Error 421 Smtp connection went away

[avburren1]

Hello,

I 've got some problem with my Mail Server since I've migrated to an ASA5510.
Actually the server is in a DMZ with a private Ip ( 10.x.x.2) and it is translated to a Public IP ( 194.x.x.65).
I use these configuration :

static (DMZ,LAN) 194.x.x.65 10.x.x.2 netmask 255.255.255.255
static (DMZ,LAN) 194.x.x.66 10.x.x.3 netmask 255.255.255.255
static (DMZ,WAN) 194.x.x.65 10.x.x.2 netmask 255.255.255.255
static (DMZ,WAN) 194.x.x.66 10.x.x.3 netmask 255.255.255.255
static (LAN,DMZ) 192.168.0.0 192.168.0.0 netmask 255.255.248.0

Some Users received in there mailbox a system administor error message :

Object : Impossible to deliver : test
Your message could not be deliver to one or more of its recipients: 421 SMTP connection went away!

When they try to re sent it some times later, message is sent whithout problem.

Any Ideas about it ?

[avburren1]

no one?

[Latchum Naidu]

Hi,

There must be some other problem with your SMTP server not from network end.

See the below discussion for the smae.
http://objectmix.com/pine/206253-problems-connecting-smtp-server.html

Please rate the helpful posts.
Regards,
Naidu.

[avburren1]

Ok, and what about the "ESMTP inspection". Can it be the problem?

[Latchum Naidu · Accepted solution]

Hi,

Ok, if you have ESMTP enable then there are chances to most of your SMTP mails bounce due to ESMTP inspection.

You can disable only the default ESMTP in default service policy with below command in config mode.

#no inspect esmtp

Please rate the helpful posts.
Regards,
Naidu.