Gmail MX over IPv6

Pim van Pelt pim at
Thu Jun 21 09:48:32 CEST 2012

Hoi Mansoor,

2012/6/21 Bernhard Schmidt <berni at>:
> Am 21.06.2012 09:28, schrieb Mansoor Nathani:
> Hi,
>> I noticed it seems to be picking up some ip / address info from an IPv6
>> tunnel to Hurricane Electric.
>> I never configured this host with any such IPv6 information however.
It seems you are in a hostile ethernet environment where you do not
control all nodes, and one of them is sending router advertisements.
I've always been upset with Linux for accepting RA by default. You may
want to consider:
# sysctl -w net.ipv6.conf.default.accept_ra=0

and turning on accept_ra only if you know your network environment.
That will save you from surprises like this one.

Pim van Pelt <pim at>

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