# Setting up mail server behind a router

## MacMasta

I'm trying to set up a general-purpose mailserver behind a little linksys router - so I install postfix, (good start!) and jimmy the config file around so it works.

The trick is this - because it's behind the router, the dns thing is a little sketchy - I've got ports 22 (ssh), 80 (http) and 110 (which, I think, is incoming mail) forwarded to the mahcine. Of course, it thinks it's 192.168.1.50, and the rest of the world knows it as another IP, (which has a dyns.cx hostname hooked to it) 

Local mail delivery and sending mail work just fine, but mail is not recieved - and (because I don't have log access on the machine I'm sending from to test it) I can't figure out what's going on.

/etc/postfix/main.cf is posted below - anything I forgot to do, or anything jump out as an obvious mistake?

(Pardon the length)

Thanks!

```

# $Header: /home/cvsroot/gentoo-x86/net-mail/postfix/files/main.cf,v 1.3 2002/05                                                                                   

/04 03:55:29 woodchip Exp $

#

# Global Postfix configuration file. This file lists only a subset

# of all 100+ parameters. See the sample-xxx.cf files for a full list.

# 

# The general format is lines with parameter = value pairs. Lines

# that begin with whitespace continue the previous line. A value can

# contain references to other $names or ${name}s.

#

# SOFT BOUNCE

#

# The soft_bounce parameter provides a limited safety net for

# testing.  When soft_bounce is enabled, mail will remain queued that

# would otherwise bounce. This parameter disables locally-generated

# bounces, and prevents the SMTP server from rejecting mail permanently

# (by changing 5xx replies into 4xx replies). However, soft_bounce

# is no cure for address rewriting mistakes or mail routing mistakes.

#

#soft_bounce = no

# LOCAL PATHNAME INFORMATION

#

# The queue_directory specifies the location of the Postfix queue.

# This is also the root directory of Postfix daemons that run chrooted.

# See the files in examples/chroot-setup for setting up Postfix chroot

# environments on different UNIX systems.

#

queue_directory = /var/spool/postfix

# The command_directory parameter specifies the location of all

# postXXX commands.  The default value is $program_directory.

#

command_directory = /usr/sbin

# The daemon_directory parameter specifies the location of all Postfix

# daemon programs (i.e. programs listed in the master.cf file). The

# default value is $program_directory. This directory must be owned

# by root.

#

daemon_directory = /usr/lib/postfix

# QUEUE AND PROCESS OWNERSHIP

#

# The mail_owner parameter specifies the owner of the Postfix queue

# and of most Postfix daemon processes.  Specify the name of a user

# account THAT DOES NOT SHARE A GROUP WITH OTHER ACCOUNTS AND THAT

# OWNS NO OTHER FILES OR PROCESSES ON THE SYSTEM.  In particular,

# don't specify nobody or daemon. PLEASE USE A DEDICATED USER.

#

mail_owner = postfix

# The default_privs parameter specifies the default rights used by

# the local delivery agent for delivery to external file or command.

# These rights are used in the absence of a recipient user context.

# DO NOT SPECIFY A PRIVILEGED USER OR THE POSTFIX OWNER.

#

#default_privs = nobody

# INTERNET HOST AND DOMAIN NAMES

# 

# The myhostname parameter specifies the internet hostname of this

# mail system. The default is to use the fully-qualified domain name

# from gethostname(). $myhostname is used as a default value for many

# other configuration parameters.

#

#myhostname = host.domain.name

#myhostname = virtual.domain.name

# The mydomain parameter specifies the local internet domain name.

# The default is to use $myhostname minus the first component.

# $mydomain is used as a default value for many other configuration

# parameters.

#

#mydomain = domain.name

# SENDING MAIL

# 

# The myorigin parameter specifies the domain that locally-posted

# mail appears to come from. The default is to append $myhostname,

# which is fine for small sites.  If you run a domain with multiple

# machines, you should (1) change this to $mydomain and (2) set up

# a domain-wide alias database that aliases each user to

# user@that.users.mailhost.

#

#myorigin = $myhostname

#myorigin = $mydomain

# RECEIVING MAIL

# The inet_interfaces parameter specifies the network interface

# addresses that this mail system receives mail on.  By default,

# the software claims all active interfaces on the machine. The

# parameter also controls delivery of mail to user@[ip.address].

#

inet_interfaces = all

#net_interfaces = $myhostname

#inet_interfaces = $myhostname, localhost

