nanog mailing list archives
Re: Using /126 for IPv6 router links
From: "Dale W. Carder" <dwcarder () wisc edu>
Date: Wed, 27 Jan 2010 23:24:48 -0600
On Jan 27, 2010, at 3:19 PM, Igor Gashinsky wrote:
you face 2 major issues with not using /127 for PtP-type circuits: 1) ping-ponging of packets on Sonet/SDH links Let's say you put 2001:db8::0/64 and 2001:db8::1/64 on a PtP interface, and somebody comes along and ping floods 2001:db8::2, those packets will bounce back and forth between the 2 sides of the link till TTL expires (since there is no address resolution mechanism in PtP, so it just forwards packets not destined for "him" on).
Following this, IPv4 /30 would have the same problem vs /31?
2) ping sweep of death Take the same assumption for addressing as above, and now ping sweep 2001:db8::/64... if the link is ethernet, well, hope you didn't have any important arp entries that the router actually needed to learn.
Wouldn't this affect *all* /64's configured on a router, not just point to point links? Time for glean rate limiting. If you were really concerned, you could hard code static NDP entries, as I think someone else pointed out. Dale
Current thread:
- RE: Using /126 for IPv6 router links, (continued)
- RE: Using /126 for IPv6 router links Igor Gashinsky (Jan 26)
- Re: Using /126 for IPv6 router links Steve Bertrand (Jan 26)
- Re: Using /126 for IPv6 router links Grzegorz Janoszka (Jan 27)
- RE: Using /126 for IPv6 router links TJ (Jan 27)
- RE: Using /126 for IPv6 router links Pekka Savola (Jan 26)
- Re: Using /126 for IPv6 router links Mark Smith (Jan 26)
- Re: Using /126 for IPv6 router links Jim Burwell (Jan 27)
- RE: Using /126 for IPv6 router links Igor Gashinsky (Jan 27)
- Re: Using /126 for IPv6 router links Steve Bertrand (Jan 27)
- Re: Using /126 for IPv6 router links Igor Gashinsky (Jan 27)
- Re: Using /126 for IPv6 router links Dale W. Carder (Jan 27)
- Re: Using /126 for IPv6 router links David Barak (Jan 28)
- Re: Using /126 for IPv6 router links Igor Gashinsky (Jan 28)
- Re: Using /126 for IPv6 router links Bill Stewart (Jan 29)
- Re: Using /126 for IPv6 router links Leo Bicknell (Jan 25)
- Re: Using /126 for IPv6 router links Owen DeLong (Jan 25)
- Re: Using /126 for IPv6 router links Christopher Morrow (Jan 25)
- Re: Using /126 for IPv6 router links Mark Smith (Jan 26)
- Re: Using /126 for IPv6 router links David Barak (Jan 26)
- Re: Using /126 for IPv6 router links Mark Smith (Jan 26)
- Re: Using /126 for IPv6 router links Grzegorz Janoszka (Jan 26)