topic SMTP Problem with ASA in Network Security

SMTP Problem with ASA

Abhishek Shah — Mon, 11 Mar 2019 21:28:45 GMT

Hi there,

I have ASA 5505 firewall, with 8.2.3 version and security plus license. I open ports for my mail server and it works fine. The problem is sometimes the mail could not be deliverd, send me failed delivey notification. I checked everything on server side, this thing happing since we deploy ASA onsite. Mail could not be deliverd becuase the client could not connect to domain.

I suspect inspect esmtp is enable by default, may this create some problem.

Can anyone provide me any info regarding inspect esmtp????

Thanks

SMTP Problem with ASA

varrao — Thu, 22 Sep 2011 14:43:38 GMT

Hi Abhishek,

Yes, this could be the cause of the issue, i suggest you disbale esmtp inspection and try again, chcek if it fails now. Inspect esmpt can only check specific commands being pushed to the server, if there is any other command from that set being sent, it drops the e-mail. You can go through this doc, for those commands:

http://www.cisco.com/en/US/customer/docs/security/asa/asa83/command/reference/i2.html#wp1765148

Hope this helps.

Thanks,

Varun

SMTP Problem with ASA

mvsheik123 — Thu, 22 Sep 2011 14:48:16 GMT

Hi Abhishek,

Guess you got the resolution for the issue (disable inspect esmtp). Check the below link for more info.

http://www.zimbra.com/forums/administrators/49322-solved-cisco-asa-8-4-1-esmtp-inspection-causes-deferred-messages.html

hth