Postfix selectively blocking countries?
I am trying to configure a mail server on Debian Squeeze using Postfix and Dovecot. Dovecot seems to be working fine, I can log in to gmail and send emails to my Linode running Dovecot, then configure my mail client at home for the Linode and retrieve the emails.
The problem I am having is with Postfix. It seems to have loaded just fine, but I cannot configure my mail client for SMTP, nor will Gmail connect via SMTP, though Gmail works fine with the Dovecot server.
When I ssh to the Linode and telnet into the mail server, I can send myself an email, but telnet'ing to the mail server from home doesn't work. I asked someone for help on an IRC channel, and he was able to telnet in to port 25 and send me a message (he does NOT have ssh access), and he lives in Switzerland. This leads me to believe that either Linode or Postfix is blocking the USA (the country I live in) on port 25 because I seriously doubt I use the same ISP as Gmail.
6 Replies
Also, I'm not sure how you're sending mail to Dovecot, as it does not handle mail transport: it just handles IMAP and POP3. Postfix (which just handles SMTP) would be what you're talking to.
What's the right-hand side (i.e. the domain) of the e-mail address you're trying to work with? Does anything show up in Postfix's log when you try to send to it from Gmail?
The Linode domain I'm trying to use is youdolinux.com, and the MX record reads mail.youdolinux.com. The MX record is what I'm pointing my client to, but I don't include the mail part when sending myself mail from Gmail (e.g. I type
Comparing the Postfix main.cf on my Linode to the Postfix main.cf on the machine running on the other host, the only difference (other than pointing to a different domain) is that I'm not using procmail. Since I'm not familiar with email servers, I can try configuring this, but since procmail wasn't pulled in by apt-get when I installed dovecot-imapd and postfix, I was assuming this isn't necessary.
As hoopycat suggested, I would check the mail logs for Postfix to see if there are any connections attempted from Google/Gmail at all, in case something on your system (such as spam prevention) is dropping connections of e-mail from their servers.
I would also check Gmail's troubleshooting guides on the subject for more information:
Messages I send aren't arriving at their destination
My domain can't receive mail from Gmail
And another thing: I noticed that the reverse DNS for you IP address still points to your Linode default (li283-45.members.linode.com). Without being sure, that might also be a contributing factor.
$ nc mail.youdolinux.com 25
220 www.youdolinux.com ESMTP Postfix (Debian/GNU)
HELO witte.lan.hoopycat.com
250 www.youdolinux.com
MAIL from: <rtucker@hoopycat.com>250 2.1.0 Ok
RCPT to: <postmaster@youdolinux.com>250 2.1.5 Ok
QUIT
221 2.0.0 Bye</postmaster@youdolinux.com></rtucker@hoopycat.com>
I completely forgot about the setup I hacked together awhile ago for bypassing the port 25
I managed to get it working, but now I have an authentication error. I'm googling for it without much luck (it seems kinda confusing for a guy who's not familiar with mail servers), so if I can't fix it, I'll start a new thread.
As for setting up reverse DNS, just go to your Linode in the Linode Manager, then go to the "Remote Access" tab and click the "Reverse DNS" link underneath your Linode's public IP. From there, enter the hostnamename (such as "server1.youdolinux.com" or even just "youdolinux.com") you want as the reverse DNS name, as long as that hostname already points to your assigned IP address. Once it's saved, it's only a matter of waiting time until the reverse DNS name appears for everyone (ie. DNS propagation). It's as simple as that.