Protect R6 smtp against mail forging

HCL Domino Domino Forum
1

Config :R6.0.1, anti-relay parameters set and working;

Global Domain doc :

primary internet domain : a.com

secondary internet domains : b.com; c.com

I’ve configured my R6 config document to block incoming mail to domains a.com; b.com and c.com

when I telnet to port 25, and try to send an email coming from someone@a.com, then it is blocked (as expected)

But when I do the same from someone@b.com or someone@c.com, then these emails are not being rejected…

Basically, I want to protect my SMTP server against remote people who connect to my server, and send an email from a “local_user@local_domain” to “other_local_user@local_domain”.

I can prevent this by blocking incoming mails FROM my local domains, but it doesn’t seem to work well…

What is wrong here ?

Known bug in 6.0.1 ?

2

Subject: Works fine here…

… on 6.0. Just thinking about an upgrade to 6.0.1.

Basically, I have my primary internet domain and all my secondary domains listed in “Deny messages from the following internet addresses/domains:”, delimited with ;

I have quite a few other domains in there too and Domino is correctly blocking them all.

Did you update the SMTP config after making any changes?

tell smtp update

OR

tell smtp quit

load smtp

will do that for you, otherwise older settings can hang around for quite some time before newer ones take effect.

3

Subject: What’re you running into with the block?

“I can prevent this by blocking incoming mails FROM my local domains, but it doesn’t seem to work well…”

Are you running multiple SMTP connections from remote workstations or other servers?

Like Christopher, we have the server set up to block incoming mails from our local domain, and it appears to handle inbound emails quite well. “@local_domain_1; .local_domain_1; @local_domain_2; .local_domain_2”.