IPv6 packet losses - 20% normal on traceroute6s?

[Ben Winslow]

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On Sat, 2002-03-02 at 23:25, Pekka Savola wrote:
> On Sat, 2 Mar 2002, Michael Kjorling wrote:
> > When I use the 6tap IPv6 traceroute service, it seems like I get a
> > consistent some 20% packet loss. Pinging the same host from the same
> > site does not show anywhere near this loss.
> >=20
> > Even routers very close to 6tap's server (first and second hop shows
> > one out of three dropped packets each) show this problem. Tracerouting
> > back to 3FFE:700:20:3::1 (first hop from 6tap towards me), while not
> > giving much information (only three hops being listen, as opposed to
> > six the other way) still shows a rather consistent 33% loss between
> > UUNet's router and 6tap's.
> >=20
> > Is this considered normal?
>=20
> This is most probably caused by hare-brained ICMP error rate-limiting; yo=
u=20
> can detect old Cisco's from the crowd as they drop about every other=20
> traceroute.  It has been fixed in recently released 12.2(8)T, and remedie=
d=20
> in the ICMP6 draft standard candidate draft.
>=20
> --=20
> Pekka Savola                 "Tell me of difficulties surmounted,
> Netcore Oy                   not those you stumble over and fall"
> Systems. Networks. Security.  -- Robert Jordan: A Crown of Swords

Indeed, this rate limiting is unfortunately on by default.  If you
happen to have such a router and upgrading the IOS isn't feasable, you
can work around it with 'ipv6 icmp error-interval 0' in configuration
mode.

I don't think it's very likely that people are going to be DoSing IPv6
routers just yet...  At least I hope not.

--=20
Ben Winslow (rain@bluecherry.net) : When you are in it up to your
       System Administrator       : ears, keep your mouth shut. =20
   Bluecherry Internet Services   :=20
    http://www.bluecherry.net/    :=20
          (573) 592-0800          :=20

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