[Mailman-Users] Mailman posting question

[Dragon]

Bill Honneus (honneus) wrote:
>Hi,
>
>I have a Mailman setup integrated with Sendmail on the same server.
>When my list sends out posting updates via the bounces address, i.e.
>mylist-bounces at mydomain.com, one of the recipients is an internal user
>defined on the same local server.  So my question is, when the
>mylist-bounces sends out the updates, do the messages destined for local
>addresses go directly to the local address without hitting the outside
>or does mailman send all the messages out to the Internet, and then
>those messages get routed back to the local machine?  This is assuming
>that no special routing is set up with Sendmail MTA.
>
---------------- End original message. ---------------------

MTAs are designed to deliver mail to the correct host based on the MX 
record for a given domain.

So if the MX record for your own domain points to the machine with 
the MTA Mailman is using, it will deliver it locally on the same 
server. There is no reason for it to ever be placed on the wire 
because it has nowhere else to go. In order for it to work as you 
suggest, another SMTP server would have to serve as an open relay to 
send it back and that is not such a good idea. It's bad because it 
wastes bandwidth and because it leaves a big hole open for abuse.

Dragon

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