topic Re: Question about MTA and bounced messages in Firewall and Security Management

Question about MTA and bounced messages

Dilian_Chernev — Fri, 01 Apr 2022 07:05:22 GMT

Hello,

We have some issues with bounced messages that CP MTA postfix is trying to send directly with MX resolving.
In some cases the MS Exchange server reject some messages and CP MTA postfix is trying to send "non-delivery notification" to original sender, which is perfectly normal.
Delivery to original sender is done by MX resolving of senders address which is also normal.
For security reasons we don't want CP MTA to send directly these "non-delivery notifications" to original sender, but to send them to Security Mail Gateway which is responsible for outgoing mail delivery.

Here is simple picture what we are trying to achieve:

Is it possible to use smarthost functionality of postfix - "relayhost=" setting to achieve this?
Or is there any better solution for this.

Thanks,

Dilian

Re: Question about MTA and bounced messages

PhoneBoy — Fri, 01 Apr 2022 13:57:06 GMT

That's kind of the point of configuring smarthost, if I recall: forward all external email to a specific SMTP server.

Re: Question about MTA and bounced messages

RS_Daniel — Fri, 01 Apr 2022 17:08:44 GMT

Hi,

If i understand correctly a similar question was answered here:

https://community.checkpoint.com/t5/Threat-Prevention/MTA-and-Non-Delivery-Report/m-p/24171

Take a look to the comment starting with "One more question:".

If it is not your case sorry XD. HTH.

Regards

Re: Question about MTA and bounced messages

Dilian_Chernev — Sun, 03 Apr 2022 18:51:04 GMT

Thank you @RS_Daniel 🙂

Seems exactly like my case!