# The mydestination parameter specifies the list of domains that this

# machine considers itself the final destination for. That does not

# include domains that are hosted on this machine. Those domains are

# specified elsewhere (see sample-virtual.cf, and sample-transport.cf).

#

# The default is $myhostname + localhost.$mydomain.  On a mail domain

# gateway, you should also include $mydomain. Do not specify the

# names of domains that this machine is backup MX host for. Specify

# those names via the relay_domains or permit_mx_backup settings for

# the SMTP server (see sample-smtpd.cf.

#

# The local machine is always the final destination for mail addressed

# to user@[the.net.work.address] of an interface that the mail system

# receives mail on (see the inet_interfaces parameter).

#

# Specify a list of host or domain names, /file/name or type:table

# patterns, separated by commas and/or whitespace. A /file/name

# pattern is replaced by its contents; a type:table is matched when

# a name matches a lookup key.  Continue long lines by starting the

# next line with whitespace.

#

# DO NOT LIST VIRTUAL DOMAINS HERE. LIST THEM IN THE VIRTUAL FILE

# INSTEAD. BE SURE TO READ THE ENTIRE VIRTUAL MANUAL PAGE.

#

mydestination = $myhostname, localhost.$mydomain

#mydestination = $myhostname, localhost.$mydomain $mydomain

#mydestination = $myhostname, localhost.$mydomain, $mydomain,

#       mail.$mydomain, www.$mydomain, ftp.$mydomain

# INTERNET OR INTRANET

# The relayhost parameter specifies the default host to send mail to

# when no entry is matched in the optional transport(5) table. When

# no relayhost is given, mail is routed directly to the destination.

#

# On an intranet, specify the organizational domain name. If your

# internal DNS uses no MX records, specify the name of the intranet

# gateway host instead.

#

# In the case of SMTP, specify a domain, host, host:port, [host]:port,

# [address] or [address]:port; the form [host] turns off MX lookups.

# If you specify multiple SMTP destinations, Postfix will try them

# in the specified order.

#

# If you're connected via UUCP, see also the default_transport parameter.

#

# relayhost = $mydomain

# relayhost = gateway.my.domain

# relayhost = uucphost

# relayhost = [an.ip.add.ress]

# REJECTING UNKNOWN LOCAL USERS

#

# The local_recipient_maps parameter specifies optional lookup tables

# with all users that are local with respect to $mydestination and

# $inet_interfaces.  If this parameter is defined, then the SMTP server

# will reject mail for unknown local users.

#

# The local_recipient_maps parameter accepts tables with bare usernames

# such as unix:passwd.byname and alias maps.

#

# Beware: if the Postfix SMTP server runs chrooted, you may have to

# copy the passwd database into the jail. This is system dependent.

#

# FOR THIS TO WORK, DO NOT SPECIFY VIRTUAL DOMAINS IN MYDESTINATION.

# MYDESTINATION MUST LIST NON-VIRTUAL DOMAINS ONLY.

#

#local_recipient_maps = $alias_maps unix:passwd.byname

# ADDRESS REWRITING

#

# Insert text from sample-rewrite.cf if you need to do address

# masquerading.

#

# Insert text from sample-canonical.cf if you need to do address

# rewriting, or if you need username->Firstname.Lastname mapping.

# ADDRESS REDIRECTION (VIRTUAL DOMAIN)

#

# Insert text from sample-virtual.cf if you need virtual domain support.

# "USER HAS MOVED" BOUNCE MESSAGES

#

# Insert text from sample-relocated.cf if you need "user has moved"

# style bounce messages. Alternatively, you can bounce recipients

# with an SMTP server access table. See sample-smtpd.cf.

# TRANSPORT MAP

#

# Insert text from sample-transport.cf if you need explicit routing.

# ALIAS DATABASE

#

# The alias_maps parameter specifies the list of alias databases used

# by the local delivery agent. The default list is system dependent.

# On systems with NIS, the default is to search the local alias

# database, then the NIS alias database. See aliases(5) for syntax

# details.

# 

# If you change the alias database, run "postalias /etc/aliases" (or

# wherever your system stores the mail alias file), or simply run

# "newaliases" to build the necessary DBM or DB file.

#

# It will take a minute or so before changes become visible.  Use

# "postfix reload" to eliminate the delay.

#

#alias_maps = dbm:/etc/aliases

#alias_maps = hash:/etc/aliases

#alias_maps = hash:/etc/aliases, nis:mail.aliases

#alias_maps = netinfo:/aliases

alias_maps = hash:/etc/mail/aliases

# The alias_database parameter specifies the alias database(s) that

# are built with "newaliases" or "sendmail -bi".  This is a separate

# configuration parameter, because alias_maps (see above) may specify

# tables that are not necessarily all under control by Postfix.

#

#alias_database = dbm:/etc/aliases

#alias_database = dbm:/etc/mail/aliases

#alias_database = hash:/etc/aliases

#alias_database = hash:/etc/aliases, hash:/opt/majordomo/aliases

alias_database = hash:/etc/mail/aliases

