[152172] in North American Network Operators' Group
RE: Automatic IPv6 due to broadcast
daemon@ATHENA.MIT.EDU (Matthew Huff)
Mon Apr 16 14:25:49 2012
From: Matthew Huff <mhuff@ox.com>
To: 'Anurag Bhatia' <me@anuragbhatia.com>, 'NANOG Mailing List'
<nanog@nanog.org>
Date: Mon, 16 Apr 2012 14:24:51 -0400
In-Reply-To: <CAJ0+aXay94WmoCqOtx_NydaRVf9y9xKQXiQBHxQZiYs4-STU_Q@mail.gmail.com>
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
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To completely disable ipv6 in Redhat:
1) Modify /etc/modprobe.conf (add) =20
=20
alias ipv6 off
alias net-pf-10 off
options ipv6 disable=3D1
2) Modify /etc/sysconfig/network (add)
NETWORKING_IPV6=3Dno
I usually also add
NOZEROCONF=3Dyes=20
That should completely disable ipv6 in Redhat 5.x
----
Matthew Huff=A0 | 1 Manhattanville Rd
Director of Operations=A0=A0=A0| Purchase, NY 10577
OTA Management LLC | Phone: 914-460-4039
aim: matthewbhuff=A0 | Fax:=A0=A0 914-460-4139
> -----Original Message-----
> From: Anurag Bhatia [mailto:me@anuragbhatia.com]
> Sent: Monday, April 16, 2012 2:10 PM
> To: NANOG Mailing List
> Subject: Automatic IPv6 due to broadcast
>=20
> Hello everyone
>=20
>=20
>=20
> Just got a awfully crazy issue. I heard from our support team about
> failure of whois during domain registration. Initially I thought of
> port 43 TCP block or something but found it was all ok. Later when ran
> whois manually on server via terminal it failed. Found problem that
> server was connecting to whois server - whois.verisign-grs.com. I was
> stunned! Server got IPv6 and not just that one - almost all. This was
> scary - partial IPv6 setup and it was breaking things.
>=20
> In routing tables, routes were all going to a router which I recently
> setup for testing. That router and other servers are under same switch
> but by no means I ever configured that router as default gateway for
> IPv6. I found option of "broadcast" was enabled on router for local
> fe80... address and I guess router broadcasted IPv6 and somehow (??)
> all servers found that they have a IPv6 router on LAN and started =
using
> it - automated DHCP IPv6?
>=20
> I wonder if anyone else also had similar issues? Also, if my guesses
> are correct then how can we disable Red Hat distro oriented servers
> from taking such automated configuration - simple DHCP in IPv6 =
disable?
>=20
>=20
>=20
>=20
> Thanks
>=20
> --
>=20
> Anurag Bhatia
> anuragbhatia.com
> or simply - http://[2001:470:26:78f::5] if you are on IPv6 connected
> network!
>=20
> Twitter: @anurag_bhatia <https://twitter.com/#!/anurag_bhatia>
> Linkedin: http://linkedin.anuragbhatia.com
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