sendmail configuration

[netwelder]

We have an IBM Risc box running AIX. It has sendmail installed. I switched our ISP. My email is now not working. Do I need to change settings in sendmail to get it working again? Thanks in advance for any help.

 

[n0cmonkey]

Incoming or outgoing? Anything in the logs?

Did you change the MX entry in DNS to the new IP?

 

[netwelder]

We have .forwards setup to forward our email to our home accounts. We don't have a true email server. I don't know much about AIX. I am pretty familiar with networking in general. What do I need to change? I can login as root and get a #, but I really don't know any commands. Thanks.

 

[n0cmonkey]

Originally posted by: netwelder
We have .forwards setup to forward our email to our home accounts. We don't have a true email server. I don't know much about AIX. I am pretty familiar with networking in general. What do I need to change? I can login as root and get a #, but I really don't know any commands. Thanks.

What you need to change depends on what is wrong.

Email comes into your AIX machine addressed to (as an example 😉) netwelder@company.com. You have setup a .forward to send it to netwelder@yourhouse.com. Right?

You're having trouble receiving mail, correct?

Did you change the DNS entry for the mailserver? It was probably pointing to the IP address given to you by the last ISP. You'll need to have it changed to the IP address the mailserver is using given to you by the new ISP.

Is there anything relating to failures in the sendmail logs?

 

[netwelder]

Yes the forwarding you describe is accurate. I haven't changed anything on the server. So, I need to change the IP address the mailserver is using? How do I check the sendmail logs? I don't know if the new router is blocking incoming mail or if it is in fact getting to the server. I setup a new Linksys VPN router with a firewall. Could that be the problem?

 

[n0cmonkey]

Originally posted by: netwelder
Yes the forwarding you describe is accurate. I haven't changed anything on the server. So, I need to change the IP address the mailserver is using?

I don't know. Where's the network admin? Where's the unix admin? The old ISP provided you one or more IP addresses. When you changed ISPs, the IP address(es) you are supposed to use changed. Whether you have a NAT device on the perimeter or not would clue you in on whether the IP address of the AIX machine needs to be changed.

If you are using a NAT device, the IP address is probably fine (although you may have to setup port forwarding, if you got a new NAT device). If you aren't the IP address probably needs to be changed (and I don't know how to do it on AIX).

As far as the DNS entries go, you'll have something like mail.company.com pointing to your AIX server's IP address. It'll be identified as an MX record. The IP address in the MX record probably belongs to your old ISP, and would have to be changed to the new IP. Whoever does your DNS can help you with this.

How do I check the sendmail logs?

I'm not sure where they are on AIX, but they should probably be in /var/log. cd /var/log should move you to that directory. You can use the command more filename to inspect the files. If none of the files identify themselves as sendmail or mail related, take a look at the messages file.

I don't know if the new router is blocking incoming mail or if it is in fact getting to the server. I setup a new Linksys VPN router with a firewall. Could that be the problem?

That could be the problem. Make sure it is forwarding TCP port 25 to the AIX server. You should be able to find out the IP address of the AIX machine with the command ifconfig -a

 

[skyking]

I concur, the router will stop mail completely if not configured. The IP address change and incorrect DNS records will also do that.