Sending mail from a home server

[Jonathan Hutchins]

There are a number of issues in trying to send mail for various accounts 
through a home SMTP server.

First, if you read the doccumentation on "virtual domains" for your 
mailserver, it will tell you how to allow outbound mail to appear to come 
from some other address than mailserver.homenetwork.net or whatever.  This is 
pretty common, most mailservers have hostnames other than the unqualified 
domain name that mail appears to be from (homenetwork.net in this case).

Next, you need to deal with the fact that a lot of mail servers are configured 
to reject connections from servers at IP addresses that are listed as part of 
the IP pool of an ISP.  This is a very crude method of spam blocking, but 
more and more administrators include it by default in their configurations.

To get around this, you'll have to relay mail for those hosts through your 
ISP's mailserver.  This may be possible on a per-domain basis, your mailer 
may allow you to fall back to this route if delivery fails, or you may end up 
routing everything through the ISP's server.

Most ISP's are pretty good about this, but some will object to sending mail 
that appears to come from somenetwork.com through their ispnetwork.com host.  
This would allow people to relay mail from illegitimate networks through 
thier valid network and open them to spam relays if they weren't careful.  If 
you have the bad luck to end up in this situation, and can only send mail 
that originates from ispnetwork.com, look for another ISP.

My general advice is try it, and if it doesn't work find a way around it.