nanog mailing list archives

Re: JUNOS forwards IPv6 link-local packets


From: Jack Bates <jbates () brightok net>
Date: Fri, 27 Apr 2012 09:16:17 -0500

On 4/27/2012 8:56 AM, Chris Adams wrote:
I found out by accident yesterday that JUNOS routers will forward IPv6
packets with a link-local source address, in direct opposition of RFC
4291.  To me, this seems to be a security hole that would be useful for
DDoS attackers, giving them a way to send traffic that is difficult to
trace back to the source.  I try to be a good "net neighbor", using uRPF
wherever possible (and other filters elsewhere) to make sure all packets
coming from my network at least look valid, but this goes right by that.


Theoretically you can do a discard route and then uRPF should work with it. I'm not sure if it will kill the RE traffic, though. If it does, you'll have to have fail filters to allow it. :(


Jack


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