To completely disable ipv6 in Redhat: 1) Modify /etc/modprobe.conf (add) alias ipv6 off alias net-pf-10 off options ipv6 disable=1
2) Modify /etc/sysconfig/network (add) NETWORKING_IPV6=no I usually also add NOZEROCONF=yes That should completely disable ipv6 in Redhat 5.x ---- Matthew Huff | 1 Manhattanville Rd Director of Operations | Purchase, NY 10577 OTA Management LLC | Phone: 914-460-4039 aim: matthewbhuff | Fax: 914-460-4139 > -----Original Message----- > From: Anurag Bhatia [mailto:m...@anuragbhatia.com] > Sent: Monday, April 16, 2012 2:10 PM > To: NANOG Mailing List > Subject: Automatic IPv6 due to broadcast > > Hello everyone > > > > 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. > > 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? > > 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? > > > > > Thanks > > -- > > Anurag Bhatia > anuragbhatia.com > or simply - http://[2001:470:26:78f::5] if you are on IPv6 connected > network! > > Twitter: @anurag_bhatia <https://twitter.com/#!/anurag_bhatia> > Linkedin: http://linkedin.anuragbhatia.com
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