Gmail MX over IPv6

James Cloos cloos at
Mon Jun 18 02:11:23 CEST 2012

>>>>> "WSR" == Wolfgang S Rupprecht <wolfgang.rupprecht at> writes:

WSR> I got a hardfail from gmail.  Their SPF parsing for IPv6 is messed
WSR> up.  Maybe the "::" notation scewed up a string compare to
WSR> ":0:0:0:" or ":0:0:0:0:"?

I can confirm that.  I have a ip6: netblock in my spf and my outgoing
box's ipv6 is typically ascii-fied with a ::.  When I configure my
MTA to prefer ipv6 for outgoing, goog shows an spf fail.  When the MTA
uses ipv4 goog is happy.

I can see three possibilities:

  Their spf parses doesn't grok ip6: tagged entries at all.

  It doesn't handle addr/prefix notation for ipv6.

  It cannot compare explicit vs :: notation.

James Cloos <cloos at>         OpenPGP: 1024D/ED7DAEA6

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