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Topic: Preventing backscatter

==== REQUIRED BASIC INFO OF YOUR IREDMAIL SERVER ====
- iRedMail version (check /etc/iredmail-release): 0.9.6
- Linux/BSD distribution name and version: CentOS 6.10
- Store mail accounts in which backend (LDAP/MySQL/PGSQL):  LDAP
- Web server (Apache or Nginx): nginx
- Manage mail accounts with iRedAdmin-Pro? YES
- [IMPORTANT] Related original log or error message is required if you're experiencing an issue.
====

I find that spammers love to hit a backup mx when the primary doesn't accept their messages. This is causing problems with backscatter as my backup mx server that accepts and attempts to deliver mail to non-existant users. I guess I could set the final destiny to discard but it would be better if there a method to have it check with the master before accepting and relaying the mail. Any thoughts on this?

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Re: Preventing backscatter

*) How about implement relay_recipient_maps on backup mx server? You can replicate LDAP data to backup mx, it should be very easy.
*) FYI: http://www.postfix.org/BACKSCATTER_README.html

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Re: Preventing backscatter

Is it possible to read the remote LDAP database rather than replicate? Do you have any documentation on how the LDAP works on local account lookups?

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Re: Preventing backscatter

sayso wrote:

Is it possible to read the remote LDAP database rather than replicate?

Sure, just make sure OpenLDAP is not listening on 127.0.0.1 only and accessible from your backup mx server (firewall).

sayso wrote:

Do you have any documentation on how the LDAP works on local account lookups?

Check /etc/postfix/ldap/*.cf on iRedMail server.

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