Dropping packets when using smtp

[bennyPeoples]

hi,

i have a 1941 router configured with a zone based firewall. All working fine except the smtp.

we can reseive mails trough pop3 and imap but cannot send trough smtp. I get the following drop to see.

"dropping tcp session x.x.x.x:63025 x.x.x.x du to RST inside current window with ip indent 0"

i have no idea why this is happening. Hope somebody is??

config attached.

Thank you!!

[Flavio Miranda · Accepted solution]

Hello @bennyPeoples

Try to enable packet inspection for SMTP:

ip inspect name inspection-name protocol

https://www.cisco.com/c/en/us/td/docs/routers/access/1800/1801/software/configuration/guide/scg/firewall.html#16883

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[bennyPeoples]

this is what i get on logs.

*Nov  6 20:15:21.178: %APPFW-6-NBAR_PORT_HOP: smtp using 587 port -  tcp session 192.168.1.117:63759 212.71.0.16:587 on zone-pair LAN-WAN class Others
R1(config-if)#
*Nov  6 20:15:35.210: %FW-6-DROP_PKT: Dropping tcp session 195.81.195.51:443 192.168.1.103:57796  due to  policy match failure with ip ident 0

Could it be because the hoster smtp.edpnet.be is blacklisted? Because when i did this with my home account it works fine.

[Flavio Miranda]

Probably. At least, you need to fix this anyway.

-If I helped you somehow, please, rate it as useful.-