Postfix Configuration

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Admin Guide ( Unix System Administration)

Postfix Configuration

Postfix - Mail Transfer Agent. The goal of the Postfix project is to implement an alternative

to the UNIX Sendmail program. Postfix is fast, easy to administer, and secure.To configure Postfix , log in as admin, select the System Administration mode and findPostfix Configuration in the E-Mail Management section. Alternatively, click PostfixConfiguration in the System monitor section on the left panel.

• Module Config: checks and configures CP+ Postfix settings (paths to Postfixbinaries and config files, etc.)

• General Options provides access to most of main.cf and master.cf options.

• Address Rewriting and Masquerading configures options of addressmasquerading and rewriting addresses to standard form.

• Mail Aliases configures mail aliases for local email addresses.• Canonical Mapping configures canonical mapping options and to edit canonical

maps.• Virtual Domains configures virtual domain options and to create/edit virtual maps.• Transport Mapping specifies transport mapping lookup tables.•

Relocated Mapping specifies relocated mapping lookup tables.• Header Checks allows email to be redirected based on its headers.• Body Checks allows email to be redirected based on the contents of the message

body.• Local delivery configures local delivery options.• General resource control controls general resources.• SMTP server options configures SMTP server options.• SMTP client options configures SMTP client options.• Delivery rates gives direct control over inbound and outbound delivery rates.• Debugging features debugs parts of the Postfix mail system when things do not

work according to expectation.• Server Processes manage the various server processes used by Postfix for

receiving and processing email.• LDAP lookups specifies lookup tables as LDAP databases.

http://192.168.70.160/docs/cpplus_admin.html

http://192.168.70.160/docs/postfix_configuration.html#module_config


http://192.168.70.160/docs/postfix_configuration.html#options


http://192.168.70.160/docs/postfix_configuration.html#adress_rewriting

http://192.168.70.160/docs/postfix_configuration.html#mail_aliases


http://192.168.70.160/docs/postfix_configuration.html#canonical_mapping


http://192.168.70.160/docs/postfix_configuration.html#virtual_domains

http://192.168.70.160/docs/postfix_configuration.html#transport_mapping


http://192.168.70.160/docs/postfix_configuration.html#relocated_mapping


http://192.168.70.160/docs/postfix_configuration.html#header_checks


http://192.168.70.160/docs/postfix_configuration.html#body_checks


http://192.168.70.160/docs/postfix_configuration.html#local_delivery


http://192.168.70.160/docs/postfix_configuration.html#general_resource_control

http://192.168.70.160/docs/postfix_configuration.html#smtp_server_options


http://192.168.70.160/docs/postfix_configuration.html#smtp_client_options


http://192.168.70.160/docs/postfix_configuration.html#delivery_rates


http://192.168.70.160/docs/postfix_configuration.html#debugging_features

http://192.168.70.160/docs/postfix_configuration.html#server_processes


http://192.168.70.160/docs/postfix_configuration.html#ldap_lookups




http://192.168.70.160/docs/postfix_configuration.html#adress_rewriting



http://192.168.70.160/docs/postfix_configuration.html#virtual_domains






http://192.168.70.160/docs/postfix_configuration.html#general_resource_control




http://192.168.70.160/docs/postfix_configuration.html#debugging_features



http://192.168.70.160/docs/cpplus_admin.html



• Mail Queue the list of queued messages.• Configuration Check checks main Postfix options.• User Mailboxes the list of mailboxes with access to mail in them.

CP+ Postfix Module Configuration

Configure CP+ Postfix module by clicking on the Module Config link in the top right corner of the page. There are two sections dealing with CP+ Postfix configuration:

1) Configurable options:

2) System configuration with paths to Postfix binaries, configs, logs, etc.

• Full path to Postfix control command: postfix - Postfix control program. The

postfix command controls the operation of the Postfix mail system: starts or stopsthe master daemon, does a health check, and other maintenance. The postfixcommand sets up a standardized environment and runs the postfix-script shellscript to do the actual work.

• Full path to Postfix config command: postconf - Postfix configuration utility.

The postconf command prints the actual value of parameter (all known parametersby default) one parameter per line, changes its value, or prints other informationabout the Postfix mail system.

