postfix help and off the blacklist

[Fraser Campbell]

Madison Kelly wrote:

>   I've finally made the switch from Sendmail after many people here 
> suggested I do so. Of course now I am having trouble getting virtual 
> hosting working. I'm confused about what I should be using as the 
> 'myhostname' and such.

You can put almost anything in there but in general I would make sure 
that all of the names generally used match up.

Let's say you use the name mail.alteeve.com and IP 1.2.3.4:

- 4.3.2.1.in-addr.arpa. should point to mail.alteeve.com on the Internet
- mail.alteeve.com should point to 1.2.3.4 on the Internet
- all domains that use mail.alteeve.com should have mail.alteeve.com as
   primary MX (definitely not CNAMEs and IMO not even alternate A
   records)

None of these recommendations are hard and fast requirements but they 
make things match up nicely and some of these recommendations are 
relevant to anti-spam systems.

myhostname is the name that your server reports when sending email 
(HELO/EHLO) and receiving (welcome banners).  You could set it to 
gibberish (not nice) and some mail would still work.


>   Any help, even just a pointer to a more concise how-to for someone 
> trying to virtual host multiple domains pointed at system users would be 
> great. The postfix docs keep talking about using LDAP, SQL and such 
> which just keeps throwing me for a loop.

It's fairly simple once you get the hang of it, quick recipe:

- point every domain's primary MX to your server (again I'd go with
   matching name from DNS PTR + myhostname + A record)

- in virtual maps add a fully qualified address (LHS) pointing to a
   local user (RHS), like this:

   madison-8t3yKezk0FFBDgjK7y7TUQ at public.gmane.org  madison

- make sure local user (madison) exists.  "Local user" just means
   someone that can be found in local_recipient_maps (IIRC).
   local_recipient_maps contain passwd file by default, if you wish to
   add LDAP/SQL users that's doable but you have to understand the basics
   first

- IIRC the virtual domains do not have to be listed under mydestinations
   ... they can be but I don't think there's a need

I use mysql to host all my virtual domains, I wrote a simple web 
interface to let users manage their own domains, you might want to look 
into that eventually there's a good howto out on the net somewhere 
(postfix + mysql + virtual).   I'm hoping to check out Zimbra eventually 
(which still uses postfix actually).

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