Post Fix Help

[techntutor]

I am using Fedora Core linux for the operating system and Postfix as my mail server. Users that have email addresses with Comcast or AOL do not get any mail that is sent from my mail server but all other do, like those with Yahoo or personal domains. I have contacted Comcast and they verified that my IP is not blocked. I tried to look at my mail logs and they are blank. Has anyone run into this issue and is there a fix?

[bobkberg]

Before getting into anything PostFix specific, I'd recommend that you try manually sending a test email by Telnet MailServer 25, and go through the basic sequence:
HELO yourdomain.com
MAIL FROM: <youremail@yourdomain.com>
rcpt to:<recipient@theirdomain.com>
data
This is only a test, please don't respond
.
quit


Be careful to NOT use the backspace key - it will not work.
Better to type the test script in an editor window and copy/paste it to the telnet session.

The key idea being to actually SEE what the mail server's response is. If that doesn't work, or if you get a response that doesn't help, then write back.

Good luck,

Bob

[techntutor]

Before I read your replay I went back to Sendmail, Same Issue, Users with Comacast emais and AOL are not receiving the mail I know the server is working beacuse I CC myself and I get the messages. So its not the MTA. Any other suggestions?

[bobkberg]

Did you try it in a manual SMTP session? If so, what was the response from the mail server(s)?

I just tried it with aol.com and got the following:
220-mtain-mj01.r1000.mx.aol.com ESMTP Internet Inbound
220-AOL and its affiliated companies do not
220-authorize the use of its proprietary computers and computer
220-networks to accept, transmit, or distribute unsolicited bulk
220-e-mail sent from the internet.
220-Effective immediately:
220-AOL may no longer accept connections from IP addresses
220 which no do not have reverse-DNS (PTR records) assigned.

Which begs the question: Does your IP address have a reverse DNS lookup which includes your own domain name?

This is why I suggested that you do the test process manually, not using Postfix or Sendmail. Alternately, you could sniff the connection attempt and read the response in the Wireshark/Ethereal capture.

Bob