Postfix IPv6 Support
Postfix 2.2 introduces support for the IPv6 (IP version 6)
protocol. IPv6 support for older Postfix versions was available as
an add-on patch. The section "
Postfix <2.2 IPv6 support" below discusses the differences
between these implementations.
The main feature of interest is that IPv6 uses 128-bit IP
addresses instead of the 32-bit addresses used by IPv4. It can
therefore accommodate a much larger number of hosts and networks
without ugly kluges such as NAT. A side benefit of the much larger
address space is that it makes random network scanning impractical.
Postfix uses the same SMTP protocol over IPv6 as it already
uses over the older IPv4 network, and does AAAA record lookups in
the DNS in addition to the older A records. Information about IPv6
can be found at
This document provides information on the following topics: