Exchange/Sendmail Configuration Problem

[David Karakas]

I want to set up a HP box to route all outbound mail to an exchange server that has access to the public internet. I also want to set up the exchange server to receive the HP boxes mail (via DNS MX) and route it to the HP box. The goal here is to allow bi-directional e-mail to/from the public internet that goes through the exchange server.

Currently, I have myhpbox.foo.bar.com relaying mail to myexchange.foo.bar.com and this works quite well. This was accomplished using the DS macro in the sendmail.cf file.

I have a public DNS server with the following:

12.59.1.96 IN A myhpbox.foo.bar.com
MX 10 myexchange.foo.bar.com

12.59.2.120 IN A myexchange.foo.bar.com

Problem:

When mail is sent to user@myhpbox.foo.bar.com the originating mail server does a nslookup and discovers the MX record and correctly forwards the mail to myexchange.foo.bar.com. Now myexchange.foo.bar.com having received the mail performs its own nslookup for myhpbox.foo.bar.com, discovers the MX record and forwards the mail to itself in a loop until ttl kills it. Exchange doesn't seem to know what its hostname is.

I believe that the HP sendmail is configured correctly. What do I have to do to get exchange to do what we intend?

On exchange we have tried putting in the ip address to forward to but it reconstructs the To: header and changes it to user@ipnumber instead of user@fqdn. This causes sendmail to reject it.

Please only answer this if you have successfully performed the same type of environment. I have already received many well intentioned but wrong suggestions.

Thanks
David
kard235@lni.wa.gov

[CHRIS_ANORUO]

Have a look at this link: http://forums.itrc.hp.com/cm/QuestionAnswer/1,1150,0x515868c57f64d4118fee0090279cd0f9,00.html

[Mike McKinlay]

Your problem is that you're using the same DNS server to resolve the same MX record for the HP system.

What I would do is put the generic foo.bar.com MX record on the public DNS so all mail is routed to the Exchange server. Then use an internal DNS server to create the MX record for the hp.foo.bar.com system.

Have Exchange look to the public DNS to lookup only Internet addresses. Give Exchange the second DNS server for internal resolution.