• Full path to Postfix config file: Postfix has several hundred configurationparameters that are controlled via the main.cf file, but all parameters have

sensible default values.• Full path to Postfix aliases generation command: the postalias command

creates or queries one or more Postfix alias databases, or updates an existing one.• Full path to "newaliases" (Sendmail compatibility) command: initialize the alias

http://192.168.70.160/docs/postfix_configuration.html#mail_queue


http://192.168.70.160/docs/postfix_configuration.html#configuration_check

http://192.168.70.160/docs/postfix_configuration.html#user_mailboxes



http://192.168.70.160/docs/postfix_configuration.html#configuration_check




database.• Full path to Postfix lookup table command management (`postmap'): the

postmap command creates or queries one or more Postfix lookup tables, or updatesan existing one.

• Full path to Postfix queue management command (`postqueue'): the postqueuecommand implements the Postfix user interface for queue management.

• Mail queue base directory: the directory with Postfix queue files, with local inter-process communication endpoints, and with files needed for daemon programs thatrun in the optional chrooted environment.

• Mail queue display command: list the mail queue.• Mail queue decoding command: postcat - shows Postfix queue file contents.

The postcat command prints the contents of the named files in human- readableform. The files are expected to be in Postfix queue file format. If no files arespecified on the command line, the program reads from standard input.

By default, Postfix configuration files are in /etc/postfix. The two most important files

are main.cf and master.cf; these files must be owned by root. Giving someone else

write permission to main.cf or master.cf (or to their parent directories) means givingroot privileges to that person.Make sure to click Save to preserve changes.

General Options

The General Options form consists of two sections:

1) Most Useful General Options:

• What domain to use in outbound mail: specifies the domain that appears in mailthat is posted on this machine. The default configuration of Postfix is to use the localmachine name, hostname.

• What domains to receive mail for: specifies what domains this machine willdeliver for locally, instead of forwarding mail to another machine.

• What trouble to report to the postmaster: sets up a postmaster alias. This alias isrequired to exist, so that people can report mail delivery problems. The Postfixsystem itself also reports problems to the postmaster alias. You may not be

interested in all types of trouble reports, so this reporting mechanism isconfigurable. The default is to report only serious problems (resource, software) topostmaster.

2) Other General Options:



• Send outgoing mail via host: by default, Postfix forward any outgoing mail notdestined for users of system to the given host. To forward all mail to an intranet mailgateway (for example if intranet has a firewall), except for mail for the localmachine, setup the value to mail gateway. (ex.: $mydomain or

[mail.$mydomain] - deliver via local mailhub; [mail.isp.tld] - deliver via

provider mailhub).• Address that receives bcc of each message: specifies an optional address that

receives a copy of each message that enters the Postfix system, not includingbounces that are generated locally.

• Timeout on handling requests: specifies how much time a daemon may take to

handle a request before it assumes it is wedged and commits suicide.• Default database type: specifies the default database type to use in postalias

and postmap commands. On many UNIX systems the default type is either `dbm'

or `hash'. The default is determined when the Postfix system is built.

• Default message delivery transport: specifies the default message deliverytransport to use when no transport is explicitly given in the optional transport table.Common values are uucp or smtp.

• Sender address for bounce mail: specifies the sender address for mail that mustbe discarded when it cannot be delivered. This must be a unique name. All mail tothis name is silently discarded, in order to terminate mail bounce loops.

•

Number of subdir levels below the queue dir: specifies the number of subdirectory levels below the queue directories listed in the hash_queue_names

parameter. Multiple subdirectory levels can speed up directory access by reducing



the number of files per directory.• Name of queue dirs split accross subdirs: specifies the names of queue

directories that are split across multiple subdirectory levels. Hashing MUST NOT beused with a world-writable maildrop directory. Hashing MUST be used for the defer logfile directory, or mail system performance will suffer.

• Max number of Received: headers: limits the number of Received: message

headers. A message that exceeds the limit is bounced.• Time in hours before sending a warning for no delivery: specifies after how

many hours a warning is sent that mail has not yet been delivered. By default, nowarning is sent.

• Network interfaces for receiving mail: specifies the network interface addressesthat this mail system receives mail on. By default, the software claims all activeinterfaces on the machine. The parameter also controls delivery of mail touser@[ip.address] ( ex.: $myhostname).

