Virtual Mail Domain User's Guide

• Overview
• Other Virtual Mail Resources
• Files
  • /etc/buildvirtual
  • /etc/makevirtual
  • /etc/virtualdomains.conf
  • /etc/virtualdomains
  • /etc/virtualdomains.db
  • ~/username/domainname.email
• Setup
  • Sendmail Configuration
  • Installing Files
  • Crontab Entry
• Configuration
  • Site Specific Configuration
  • Adding a Virtual Email Domain
  • Suggested DNS configurations
  • Considerations for Alternate Configurations
• End User Configuration
  • The End User Configuration File
  • Rules for Creating Mapings
  • Explanation of Error Messages

For those of us who weren't at class yesterday, virtual mail allows us to create a sort of forwarding table, that lets us map email addresses at a virtual domain to addresses elsewhere on the Internet. This allows us to do the following:

Say I have the domain `halo.net` (which I do), and I want to give all my friends email addresses @halo.net. I can't offer them accounts on the system, because I have too many friends and my computer isn't that big, but thats ok, because they already have too many accounts.

For our example, lets say I've got 5 friends who want to have @halo.net email addresses. Their email addresses are as follows:

• winter@jurai.net
• zakk@intersurf.com
• coneill@oneill.net
• grendel@netaxs.com
• abbyfg@tezcat.com

Each of these users wants their email address to be:

• winter -> winter@halo.net
• zakk -> zakk@halo.net
• coneill -> qwerty@halo.net
• grendel -> siva@halo.net
• abbyfg -> huaman@halo.net

I've written a simple system that allows virtual domain customers to manage their own mappings. It preforms sanity checking on the configuration files and allows users to be notified via email of configuration errors.

Other Virtual Mail Resources

Note that /etc/makevirtual contains site specific configuration items that muct be changed in order for it to operate correctly.

/etc/virtualdomains.conf

LOCAL_CONFIG
Kmaildomains hash /etc/virtualdomains.db


LOCAL_RULE_0
R$+ < @ $+ . >          $: $1 < @ $2 > .
R$+ < @ $+ > $*         $: $(maildomains $1@$2 $: $1 < @ $2 > $3 $)
R$+ < @ $+ > $*         $: $(maildomains $2 $: $1 < @ $2 > $3 $)
R$+ < @ $+ > .          $: $1 < @ $2 . >

Kmaildomains hash /etc/virtualdomains.db

R$+ < @ $+ . >          $: $1 < @ $2 > .
R$+ < @ $+ > $*         $: $(maildomains $1@$2 $: $1 < @ $2 > $3 $)
R$+ < @ $+ > $*         $: $(maildomains $2 $: $1 < @ $2 > $3 $)
R$+ < @ $+ > .          $: $1 < @ $2 . >

• buildvirtual
• makevirtual
• virtualdomains.conf

0       *       *       *       *       root    /etc/buildvirtual

$this_host = "jurai.net";
$SENDMAIL = "/usr/sbin/sendmail";
$m_fullname = "Virtual Domains Subsystem Daemon";
$m_from = "virtual-domains\@intersurf.com";

halo.net	halo	/h0/halo/halo.email

halo.net	IN	MX	10 sasami.jurai.net.
halo.net	IN	MX	20 dim.intersurf.net.

The config file has only two elements per line. A username and a valid Internet email address. By valid I mean an email address that is delivered to a shell or POP email account.

Continuing the above example, I would add the following to /h0/halo/halo.email:

winter	winter@jurai.net
zakk	zakk@intersurf.com
qwerty	coneill@oneill.net
siva	grendel@netaxs.com
huaman	abbyfg@tezcat.com

• All invalid mappings will not be processed.
• The username and email addresses must be valid, with no strange illegal characters in them.
• A valid username does not have the '@' symbol in it.
• A valid email address has an '@' symbol in it.
• Address loops are not allowed. Specifying an email address at the virtual domain you are remapping is not allowed. For example, I can't say

  foo	bla@halo.net

  in the above example.
• Its not necessary to add rules that point to the default. For example:

  foo	halo@jurai.net

  isn't needed, since the mail will go there anyway.

ERR-CINVAL
An invalid character was detected in the configuration line. You may have used an invalid character in a username or hostname. The following characters are not valid characters in hostnames or usernames.

`~!\@#\$%^&*()=\[\]{};'\:"|,\/\\?

ERR-INVAL
The configuration line had an invalid item in it. You may not have specified a valid email address in the form of 'user@host.dom'
ERR-LOOP
The configuration line may be a loop. You may not specify reciepients using email addresses at the virtual domain that the configuration file is for.
ERR-UMAP
The configuration line isn't necessary. You are mapping an address to the default address, which is redundant, and should not be done.