Dovecot Mailserver sending, but not receiving
 

Dear LQ members,

I've read some posts with similar problems, but it's not quite this problem.

I have followed the guide for "The Perfect Server - Debian Lenny (Debian 5.0) With BIND & Dovecot [ISPConfig 3]" and all is well, except.

I can send mail (to GMail) from commandline.
I can send mail (to GMail) from any of the domains configured in ISPConfig3 through SquirrelMail (how ever terrible that looks, but functions) or IMAP/POP.

but....

I can't receive mail (from GMail) on any of the domains configured in ISPConfig3 in SquirrelMail or IMAP/POP.

I have my domains configured with proper MX records (just like I have them configured at work).
I have all ports (80, 143, 110, 25, 22, etc) forwarded on my router that are needed.

I can Telnet to localhost and all checks are fine.
I can send and receive from and to local domains on the same server, which makes sense.

but

I can't Telnet from any external server to my server behind NAT.


Conclusion:

I figured it MUST be a network/port-forwarding problem as the external Telnet requests fails to my machine on port 25.

Tested my router if it would let met communicate through port 25 and it would.

So it must be my ISP, as I read in different posts.


Question:

Maybe I'm a n00b, but in all other posts the problems were with receiving AND sending.

My ISP responded that port 25 is blocked because of spam issues.

But I can mail (and even spam if I would like to) to external domains while I didn't do anything weird to make that happen.

The only thing I wish for is to receive mails and if you'd ask me, port 25 would be solely for outgoing mails, not for incoming mail deliveries throught MX?

Or am I terribly wrong?

An ISP surely wouldn't disable their customers in having a mail-server for incoming mails, as long as they would send out through their own smtp server to make sure they wouldn't spam the world?

I hope someone can explain this to me, thanks in advance.


Richard

Unfortunately, it looks like you have everything working correctly but are facing port 25 being blocked by your ISP. The first thing I try is contacting your ISP and see if you can get this block lifted. Many ISPs do block port 25 on 'residential' accounts in an effort to cut down on the amount of SPAM transmitted. You may be able to persuade them you have taken the steps necessary to run a responsible mail server. You will likely want to contact them in writing and get the contact information of a responsible party first. Simply calling into to the standard customer-no-service rep will probably be futile.

A second route would be to use what is called a mail reflector. These services seem to run about $30/$40 year USD. Here is a link to a discussion on this subject. As the discussion points out, if you try to run on a different port, other servers won't know how to find yours.