# ADDRESS EXTENSIONS (e.g., user+foo)

#

# The recipient_delimiter parameter specifies the separator between

# user names and address extensions (user+foo). See canonical(5),

# local(8), relocated(5) and virtual(5) for the effects this has on

# aliases, canonical, virtual, relocated and .forward file lookups.

# Basically, the software tries user+foo and .forward+foo before

# trying user and .forward.

#

# recipient_delimiter = +

# DELIVERY TO MAILBOX

#

# The home_mailbox parameter specifies the optional pathname of a

# mailbox file relative to a user's home directory. The default

# mailbox file is /var/spool/mail/user or /var/mail/user.  Specify

# "Maildir/" for qmail-style delivery (the / is required).

#

#home_mailbox = Mailbox

#home_mailbox = Maildir/

home_mailbox = .maildir/

 

# The mail_spool_directory parameter specifies the directory where

# UNIX-style mailboxes are kept. The default setting depends on the

# system type.

#

# mail_spool_directory = /var/mail

# mail_spool_directory = /var/spool/mail

# The mailbox_command parameter specifies the optional external

# command to use instead of mailbox delivery. The command is run as

# the recipient with proper HOME, SHELL and LOGNAME environment settings.

# Exception:  delivery for root is done as $default_user.

#

# Other environment variables of interest: USER (recipient username),

# EXTENSION (address extension), DOMAIN (domain part of address),

# and LOCAL (the address localpart).

#

# Unlike other Postfix configuration parameters, the mailbox_command

# parameter is not subjected to $parameter substitutions. This is to

# make it easier to specify shell syntax (see example below).

#

# Avoid shell meta characters because they will force Postfix to run

# an expensive shell process. Procmail alone is expensive enough.

#

# IF YOU USE THIS TO DELIVER MAIL SYSTEM-WIDE, YOU MUST SET UP AN

# ALIAS THAT FORWARDS MAIL FOR ROOT TO A REAL USER.

#

#mailbox_command = /some/where/procmail

#mailbox_command = /some/where/procmail -a "$EXTENSION"

# The mailbox_transport specifies the optional transport in master.cf

# to use after processing aliases and .forward files. This parameter

# has precedence over the mailbox_command, fallback_transport and

# luser_relay parameters.

#

# Specify a string of the form transport:nexthop, where transport is

# the name of a mail delivery transport defined in master.cf.  The

# :nexthop part is optional. For more details see the sample transport

# configuration file.

#

#mailbox_transport = lmtp:unix:/file/name

#mailbox_transport = cyrus

# The fallback_transport specifies the optional transport in master.cf

# to use for recipients that are not found in the UNIX passwd database.

# This parameter has precedence over the luser_relay parameter.

#

# Specify a string of the form transport:nexthop, where transport is

# the name of a mail delivery transport defined in master.cf.  The

# :nexthop part is optional. For more details see the sample transport

# configuration file.

#

#fallback_transport = lmtp:unix:/file/name

#fallback_transport = cyrus

#fallback_transport =

# The luser_relay parameter specifies an optional destination address

# for unknown recipients.  By default, mail for unknown local recipients

# is bounced.

#

# The following expansions are done on luser_relay: $user (recipient

# username), $shell (recipient shell), $home (recipient home directory),

# $recipient (full recipient address), $extension (recipient address

# extension), $domain (recipient domain), $local (entire recipient

# localpart), $recipient_delimiter. Specify ${name?value} or

# ${name:value} to expand value only when $name does (does not) exist.

#

# luser_relay = $user@other.host

# luser_relay = $local@other.host

# luser_relay = admin+$local

  

# JUNK MAIL CONTROLS

# 

# The controls listed here are only a very small subset. See the file

# sample-smtpd.cf for an elaborate list of anti-UCE controls.

# The header_checks parameter restricts what may appear in message

# headers. This requires that POSIX or PCRE regular expression support

# is built-in. Specify "/^header-name: stuff you do not want/ REJECT"

# in the pattern file. Patterns are case-insensitive by default. Note:

# specify only patterns ending in REJECT (reject entire message) or

# IGNORE (silently discard this header). Patterns ending in OK are

# mostly a waste of cycles.

#

#header_checks = regexp:/etc/postfix/filename

#header_checks = pcre:/etc/postfix/filename

