[ale] Anyone have experience hosting email for multiple domains?

[Matt Rideout]

Richard Bronosky wrote, On 08/31/2009 02:23 AM:
> On Mon, Aug 31, 2009 at 1:34 AM, Matt Rideout<mrideout at windserve.com> wrote:
>   
>> Postfix and Dovecot are both good choices. In the past, I've setup
>> Postfix and Dovecot using the docs on their sites. Glancing over the
>> CentOS doc, it looks like it'll at least get you moving in the right
>> direction. IMO, there's no need to bother with virtual users until you
>> have a vanilla setup functional, and are comfortable with it. Once you
>> have that going, dig into Virtual Users. A few random pointers:
>>
>> 1. yum is your friend.
>> 2. Don't be tempted to stray towards sendmail unless you have a very
>> good reasons. It's a PITA.
>> 3. Make sure that sendmail is fully shutdown, and disabled before you
>> try to get Postfix working.
>> 4. Test to make sure you don't have an open relay going each time you
>> make a configuration change.
>> 5. Make sure that you have reverse DNS properly setup for your mail
>> server's IP.
>> 6. Make sure that your mail server's IP isn't on any major blacklists
>> before going live.
>>
>>     
>
> Lot's of good stuff here, thanks. Unfortunately I have to have to
> virtual domains/users working and working right. It is replacing an
> existing setup that I have set up in cpanel with another hosting
> company. I have to get it set up right and fast.
>
> How do I do #4?
> I have concerns about #5 too. Since I will have 8 domains, and cand
> have only 1 PTR record... I have to figure that out.
>
>   
To test for an open relay, you could try setting up a mail client that 
doesn't authenticate (assuming POP before SMTP doesn't let you in), or 
Google for some of the sites out there that will test it for you. What's 
more fun is to use telnet. Try this SSHed into your server, connecting 
to localhost the first time so that you'll see how it works:


telnet 127.0.0.1 25

HELO

MAIL FROM:me at myaddress.com

RCPT TO:me at myaddress.com

DATA

This is a test.
.

quit



For reverse DNS, just run the host command from any *nix box on both 
your IP, and the reverse DNS entry that comes back, if any. They should 
point to each other.