Postfix mynetworks

Richard Esplin richard at
Fri Mar 13 12:51:32 MDT 2009

In the default Postfix for Debian Lenny, the mynetworks line looks 
like this:

mynetworks = [::ffff:]/104 [::1]/128

This is what I understand:
* The It is classic CIDR IPv4 notation, which I am comfortable 
* The rest is CIDR IPv6 notation.
* The :: is a group of zeros in an IPv6 address.
* The ::1/128 is the IPv6 loopback (thank you Wikipedia).
* IPv6 addresses need to be in brackets because the ":" is reserved for other 
config syntax (a common convention--not just Postfix, and not just because of 
the port identifier).

My question is:
* Why include ::ffff:

I thought about asking on #utah, but I want this in the plug archives. Then 
next time I ask this question, Google might help.



More information about the PLUG mailing list