[Indimail-support] Double double colon in IPv6 address in Received header

[Adrian O. <ad...@of...>]

We ran into a DKIM validation problem today that appears to be caused by
an IPv6 problem in the Received header:

A message coming in from the system 2a00:1de0:0:203::22 caused these
header to be added:

  Received: (indimail 19110 invoked from 2a00:1de0::203::22 by
  host services.offerman.com by uid 555);
  Fri, 21 Aug 2015 21:23:16 +0200
  ...
  Received: from mx2.parkstad-it.nl (2a00:1de0::203::22)
    by 0 with ESMTPS; Fri, 21 Aug 2015 21:23:16 +0200
  Received-SPF: fail (0: SPF record at parkstad-it.nl does not
  designate 2a00:1de0:0000:0000:0000:0000:0000:0203 as permitted
  sender)

The address in the Received headers gets a double double colon, which
makes it an invalid address. And then the ::22 ending is interpreted as
a port number? and stripped from the address in the SPF header.

Something fishy going on here... :-)