We recently decided to use a dedicated spam server to filter our incoming email. We're using one at our main office in Europe and it works very well.
Our incoming mail is routed to an address on our router which then redirects it to our email server. That server was addressed xxx.xxx.xxx.2. Another address on that router directs to our webmail on the same server (2nd NIC) at xxx.xxx.xxx.8. Everything works just dandy.
The plan is to put the spam server at xxx.xxx.xxx.2, the address pointed to as the email server. And then redirect scanned email to port 25 on the email server at xxx.xxx.xxx.4. Works great. No problem with incoming email.
However, there are problems with outgoing. Some smtp mail simply sits in the queue until it eventually fails to be delivered. For example, I can send smtp from my office Outlook account to my yahoo or hotmail accounts with no problem. However, when I send to my AOL account it never leaves the queue. I know...some of you will laugh and say big deal. Well, it is. We have quite a few users in remote locations that use AOL. Plus we have a several dozen customers who also use AOL for email.
If AOL does a reverse lookup as part of it's spam or malicious mail check, then I'm thinking perhaps a PTR entry is required somewhere. But where? Or maybe that's not it at all.
At this point every address I've checked seems to work fine but AOL. There are probably others but I haven't yet discovered them.
And here's the kicker. If I shut down the spam server and readdress the mail server back to the .2 original address and do all the necessary internal DNS registration, all the AOL mail leaves the queue. Yes, I've tried other addresses than .4. Doesn't matter. Only .2 will send to AOL.
Anyone have any thoughts or ideas?
Thanks,
Bob (not so Zoom today)
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