• Idle time after internal IPC client disconnects: bounds the idle time in secondsafter which an internal IPC client disconnects. The purpose is to allow servers toterminate voluntarily. Currently this is used by the address resolving and rewriting

clients.• Mail system name: specifies the mail system name that is used in Received:

headers, in the SMTP greeting banner, and in bounced mail.• Official mail system version: specifies the official version of the mail system. The

version string can be used in, for example, the SMTP greeting banner.• Time to wait for next service request: limits the time in seconds that a Postfix

daemon process waits for the next service request before exiting. This parameter isignored by the Postfix queue manager.

• Internet hostname of this mail system: specifies the internet hostname of thismail system. The default is to use the fully-qualified domain name from

gethostname.• Local internet domain name: specifies the local internet domain name. The

default is to use $myhostname minus the first component.

• Local networks: specifies the list of networks that are local to this machine. The listis used by the anti-UCE software to distinguish local clients from strangers.

• Send postmaster notice on bounce to...: specifies who gets postmaster notices if the above error conditions is recognized. Defaults to "postmaster".

• Send postmaster notice on 2bounce to...: specifies who gets postmaster noticesif the above error conditions is recognized. Defaults to "postmaster".

• Send postmaster notice on delay to...: specifies who gets postmaster notices if the above error conditions is recognized. Defaults to "postmaster".

• Send postmaster notice on error to...: specifies who gets postmaster notices if the above error conditions is recognized. Defaults to "postmaster".

• Mail queue directory: specifies the location of the Postfix queue. This is also theroot directory of Postfix daemons that run chrooted.

• Lock file dir, relative to queue dir: specifies a lock file directory relative to thePostfix queue directory. This facility is used by the master daemon to lock out other master daemon instances.

• Separator between user names and address extensions: specifies the separator between user names and address extensions (user+foo).

• Postfix support programs and daemons dir: specifies the location of Postfix

support programs and daemons. This directory must be owned by root.• Relocated mapping lookup tables: specifies optional tables with contact

information for users, hosts or domains that no longer exist. See Relocated



Mapping for details. By default, this feature is disabled ( ex.:

hash:/etc/postfix/relocated).

• Disable kernel file lock on mailboxes: disables kernel file locks on mailboxes.This is needed on SUN workstations because the mailtool program keeps an

exclusive kernel lock while its window is open. SUN software uses user.lock files

only. Unless you remove all SUN mail software, kernel locks just give a false sense

of security.• Max time to send a trigger to a daemon: limits the time to send a trigger to a

Postfix daemon. This prevents programs from getting stuck when the mail system isunder heavy load.

• Email content filter: specifies the name of a mail delivery transport that filters mailafter it is queued. By default, this feature is disabled. Sensible possible value:spamfilter, assuming that a transport called spamfilter has been defined.

Make sure to click Save and Apply to preserve changes.

Address Rewriting and Masquerading

Before the cleanup daemon runs an address through any lookup table, it first rewrites theaddress to the standard [email protected] form, by sending the address to thetrivial-rewrite daemon. The purpose of rewriting to standard form is to reduce the number of entries needed in lookup tables.

• Rewrite "user%domain" to "user@domain": is controlled by the boolean

allow_percent_hack parameter (default: yes). Typically, this is used in order to

deal with monstrosities such as user%domain@otherdomain.

• Rewrite "user@host" to "user@host.$mydomain": is controlled by the

boolean append_dot_mydomain parameter (default: yes). The purpose is to get

consistent treatment of different forms of the same hostname.• Rewrite "user" to "user@$mydomain": is controlled by the boolean

append_at_myorigin parameter (default: yes). The purpose is to get consistenttreatment of user on every machine in $myorigin.

• Rewrite "site!user" to "user@site": is controlled by the boolean

swap_bangpath parameter (default: yes). The purpose is to rewrite UUCP-style

addresses to domain style. This is useful only when you receive mail via UUCP, butit probably does not hurt otherwise.

• Send mail with empty recipient to...: specifies the destination for mail from <>that is undeliverable (typically, bounce notifications and other notifications). Bydefault, such mail is sent to MAILER-DAEMON.

• Address masquerading: it is a method to hide all hosts below a domain behind

their mail gateway, and to make it appear as if the mail comes from the gatewayitself, instead of from individual machines.

• Masquerade exceptions: specifies what user names should not be subjected to



address masquerading.


Mail Aliases

Aliases - format of the Postfix alias database. The aliases file provides a system-widemechanism to redirect mail for local recipients.

1) Alias Options

• Alias databases used by the local delivery agent: specifies the list of aliasdatabases used by the local delivery agent.

