Win7 ping first ICMPv6 packet has the Router Alert option

[Tassos Chatzithomaoglou]

I'm trying to find out why the last few weeks one of my Win7 machines, when doing an IPv6 ping, sends the first ICMPv6 packetwith a HbH header (IPv6 Router Alert, MLD), which leads to this packet being dropped somewhere in the path.


C:\Users\Tassos>ping -6 www.google.com

Pinging www.google.com [2a00:1450:4017:801::1012] with 32 bytes of data:
Request timed out.
Reply from 2a00:1450:4017:801::1012: time=62ms
Reply from 2a00:1450:4017:801::1012: time=61ms
Reply from 2a00:1450:4017:801::1012: time=49ms

Next header: IPv6 hop-by-hop option (0)
Hop-by-Hop Option
Next header: ICMPv6 (58)
Length: 0 (8 bytes)
IPv6 Option (Router Alert)
Type: Router Alert (5)
Length: 2
Router Alert: MLD (0)
IPv6 Option (PadN)
Type: PadN (1)
Length: 0
PadN: <MISSING>
Internet Control Message Protocol v6
Type: Echo (ping) request (128)


Other Win7, Win8, WinXP machines do not show that behavior.

C:\Users\Tassos>ping -6 www.google.com

Pinging www.google.com [2a00:1450:4017:801::1012] with 32 bytes of data:
Reply from 2a00:1450:4017:801::1012: time=51ms
Reply from 2a00:1450:4017:801::1012: time=49ms
Reply from 2a00:1450:4017:801::1012: time=53ms
Reply from 2a00:1450:4017:801::1012: time=47ms


Any idea?
I'm guessing an update or a new program/driver installation might have caused it, but i haven't found anything related.


-- 
Tassos