The issue happens when InterScan Messaging Security Suite (IMSS) receives EHLO command from xxx.com. It is in the form of "XXXX xxx.xxx.com". Xxx.xxx.com will send the HELO command, but after IMSS acknowledges it, the remote server cancels the connection.
The XXXX indicates that there is something in front of IMSS that masks the EHLO command. There could be a PIX firewall configured in front of IMSS. You can set up Cisco Pix firewall to disable the fixup protocol SMTP.
For further details on how to disable the feature, consult your Cisco PIX firewall representative.
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