• Alias databases built by Postfix: specifies the alias database(s) that are built with"newaliases" or "sendmail -bi".


2) Alias Properties Edition

3) Edit Alias Properties

To edit the existent aliases, click on the user's name in the list, and you will see the formsimilar to the form to create aliases. Each time you edit a user account, you may add anew Alias To field:

• Address: an address to be aliased must not include its domain name, it must beksmith instead of [email protected].

•

Enabled: an alias may be enabled or disabled. Disabled aliases are ignored whenprocessing incoming email.• Alias To: each alias may redirect mail to several recipients, and each recipient may

be one of the following:



• Email Address - a full email address (with domain name) or local address(without domain name).

• Addresses in File - pathname to the file with the list of addresses one per line.• Write to File - email will be written to the specified file. To have all email to some

address thrown away, give /dev/null as the filename.• Feed to Program- pathname to a program that starts each time an email message

comes from this address and takes the message as its standard input.• Autoreply From File - simply sends a mail automatically back to the sender

containing whatever is in the file listed in the text field.

Canonical Mapping

The canonical mapping is used by the cleanup daemon, before the cleanup daemonstores inbound mail into the incoming queue, it uses the canonical table to rewrite alladdresses in message envelopes and in message headers, local or remote. The canonicalmapping is useful to replace login names by Firstname.Lastname style addresses, or toclean up invalid domains in mail addresses produced by legacy mail systems.

• Address mapping lookup tables: specifies optional address mapping lookuptables. The mapping is applied to both sender and recipient addresses, in bothenvelopes and in headers. This is typically used to clean up dirty addresses fromlegacy mail systems, or to replace login names by Firstname.Lastname (ex.:

hash:/etc/postfix/canonical ).• Tables for RECIPIENT addresses: specifies optional address mapping lookup

tables for envelope and header RECIPIENT addresses (ex.:

hash:/etc/postfix/recipient_canonical ).

• Tables for SENDER addresses: specifies optional address mapping lookup tablesfor envelope and header SENDER addresses (ex.:

hash:/etc/postfix/sender_canonical ).

Click on one of these buttons to edit the canonical maps:


Virtual Domains

After applying the canonical and masquerade mappings, the cleanup daemon uses thevirtual table to redirect mail for all recipients, local or remote. The mapping affects onlyenvelope recipients; it has no effect on message headers or envelope senders. Virtuallookups are useful to redirect mail for virtual domains to real user mailboxes, and toredirect mail for domains that no longer exist.



• Domain mapping lookup tables: specifies one or more lookup tables.

You may create new maps or edit the existent ones. To edit, click on the user's name inthe list, and you will see the form similar to the form to create maps.

The form to create maps:

The form to edit maps:

Make sure to click Save and Apply or Save mapping to preserve changes.

Transport Mapping

Once the queue manager has established the destination of a message, the optionaltransport table controls how the message will be delivered (this table is used by theaddress rewriting and resolving daemon). By default, everything is sent via the smtptransport.

• Transport mapping lookup tables: specifies optional tables with domain to(transport, nexthop) mappings (ex.: hash:/etc/postfix/transport).


Relocated Mapping

Relocated maps - list of lookup tables for relocated users or sites. The queue manager runs each recipient name through the relocated database. This table provides informationon how to reach users that no longer have an account, or what to do with mail for entiredomains that no longer exist. When mail is sent to an address that is listed in this table, the

message is bounced with an informative message.

• Relocated mapping lookup tables: specifies optional tables with contactinformation for users, hosts or domains that no longer exist ( ex.:

hash:/etc/postfix/relocated).


Header Checks

The optional header checks table allows email to be redirected based on its headers. Each



entry in the table has a POSIX regular expression on the left-hand side, and an action onthe right.


Body Checks

The optional body checks table allows email to be redirected based on the contents of themessage body. Each entry in the table has a POSIX regular expression on the left-handside, and an action on the right.


Local delivery

The local daemon processes delivery requests from the Postfix queue manager to deliver mail to local recipients. Each delivery request specifies a queue file, a sender address, adomain or host to deliver to, and one or more recipients.

• Name of the transport for local deliveries: specifies the name of the transport for delivery to destinations that match $mydestination or $inet_interfaces.

• Shell to use for delivery to external command: controls what shell will be usedfor delivery to external command.

• Search list for forward: specifies a search list. The first file that is found is used.• Valid mail delivery to external commands: restricts mail delivery to external

commands.

