[Mimedefang] Interaction between filter_relay and sendmail MAIL FROM: name resolution

Nels Lindquist nlindq at maei.ca
Wed Sep 18 18:26:01 EDT 2002


On 18 Sep 2002 at 17:25, Rajesh Bhandari wrote:

> We have some machines that need to relay mail through our mailhub.  The
> mailhub is running MD2.21 and Sendmail 8.12.5.  The key point is that
> these machines are not in DNS.  Their IP address range IS on a local
> subnet.
> 
> I was going to set them up to relay using the filter_relay function. 
> How does this interact with the sendmail MAIL FROM behavior, where it
> does a reverse lookup on the IP and does not allow the connection if it
> cannot be resolved.  Needless to day, I am reluctant to use
> FEATURE('accept_unresolvable_domains').
> 
> So, would returning a 0 for filter_relay allow these machines to
> relay?

You shouldn't need to involve MIMEDefang at all for this, nor should 
you require FEATURE(`accept_unresolvable_domains').

As long as FEATURE(`access_db') is present, you should be able to do 
everything there.

You'll need an entry in /etc/mail/access of the form:

Connect:192.168.1.1         RELAY
Connect:192.168.1           RELAY

The first line will allow relaying from just one IP address, the 
second will allow relaying from an entire subnet.

Then rebuild your access.db map file.  You shouldn't even need to 
restart sendmail.

----
Nels Lindquist <*>
Information Systems Manager
Morningstar Air Express Inc.




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