.http://www.slideshare.net/tmavroidis/linuxnetworkingcommands

8. http://sectools.org/9.http://askubuntu.com/questions/31582/send-messages-between

-2-ubuntu-pcs-net-send-style10.http://ubuntuforums.org/showthread.php?t=100198

11.http://linux.about.com/od/commands/l/blcmdl1_talk.htm12.http://forum.codecall.net/linux-networking/index3.html