Hello, I am having issues with our Exchange 2007 server sending emails to AOL. The emails send, but they are never delivered to AOL, we eventually get timeout errors. I am working with AOL to figure out the issue, and they want me to do a manual telnet from our Exchange 2007 server. My problem is, when I type in "telnet mailin-01.mx.aol.com 25" from a command prompt, I get a successful connection, but anything I type in after that will not work. The command I'm trying to type in is: HELO mydomain.com or EHLO mydomain.com Every command I type in, it returns 500 SYNTAX ERROR, COMMAND UNRECOGNIZED Below is a copy/paste of the screen: 220-**************************************************************************** *** 220-******************************************************** 220-**************************************************************** 220-***************************************************************** 220-***************************************************************** 220-************************************************************** 220 *********************************************** HELO mydomain.com 500 SYNTAX ERROR, COMMAND UNRECOGNIZED I have verified the telnet service is started, I'm not sure what I'm doing wrong. Does anyone have any ideas? Thanks!!

Are you backspacing at all? That can break the syntax.From my Exchange server I type: telneto mail.something.net 25EHLO somethingTry telnet to another mail server you know of.

Hi, I'm not backspacing at all, I tried to telnet to hotmail.com (mx1.hotmail.com 25) and I got something similar. After the successful connection, I type in EHLO mydomail.com and it says 500 unrecognized command ??

Do you have PIX Firewall in your environment? Check & follow below KB article... http://support.microsoft.com/?id=295725 Additionally check below links... http://exchangedeepthoughts.blogspot.com/2007/10/esmtp-and-pix-firewalls.html

We don't have a PIX firewall, but we do have a Cisco ASA5510. I can telnet successfully from any PC, it just won't allow it from any server. I would think if it's a firewall issue, I wouldn't be able to do it from anywhere.

Seems as though you are successfully connecting via telnet, but I'm not sure why your EHLO/HELO commands are failing.I was able to get a response from mx1.hotmail.com from my own Exchange server.For EHLO/HELO you can send pretty much any text you want. For example you could just say: EHLO sup

Dear customer: When I telnet mailin-01.mx.aol.com 25 from my machine, it return the following information: 220-rly-da03.mx.aol.com ESMTP mail_relay_in-da03.5; Wed, 24 Dec 2008 22:08:19 -0 500 220-America Online (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. Effective immediately: AOL 220- may no longer accept connections from IP addresses which 220 have no reverse-DNS (PTR record) assigned. While your return looks abnormal. Please double check whether you enable Mailguard feature on your Cisco firewall according to the following article: Cannot send or receive e-mail messages behind a Cisco PIX firewall http://support.microsoft.com/kb/295725/en-us Hope it helps.Rock Wang MSFT