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Performance tuning

If you're running a busy mail server (many inbound/outbound emails every day), you can follow below suggestions for better performance.

Setup a DNS server in LAN or localhost to cache DNS queries

Mail services heavily rely on DNS service and perform many many DNS queries, a cache DNS server in LAN or localhost helps A LOT:

• It speeds up DNS queries. This helps a lot to speed up mail flow.
• It reduces DNS queries to DNSBL servers, so that you can continue using their excellent service without exceeding the max query limit.

Enable postscreen service to help reduce spam

• Enable postscreen service

If you don't want to use postscreen service, you can enable DNSBL service instead, it helps a lot too. Although both postscreen and pure DNSBL services uses the same DNSBL servers, but postscreen offers additional solutions to reduce spam, so postscreen is better.

postscreen and DNSBL service help catch a lot spam before putting the spams in local mail queue, so they save much system resource.

Update Amavisd + Postfix config files to process more emails concurrently

• Process more emails concurrently