Only accept mails from incoming SMTP gateway
Problem reported by Sébastien Riccio - 5/13/2019 at 8:42 AM

We are using incoming gateways for spam handling and then forwarding mails to our main SmarterMail server. 
We process SPAM on these incoming gateways and add headers depending the result, so we can score the mails based on custom filters that check these headers. It works like a charm.

The problem is how can we tell SmarterMail to only ACCEPT mails coming from the incoming gateways and not allow mails directly delivered from outside to it's SMTP port.

I know how to do it with exim, postfix even sendmail, but I can't find that option in SM16.

Even google offers this setting in their GApps mail service (found it while google for answers with smartermail):

Thanks a lot for your help
Sébastien Riccio
System & Network Admin

3 Replies

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Kyle Kerst Replied
Employee Post Marked As Resolution
You can whitelist the gateway address, then blacklist a range including public IP addresses above and below that address. Whitelist entries are considered prior to blacklist entries, so this should restrict incoming SMTP to your gateway servers. 
Kyle Kerst
System/Network Administrator
SmarterTools Inc.
(877) 357-6278
Sébastien Riccio Replied
Hello Kyle and thank you for your answer. 

We will try this and see how it goes :)

Sébastien Riccio
System & Network Admin

Manuel Righi Replied
Hello Kyle, you mean blacklist and whitelist io of incoming gateway servers ?


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