ASA regex to filter smtp traffic

gregbeifuss · ‎04-09-2010

I'd like to put a rule in place on our ASA that will drop any incoming SMTP traffic that has a FROM address matching our domain. For example, drop any inbound SMTP traffic that has a from address of *@mycompany.com. However, I'm really unsure how to do this. Are there any articles or an overview that someone can point me to?

I'm interested in doing this as I believe it will help drop spoofed email traffic at the edge, before it even hits our antispam device.

Thanks,

Greg

Collin Clark · ‎04-09-2010

Greg,

Check this link. It prevents your email server from being a relay which I think is what your after.

https://packetpros.com/cisco_kb/ASA_Prevent_MailRelay.html

Hope it helps.

gregbeifuss · ‎04-10-2010

Hi Collin,

I'm looking more to prevent spam messages getting to my users where the message takes the format FROM Greg@company.com TO greg@company.com as we should not be receiving messages like this inbound. Relaying is already disabled on my mailserver.

Greg