[CentOS] Force sendmail outbound routing for specific domain name

Thu Apr 10 02:54:28 UTC 2008
Hugh E Cruickshank <hugh at forsoft.com>

CentOS 4.6

Hi All:

Is it possible to force sendmail to use a specified host name for
outbound email to a selected domain name instead of the host name
that can be found by looking up the DNS entry?

The problem is that we have a client that uses the same ISP as we
do and the IP addresses assigned to both of us are very close. This
has resulted in connection problems specifically with our outbound
email to the client. I believe it is an issue with TCP/IP routing.
In the past the ISP has setup some sort of special routing that 
redirects our email to the ISP's backup mail server which then
delivers the mail to the client. Every once in a while the ISP does
something with their configuration and the routing override is lost
for several days until we can get them to recognize the problem
and then figure out what they did the last time. This happened
over the weekend and we are still waiting on the ISP to fix it up.

My thought was can we configure this in our mail server so that we
and our client do not have to suffer with this again?


Regards, Hugh

Hugh E Cruickshank, Forward Software, www.forward-software.com