# The relay_domains parameter restricts what clients this mail system

# will relay mail from, or what destinations this system will relay

# mail to.  See the smtpd_recipient_restrictions restriction in the

# file sample-smtpd.cf.

#

# By default, Postfix relays mail

# - from trusted clients whose IP address matches $mynetworks, 

# - from trusted clients matching $relay_domains or subdomains thereof,

# - from untrusted clients to destinations that match $relay_domains

#   or subdomains thereof, except addresses with sender-specified routing.

# The default relay_domains value is $mydestination.

# 

# In addition to the above, the Postfix SMTP server by default accepts mail

# that Postfix is final destination for:

# - destinations that match $inet_interfaces,

# - destinations that match $mydestination

# - destinations that match $virtual_maps.

# These destinations do not need to be listed in $relay_domains.

# 

# Specify a list of hosts or domains, /file/name patterns or type:name

# lookup tables, separated by commas and/or whitespace.  Continue

# long lines by starting the next line with whitespace. A file name

# is replaced by its contents; a type:name table is matched when a

# (parent) domain appears as lookup key.

#

# NOTE: Postfix will not automatically forward mail for domains that

# list this system as their primary or backup MX host. See the

# permit_mx_backup restriction in the file sample-smtpd.cf.

#

#relay_domains = $mydestination

# The mynetworks parameter specifies the list of networks that are

# local to this machine.  The list is used by the anti-UCE software

# to distinguish local clients from strangers. See permit_mynetworks

# and smtpd_recipient_restrictions in the file sample-smtpd.cf file.

#

# The default is a list of all networks attached to the machine:  a

# complete class A network (X.0.0.0/8), a complete class B network

# (X.X.0.0/16), and so on. If you want stricter control, specify a

# list of network/mask patterns, where the mask specifies the number

# of bits in the network part of a host address. You can also specify

# the absolute pathname of a pattern file instead of listing the

# patterns here.

#

#mynetworks = 168.100.189.0/28, 127.0.0.0/8

#mynetworks = $config_directory/mynetworks

# FAST ETRN SERVICE

#

# Postfix maintains per-destination logfiles with information about

# deferred mail, so that mail can be flushed quickly with the SMTP

# "ETRN domain.name" command, or by executing "sendmail -qRdomain.name".

# 

# By default, Postfix maintains deferred mail logfile information

# only for destinations that Postfix is willing to relay to (as

# specified in the relay_domains parameter). For other destinations,

# Postfix attempts to deliver ALL queued mail after receiving the

# SMTP "ETRN domain.name" command, or after execution of "sendmail

# -qRdomain.name". This can be slow when a lot of mail is queued.

# 

# The fast_flush_domains parameter controls what destinations are

# eligible for this "fast ETRN/sendmail -qR" service.

# 

#fast_flush_domains = $relay_domains

#fast_flush_domains =

# SHOW SOFTWARE VERSION OR NOT

#

# The smtpd_banner parameter specifies the text that follows the 220

# code in the SMTP server's greeting banner. Some people like to see

# the mail version advertised. By default, Postfix shows no version.

#

# You MUST specify $myhostname at the start of the text. That is an

# RFC requirement. Postfix itself does not care.

#

#smtpd_banner = $myhostname ESMTP $mail_name

#smtpd_banner = $myhostname ESMTP $mail_name ($mail_version)

# PARALLEL DELIVERY TO THE SAME DESTINATION

#

# How many parallel deliveries to the same user or domain? With local

# delivery, it does not make sense to do massively parallel delivery

# to the same user, because mailbox updates must happen sequentially,

# and expensive pipelines in .forward files can cause disasters when

# too many are run at the same time. With SMTP deliveries, 10

# simultaneous connections to the same domain could be sufficient to

# raise eyebrows.

# 

# Each message delivery transport has its XXX_destination_concurrency_limit

# parameter.  The default is $default_destination_concurrency_limit.

local_destination_concurrency_limit = 2

default_destination_concurrency_limit = 10

# DEBUGGING CONTROL

#

# The debug_peer_level parameter specifies the increment in verbose

# logging level when an SMTP client or server host name or address

# matches a pattern in the debug_peer_list parameter.

#

debug_peer_level = 2

# The debug_peer_list parameter specifies an optional 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_level parameter.

#

# debug_peer_list = 127.0.0.1

# debug_peer_list = some.domain

# The debugger_command specifies the external command that is executed

# when a Postfix daemon program is run with the -D option.

#

# Use "command .. & sleep 5" so that the debugger can attach before

# the process marches on. If you use an X-based debugger, be sure to

# set up your XAUTHORITY environment variable before starting Postfix.

#

debugger_command =

         PATH=/usr/bin:/usr/X11R6/bin

         xxgdb $daemon_directory/$process_name $process_id & sleep 5

# Other configurable parameters.

```

[/code]

----------

## MacMasta

For those who are looking for an answer:

forward port 25, not 110.

That's all it took.

~Mac~

----------

## Digiman

Did you have to change anything with your main.cf to fix it as well? Or are you using the posted config exactly as shown?

Thank you,

Digiman

----------

## MacMasta

Just Like That.

~Mac~

----------