• Valid mail delivery to external files: restricts mail delivery to external file.• Default rights of the delivery agent: specifies the default rights used by the local

delivery agent for delivery to external file or command.



• Home-relative pathname of user mailbox file: specifies the optional pathname of a mailbox file relative to a user's home directory.

• Destination address for unknown recipients: specifies an optional destinationaddress for unknown recipients.

• Spool directory: specifies the directory where UNIX-style mailboxes are kept.• External command to use instead of mailbox delivery: specifies the optional

external command to use instead of mailbox delivery.• Optional actual transport to use: specifies the optional transport (in master.cf)

to use after processing aliases and .forward files.

• Optional transport for unknown recipients: specifies the optional transport inmaster.cf to use for recipients that are not found in the UNIX passwd database.

• Max number of parallel deliveries to the same local recipient: limits the number of parallel deliveries to the same local recipient.

• Max number of recipients per local message delivery: limits the number of recipients per local message delivery.

• Prepend a Delivered-To: when...: controls when Postfix should prepend aDelivered-To: message header.


General resource control

• Max size of bounced message: limits the amount of original message context inbytes that is sent in a non-delivery notification.

• Max time for delivery to external commands: limits the amount of time for delivery to external commands. This limit is used by the local delivery agent, and isthe default time limit for delivery by the pipe mailer.

• Max number of Postfix child processes: specifies the default limit on the number of Postfix child processes that provide a given service.

• Max number of addresses remembered by the duplicate filter: limits the number of addresses remembered by the duplicate filter for alias, virtual, etc. expansion.

• Max attempts to acquire file lock: limits the number of attempts to acquire anexclusive lock on a mailbox or other file.

• Time in seconds between file lock attempts: sets the time in seconds betweenattempts to acquire an exclusive lock.

• Max attempts to fork a process: limits the number of attempts to fork a process.• Time in seconds between fork attempts: sets the time in seconds between fork

attempts.•

Max memory used for processing headers: limits the amount of memory in bytesused for processing a message header. If a header is larger, the remainder of theentire message is treated as message body.



• Max memory used for handling input lines: limits the amount of memory in bytesused for handling input lines. Longer lines are chopped up into pieces andreconstructed upon delivery.

• Max size of a message: limits the total size in bytes of a message, includingenvelope information.

• Max number of messages in the active queue: limits the number of messages in

the active queue.• Max number of in-memory recipients: limits the number of in-memory recipients.

It also limits the size of the short-term, in-memory destination status cache.• Min free space in the queue file system: specifies the minimal amount of free

space in bytes in the queue file system. This is currently used by the SMTP server to decide if it will accept any mail at all.

• Max time after which stale lock is released: limits the time after which a stalelock is removed. This is used for delivery to file or mailbox.

• Time in seconds between attempts to contact a broken MDT: specifies the timein seconds between attempts by the queue manager to contact a broken messagedelivery transport.

• Max size of a mailbox: limits the total size in bytes of a mailbox, in other words theinbox for a user.


SMTP server options

The SMTP server accepts network connection requests and performs zero or more SMTPtransactions per connection. Each received message is piped through the cleanupdaemon, and is placed into the incoming queue as one single queue file.

• SMTP greeting banner: specifies the text that follows the 220 status code in theSMTP greeting banner. Some people like to see the mail version advertised. By

default, Postfix shows no version.• Max number of recipients accepted for delivery: restricts the number of

recipients that the SMTP server accepts per message delivery.



• Disable SMTP VRFY command: disable the SMTP VRFY command. This stops

some techniques used by spammers to harvest email addresses.• Timeout in seconds for SMTP transactions: limits the time in seconds to send an

SMTP server response and to receive an SMTP client request.• Timeout before sending 4xx/5xx error response: specifies the time in seconds

the SMTP server waits before sending a 4xx or 5xx SMTP server error response.

This prevents naive clients from going into an error - disconnect - connect - error loop.

• Error count for temporarily ignore a client: specifies an error count lower limit.When an SMTP client has made this number of errors within a session, the server waits error_count seconds before responding to any client request.

• Error count for closing connection: specifies an error count upper limit. TheSMTP server disconnects after an SMTP client makes this number of errors within asession.

• HELO is required: optionally turns on the requirement that SMTP clients mustintroduce themselves at the beginning of an SMTP session. Requiring this will stopsome UCE (unsolicited commercial email) software.

