Translations:Complete Virtual Mail Server/Postfix additions/73/en

A common throughput limiter is the use of DNS lookups. These can be slow and can be an issue far before processes, CPU or memory are the issue. One lookup per message is required at the very least per message, a server MX record needs to be found. A local caching DNS server could help enormously here and packages such as or even a full  setup should be used.