Win7 ping first ICMPv6 packet has the Router Alert option

[Marco Sommani]

Not all ICMPv6 packets are pings (type 128 or 129). If your ICPv6 packet is an MLD Report (type 131 or 143), then it must be preceded by a HbH header.

Marco

On 10/mar/2013, at 13:14, Tassos Chatzithomaoglou wrote:

> 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
>