I have seen this many times, it often is sporadic...and often it is because the sending system is using Exchange. Can't find the exact doc right now, Cisco says turn it off. Here are some examples though.
http://www.cisco.com/c/en/us/support/docs/security/asa-5500-x-series-next-generation-firewalls/113423-asa-esmtp-smtp-inspection.html http://networkengineering.stackexchange.com/questions/6075/to-inspect-esmtp-on-asa-or-not From: [email protected] [mailto:[email protected]] On Behalf Of David McSpadden Sent: Monday, December 21, 2015 10:48 AM To: [email protected] Subject: [Exchange] RE: Ironport ESA showing recieving aborted Just for one domain though? I looked through the Asa logs and this one domain and sendgrid.??? Is all that is being caught in this ESMTP inspection?? From: [email protected]<mailto:[email protected]> [mailto:[email protected]] On Behalf Of Kennedy, Jim Sent: Monday, December 21, 2015 10:42 AM To: '[email protected]' <[email protected]<mailto:[email protected]>> Subject: [Exchange] RE: Ironport ESA showing recieving aborted Check for SMTP fixup/inspection on the ASA, it needs to be off. From: [email protected]<mailto:[email protected]> [mailto:[email protected]] On Behalf Of David McSpadden Sent: Monday, December 21, 2015 10:39 AM To: [email protected]<mailto:[email protected]> Subject: [Exchange] Ironport ESA showing recieving aborted I think this is an issue on the ASA firewall dropping ESTMP because of SMTP inspection. Is there any way this could be at the Exchange 2010 level? ASA firewall allows port 25 to ESA device that is the SMTP connector to Exchange 2010? David McSpadden System Administrator Indiana Members Credit Union P: 317.554.8190 [Description: Description: imcu email icon]<http://imcu.com/> [Description: Description: facebook email icon] <https://www.facebook.com/IndianaMembersCU> [Description: Description: twitter email icon] <https://twitter.com/IndMembersCU> [Description: Description: email logo] [http://www.amuletsolutions.com/images/mcp.gif]<http://www.google.com/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0ahUKEwjFztf-tePJAhXK5iYKHcPtAxEQjRwIBw&url=http://www.amuletsolutions.com/awards.aspx&bvm=bv.110151844,d.amc&psig=AFQjCNHkrx8CednTEOOq4zUxYyrRUGzUsg&ust=1450459757284499> This e-mail and any files transmitted with it are property of Indiana Members Credit Union, are confidential, and are intended solely for the use of the individual or entity to whom this e-mail is addressed. If you are not one of the named recipient(s) or otherwise have reason to believe that you have received this message in error, please notify the sender and delete this message immediately from your computer. Any other use, retention, dissemination, forwarding, printing, or copying of this email is strictly prohibited. Please consider the environment before printing this email. This e-mail and any files transmitted with it are property of Indiana Members Credit Union, are confidential, and are intended solely for the use of the individual or entity to whom this e-mail is addressed. If you are not one of the named recipient(s) or otherwise have reason to believe that you have received this message in error, please notify the sender and delete this message immediately from your computer. Any other use, retention, dissemination, forwarding, printing, or copying of this email is strictly prohibited. Please consider the environment before printing this email.