• Allow untrusted routing: controls if Postfix will forward mail with sender-specifiedrouting (user[@%!]remote[@%!]site) from untrusted clients to destinations

that are blessed by the relay_domains parameter. By default, untrusted clients

are not allowed to specify routing.• Restrict ETRN command upon...: restricts what clients are allowed to issue the

ETRN command. The present Postfix ETRN differs from other ETRN

implementations in that it flushes mail for all destinations. This will change in thefuture. The default is to allow ETRN from any host.

• Restrictions on client hostnames/addresses: specifies optional restrictions onSMTP client host names and addresses. The default is to allow connections from

any host.• Restrictions on sends in HELO commands: specifies optional restrictions on what

SMTP clients can send in SMTP HELO and EHLO commands. The default is to

permit everything.• Restrictions on sender addresses: specifies optional restrictions on sender

addresses that SMTP clients can send in MAIL FROM commands. The default is topermit any sender address.

• Restrictions on recipient addresses: specifies restrictions on recipient addressesthat SMTP clients can send in RCPT TO commands.

• DNS domains for blacklist lookups: specifies an optional list of DNS domains thatpublish the network addresses of blacklisted hosts. By default, RBL blacklistlookups are disabled.

• Restrict mail relaying: restricts what client hostname domains (and subdomainsthereof) this mail system will relay mail from, and restricts what destination domains(and subdomains thereof) this system will relay mail to.

• SMTP server response on access map violation: specifies the SMTP server response code when a mail violates the access map restriction that is: Accessdenied: access_map violation (on SMTP client or HELO hostname, sender or recipient email address).

• SMTP server response on invalid hostname reject: specifies the SMTP server response code when a client violates the reject_invalid_hostname anti-UCE

restriction rule that is: Bad syntax for client HELO hostname (Not RFC compliant).• SMTP server response on RBL domains violation: specifies the SMTP server

response code when a mail violates the maps_rbl_domains rule that is: Access



denied: SMTP client listed in RBL.• SMTP server response on forbidden relaying: specifies the SMTP server

response code when a mail violates the relay_domains_reject rule that is:

Access denied: Relay not authorized or not local host not a gateway.• SMTP server response on unknown domain reject: specifies the SMTP server

response code when a client violates the reject_unknown_sender_domainor

reject_unknown_recipient_domain restriction rules that are: Access denied:Unknown domain for sender or recipient email address (without DNS A or MXrecord)

• SMTP server response on unknown domain reject: specifies the SMTP server response code when a client violates the reject_unknown_sender_domainor

reject_unknown_recipient_domain restriction rules that are: Access denied:

Unknown domain for sender or recipient email address (without DNS A or MXrecord)

• SMTP server response on unknown client reject: specifies the SMTP server response code when a client without address to name mapping violates the

reject_unknown_clients restriction rule that is: Access denied: UnknownSMTP client hostname (without DNS A or MX record).• SMTP server response on unknown hostname reject: specifies the SMTP server

response code when a client violates the reject_unknown_hostname restriction

rule that is: Access denied: Unknown client HELO hostname (without DNS A or MXrecord).


SMTP client options

The SMTP client processes message delivery requests from the queue manager. Eachrequest specifies a queue file, a sender address, a domain or host to deliver to, andrecipient information.

• Action when listed as best MX host: controls what happens when the localsystem is listed as the best MX host for a destination. By default, Postfix reports a"mail loops back to myself" error and bounces the message.

• Hosts/domains to hand off mail to on invalid destination: specifies zero or morehosts or domains to hand off mail to if a message destination is not found, or if adestination is unreachable.

• Ignore MX lookup error: controls what happens when a name server fails torespond to an MX lookup request.

• Skip wait for the QUIT command: controls whether the SMTP client waits for the



response to the QUIT command. The default is not to wait.

• Max number of parallel deliveries to the same destination: limits the number of parallel deliveries to the same destination via the smtp delivery agent.

• Max number of recipients per delivery: limits the number of recipients per delivery via the smtp delivery agent.

• Timeout for completing TCP connections: specifies the SMTP client timeout in

seconds for completing a TCP connection.• Timeout on waiting for answer to MAIL FROM: specifies the SMTP client timeout

in seconds for sending the SMTP MAIL FROM command, and for receiving theserver response.

• Timeout on waiting for answer to DATA: specifies the SMTP client timeout inseconds for sending the SMTP DATA command, and for receiving the server response.

