We had a problem with SMTP inspection dropping some regular emails (Cisco 2901 IOS 15.0).
The original configuration, made using CCP, was:
access-list 102 remark CCP_ACL Category=0
access-list 102 permit ip any host 192.168.1.111
class-map type inspect match-all sdm-nat-smtp-1
match access-group 102
match protocol smtp
policy-map type inspect sdm-pol-NATOutsideToInside-1
class type inspect sdm-nat-smtp-1
inspect
....
zone-pair security sdm-zp-NATOutsideToInside-1 source out-zone destination in-zone
service-policy type inspect sdm-pol-NATOutsideToInside-1
Here is how to avoid this inspection:
no access-list 102
access-list 102 remark CCP_ACL Category=0
access-list 102 permit tcp any host 192.168.1.111 eq 25
class-map type inspect match-all sdm-nat-smtp-1
no match protocol smtp
match protocol tcp
Incoming mails are going thru Spam and Virus Blocker so that bypassing SMTP inspection is not security issue in this case.
Hope this will help somebody.
