IPV6 BGP flapping caused by duplicate OSPFV3 router ID

[Mike Leber]

While not necessarily your problem, make sure you add IPv6 addresses to 
your router loopback interfaces, just like you do for IPv4.

Also make sure to add IPv6 addresses for any interfaces you enable IPv6 
on, otherwise they may come up in OSFP with IPv6 link local addresses.

(Just mentioning these two because I've seen stuff like this before.)

Though you almost certainly do, if you don't have a loopback interface 
configured and you run OSPF, you should read about why you want one (the 
OSPF and BGP tutorials for Cisco and lots of other vendors cover this).
(This also can cause the problem you mention below if you happen to have 
multiple routers configured for either anycast or you use the same 
RFC1918 IP for an internal well known service like caching DNS.  i.e. no 
loopback means the same IP may be picked on multiple routers as the 
router ID if you have the same IP on multiple routers.)

Mike.

Herlianto wrote:
> Hi All,
> 
> We have deployed IPV6 over IPV4 tunnel, but at some site we facing the 
> problem for BGP and OSPFV3.
> 
> The BGP Flapping and at the log there is command as shown below :
> Aug  9 08:08:39.089: %OSPFv3-4-DUP_RTRID_AREA: Detected router with 
> duplicate router ID x.x.x.x in area 0
> Aug  9 08:09:46.644: %OSPFv3-4-DUP_RTRID_AREA: Detected router with 
> duplicate router ID x.x.x.x in area 0
> 
> for OSPF V3  with the command : #show ipv6 ospf neighbor there is some 
> different interface tunnel but the neighbor ID is same
> 
> Is there any experience and any suggestion to solve it ?
> 
> Thanks for your kind attention and cooperation.
> -- 
> 
> 
> _H e r l y_

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