• Timeout on waiting for answer to ending ".": specifies the SMTP client timeout inseconds for sending the SMTP ".", and for receiving the server response.

• Skip 4xx greeting: controls what happens when an SMTP server greets us with a4XX status code.

• Timeout on waiting for the greeting banner: specifies the SMTP client timeout inseconds for receiving the SMTP greeting banner.

• Timeout on waiting for answer to RCPT TO: specifies the SMTP client timeout inseconds for sending the SMTP RCPT TO command, and for receiving the server response.

• Timeout on waiting for answer to transmit of message content: specifies theSMTP client timeout in seconds for sending the SMTP message content.

• Timeout on waiting for answer to QUIT: specifies the SMTP client timeout inseconds for sending the SMTP QUIT command, and for receiving the server response.


Delivery rates

This parameter controls the number of concurrent processes that implement a Postfixservice (smtp client, smtp server, local delivery, etc.).

• Max number of parallel deliveries to the same destination: specifies a defaultlimit on the number of parallel deliveries to the same destination. This is the defaultlimit for delivery via SMTP, via the local delivery agent and via the pipe mailer.

• Max number of recipients per message delivery: specifies a default limit on thenumber of recipients per message delivery. This is the default limit for delivery viaSMTP, via the local delivery agent and via the pipe mailer.

• Initial concurrency level for delivery to the same destination: specifies theinitial per-destination concurrency level for parallel delivery to the same destination.

This limit applies to delivery via SMTP, via the local delivery agent and via the pipemailer.

• Max time in queue before message is undeliverable: specifies the maximal time



in days a message is queued before it is sent back as undeliverable.• Min time between attempts to deliver a deferred message: specifies the minimal

time in seconds between attempts to deliver a deferred message. This parameter also limits the time an unreachable destination is kept in the short-term, in-memorydestination status cache.

• Max time between attempts to deliver a deferred message: specifies the

maximal time in seconds between attempts to deliver a deferred message.• Time (secs) between scanning the deferred queue: specifies the time in seconds

between deferred queue scans by the queue manager.• Transports that should not be delivered: specifies the names of transports that

should not be delivered to unless someone issues "sendmail -q" or equivalent.


Debugging features

You can ask Postfix to produce mail delivery reports for debugging purposes. These

reports not only show sender/recipient addresses after address rewriting and aliasexpansion or forwarding, they also show information about delivery to mailbox, delivery tonon-Postfix command, responses from remote SMTP servers, and so on.

• List of domain/network patterns for which verbose log is enabled: specifies anoptional list of domain or network patterns, /file/name patterns or type:name tables.When an SMTP client or server host name or address matches a pattern, increase

the verbose logging level by the amount specified in the debug_peer_levelparameter.

• Verbose logging level when matching the above list: specifies the increment inverbose logging level when an SMTP client or server host name or addressmatches a pattern in the debug_peer_list parameter.


Server Processes

This option can be used to manage the various server processes used by Postfix for

receiving and processing email. Unless you are an expert in Postfix configuration theyshould not generally be edited, however you want want to enable or disable certain server processes to turn on and off Postfix features like SMTP over SSL.



To create new server process click on the Add a new server process button. Fill the formthat appears:

Click Create to preserve.

LDAP lookups

The Postfix mail system uses optional tables for address rewriting or mail routing. Thesetables are usually in dbm or db format. Alternatively, lookup tables can be specified asLDAP databases. Postfix can use an LDAP directory as a source for any of its lookups:aliases, virtual, canonical, etc. This allows you to keep information for your mail service ina replicated network database with fine-grained access controls.

Mail Queue

Postfix has four different queues: maildrop, incoming, active, deferred . Locally-postedmail is deposited into the maildrop, and is copied to the incoming queue after somecleaning up. The incoming queue is for mail that is still arriving or that the queuemanager hasn't looked at yet. The active queue is a limited-size queue for mail that thequeue manager has opened for delivery. Mail that can't be delivered goes to the deferredqueue, so that it does not get in the way of other deliveries.

Configuration Check

This page allows to check main Postfix options.



User Mailboxes

Click the User Mailboxes icon and you will see the page, that contains the user mailboxeslist:

To get access to mails in these mailboxes, just click one of mailboxes names in this list.To read mail in some file enter the name to this file or click the "..." button and find it in the

pop-up window.

Postfix Configuration

Documents