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Im running an Ubuntu 8 with exim4 as the MTA. I can receive email but cannot send using has already setup the reverse dns 48 hours ago but to no effect. the logs says its listening to port 25. Help!


Ive now disable exim4 and replaced it with postfix. and its the same story but the error now says cannot access ports instead of timing out. yes i can telnet and ehlo thing.

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What error does exim report when trying to send mail? – Jon Lasser Dec 14 '09 at 21:59
Your ISP is blocking that port, you are sending to the wrong host, or it has only port 773 (submit) open. Many ISPs block mail servers other than their own. Their server should relay for you; you can configure exim to use that relay. Confirm that you're connecting to the right host: dig mx <fqdn-of-mail-host> This should report back the correct mail exchangers, which you should be able to telnet to on port 25. If it's your ISP's official server, try telnetting to the Submit port. If that works, configure exim appropriately. – Jon Lasser Dec 15 '09 at 15:51

None of what's been stated so far has anything to do with SENDING email from your server. PTR records are not a requirement for sending email. The fact that your server is listening on port 25 means that it can recieve connections on port 25 (for recieveing email) but doesn't have any bearing on it's ability to send email. Does your email server have logging functionality? If so, what type of logging? Have you enabled logging? Have you looked at the logs? Can you make an outbound telnet connection from your server to another email server on port 25?

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Just for the record, some receiving email servers require a PTR record for the sending MTA to be setup before they will talk to a sender. is one that I am aware of. – Scott Lundberg Dec 14 '09 at 15:28
Yes some do, but many don't, and a PTR record is not a requirement. The problem sounds to me like a general failure to send any outgoing email and not a problem with specific domains, that's why I'm not going down the PTR record road. The OP needs to provide for specifics as to the problem so we have a better idea of exactly what's happening or not happening. – joeqwerty Dec 14 '09 at 16:07

What about the forward DNS? Reverse or PTR record is there to help send mail between servers. Can you ping and get back the appropriate IP response? If the answer is yes can you telnet to that IP address on port 25?

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yes, i can ping my mail domain. i cannot telnet (used 'telnet ip-address 25').. stuck on 'trying ip-address. – Ericzoo Dec 15 '09 at 13:27
sounds like it's not allowing connections – Dave Holland Dec 15 '09 at 14:19

Can you telnet out to port 25?

Some ISPs block outbound port 25 except to their own servers; AT&T is one that does this.

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This seems most likely – artifex Dec 15 '09 at 12:30

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