Configure mail virtual hosts with the Postoffice SMTP Daemon

Pierre-Philipp Braun <pbraun@nethence.com>

Introduction

mbox may be the most convenient mailbox format, it's just bare text files. Combined with virtual hosts, we also establish a clean cut separation between the domains, and users.

Ref. www.washington.edu/imap/documentation/formats.txt.html

POP is a nice protocol for users, it may even be used somehow like IMAP : configure your client to keep the messages on the server and remove if deleted from INBOX. You keep a full copy of the message locally and it only fetches the mail once; much lighter than IMAP.

Note. we're using Postoffice and vm-pop3d but Postfix and Dovecot are also vhost mbox capable (unixdoc.ua-i.net/articles/mail/postfix/virtual-hostsninstall.txt).

Note. Postoffice compiles fine on NetBSD/sparc64 since 1.2.0 and 1.3.pre1 fixed the mail/aliases path. No additionnal tweeks are needed since then.

Prepare the system

Check if mail user and group exist. Note the shell should be /sbin/nologin,

grep mail /etc/passwd

grep mail /etc/group

If they don't exist, create them,

groupadd mail

useradd -g mail -s /sbin/nologin mail

Then prepare directories and permissions,

mkdir /var/spool/virtual

mkdir /var/spool/mqueue

mkdir /etc/virtual

chown mail:mail /var/spool/virtual

chown mail:mail /var/spool/mqueue

chown mail:mail /etc/virtual

chmod 700 /var/spool/virtual

chmod 700 /var/spool/mqueue

chmod 700 /etc/virtual

Install vm-pop3d

Ge the latest tarball from this address: www.reedmedia.net/software/virtualmail-pop3d/#download

Untar the tarball and,

./configure --help

./configure --enable-virtual

make clean

make

su

make install

Start the daemon,

/usr/local/sbin/vm-pop3d -umail -gmail -d2

Install postoffice

Check for those dependencies,

- ndbm or gdbm (on RHEL add gdbm-devel)

- tcpwrappers (eventually)

Get the latest tarball from this address : www.tsfr.org/~orc/Code/postoffice/

Untar the tarball and,

./configure.sh --help

./configure.sh \

--with-auth \

--with-milter \

--with-vhost=/etc/virtual \

--with-vspool=/var/spool/virtual \

--with-vuser=mail

make clean

make

su

make install

Note if you like to enable non virtual host AUTH LOGIN, also add,

--with-auth=passwd

Those options may also be worth mentioning but I don't use them,

--use-mailwrappers \

--with-tcpwrappers \

--with-greylist \

Note. --with-auth does SMTP Authentication, AUTH LOGIN. No need for cyrus-sasl kluges & pain like other SMTP servers do. No configuration is needed, it just works for virtual host users even.

Note. --with-milter permits to use Milters (www.milter.org/)

Note. this was alright for Postoffice 1.2.x and 1.3.x. Maybe there some new relevant options. Check with,

./configure --help

Update mailwrapper's config,

vi /etc/mailer.conf

And eventually,

cd /usr/bin

mv mailq mailq.old

ln -s /usr/local/bin/mailq

Configure Postoffice

Edit Postoffice's configuration,

vi /etc/postoffice.cf

For example

self=mx.example.com

audit

clients=30

delay=1m

hops=3

minfree=400m

size=10m

timeout=1h

escape-from=1

Check the manuals for other options.

As for milters, here's two examples,

filter=/path/to/unix.socket

filter=hostname:port

Edit the global aliases and update the alias table,

vi /etc/mail/aliases (or /etc/aliases, eventually link one to another)

newaliases

Start the daemon,

/usr/local/lib/postoffice -C/etc/postoffice.cf -bd -q2

Note. you can put a higher or lower value than 2 minutes (-q2) for the queue processing interval.

This magnificiently results in two processes (do ps aux):

postoffice: postoffice: accepting connections

postoffice: postoffice: runq every 2 minutes

To check queue,

mailq

To check current SMTP sessions,

ps aux | grep postoffice

To force the immediate processing of the queue,

runq

Edit the virtual hosts,

vi /etc/virtual/domains.cf

Edit password files with pop_passwd.pl or vpasswd

pop_passwd.pl username password >> example.com/passwd

vi example.com/aliases

newaliases example.com

pop_passwd.pl : pbraun.nethence.com/balls/mail/pop_passwd.pl

vpasswd wasn't easy to install, but if you prefer C than perl, www.pell.portland.or.us/%7Eorc/Code/post/

MX records & name resolution

Note. Postoffice skips /etc/hosts and system DNS resolution. It has its own.

Virtual vs non-Virtual

Note. If the receiving message is for another domain than those listed in domains.cf, namely the virtual ones, it will accept them locally as long as the MX record matches or is empty.

Note. When doing SMTP through telnet, you need to embrace the IP like,

rcpt to:user@[XX.XX.XX.XX]

Troubbleshooting

Check you got the latest version,

/usr/local/lib/postoffice -V

Check the postoffice running processes,

ps aux | grep post

ps aux | grep runq

Check and run the queue,

mailq

cd /var/spool/mqueue/

ls -l

ps aux | grep post

ps aux | grep runq

runq

Find out what's using /var/spool/mqueue (in case it's not even a lying runq process),

lsof | grep mqueue

Migrating the whole service to another server

When migrating the SMTP service from one server to another (not mentioning the DNS matters),

cd /var/spool

ls -l mqueue  # should be empty.  Otherwise do mailq

tar czpf /root/virtualVAR.tar.gz virtual

cd /etc

tar czpf /root/virtualETC.tar.gz virtual

Send both to your new server, check /etc/mailer.conf, /etc/aliases (or /etc/mail/aliases),

and refresh the alias tables,

newaliases

newaliases example.com

Links

Postoffice : www.tsfr.org/~orc/Code/postoffice/

Milter : www.milter.org/

pop_passwd.pl : pbraun.nethence.com/balls/mail/pop_passwd.pl

vpasswd: www.pell.portland.or.us/%7Eorc/Code/post/

vm-pop3d : www.reedmedia.net/software/virtualmail-pop3d/

Auth login : www.faqs.org/rfcs/rfc2554.html

Postfix : www.postfix.org/ www.postfix.org/VIRTUAL_README.html#virtual_mailbox

Dovecot : www.dovecot.org/

Mailbox formats : www.washington.edu/imap/documentation/formats.txt.html

Milters : www.milter.org/

Page generated Mon Aug 18 12:05:30 CEST 2008 html/css
Pierre-Philipp Braun <pbraun@nethence.com>
BSD Documentation Licence