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All e-mail sent from a server to my domain fails to be correctly received. The difference between and other domains is that they open with HELO rather than EHLO and therefore attempt to send the data in one part rather than in chunks (as I understand it).

Looking at the wikipedia example communication it seems that we are conforming to the protocol our side. When we expect data to arrive with us however the yahoo server fails to reply leading to a timeout.

2010-10-27T09:17:18.11...*,SMTPSubmit SMTPAcceptAnySender SMTPAcceptAuthoritativeDomainSender AcceptRoutingHeaders,Set Session Permissions
2010-10-27T09:17:18.11...>,"220 Microsoft ESMTP MAIL Service ready at Wed, 27 Oct 2010 10:17:17 +0100",
2010-10-27T09:17:18.13...>,250 Hello [],
2010-10-27T09:17:18.14...<,MAIL FROM:<>,
2010-10-27T09:17:18.14...*,08CD4019188CB09A;2010-10-27T09:17:18.111Z;1,receiving message
2010-10-27T09:17:18.14...>,250 2.1.0 Sender OK,
2010-10-27T09:17:18.16...<,RCPT TO:<>,
2010-10-27T09:17:18.16...>,250 2.1.5 Recipient OK,
2010-10-27T09:17:18.17...,>,354 Start mail input; end with <CRLF>.<CRLF>,

I am stumped as to what to try, I attempted to manually telnet and send an e-mail but I get rejected as I don't have a valid server to send from (I get refused as potential junk).

I have access to the logs of the box but not easy access to the config. Any advice would be greatly appreciated.

share|improve this question
Can you do capture the network traffic on your email server? If so, send an email from yahoo and another one from a different domain. Then, you can compare the two dumps. This may give you a hint. – Khaled Oct 31 '10 at 11:27
What kind of firewall are you using? Some have protocol awareness and restrict the commands/traffic format that they will allow through (PIX "fixup" for example). – Hutch Oct 31 '10 at 12:20
I'm pretty sure in the SMTP connector there is an option to take both EHLO and HELO, – SpacemanSpiff Oct 31 '10 at 14:24

It shouldn't have anything to do with the remote server sending HELO instead of EHLO, as Exchange server supports both. You can see in your log file entry that eveything is going smoothly until your Exchange server issues a 354 response, which means "give me the message", and then it dies. Is there more in the log after the last line that you've posted?

share|improve this answer
Unfortunately not, the next log message is from 19:08 and precedes a new successful message. – gav Nov 1 '10 at 11:33
In that case then Khaled's suggestion would be the thing to do. – joeqwerty Nov 1 '10 at 12:24

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