nanog mailing list archives
Re: using "reserved" IPv6 space
From: Owen DeLong <owen () delong com>
Date: Mon, 16 Jul 2012 23:44:42 -0700
On Jul 16, 2012, at 11:16 PM, Jimmy Hess wrote:
On 7/17/12, Karl Auer <kauer () biplane com au> wrote: [snipI'm not sure I follow the logic there. If the anycast router changes the packet will be resent to the new subnet anycast router eventually (assuming some layer cares enough about the packet to resend it). The "last known hardware address" doesn't matter any more or less in this scenario than it does in any other routing situation.The pertinent discussion is not about "any other routing situation"; it's about first hop redundancy. The "last known hardware address" is in the NDP table, so the packet retransmissions likely wind up in the same place
NUD should actually take care of that.
Another problem is the subnet anycast address may find unwanted routers that have to listen on it, including routers with only one interface and incomplete routing info, and including some unauthorized 5-port IPv6 router someone smuggled into the building and plugged in somewhere.
Yep.
By contrast, a real FHRP that implements failover either uses a virtual hardware address, or a 'gratuitous arp' type mechanism, so the packet retransmissions will go to the live failover partner.
The whole concept of gratuitous arp is strictly IPv4. Owen
Current thread:
- Re: using "reserved" IPv6 space, (continued)
- Re: using "reserved" IPv6 space Owen DeLong (Jul 16)
- Re: using "reserved" IPv6 space Seth Mos (Jul 17)
- Re: using "reserved" IPv6 space Rajendra Chayapathi (rchayapa) (Jul 16)
- Re: using "reserved" IPv6 space Oliver (Jul 16)
- Re: using "reserved" IPv6 space Rajendra Chayapathi (rchayapa) (Jul 16)
- Re: using "reserved" IPv6 space Matt Addison (Jul 16)
- Re: using "reserved" IPv6 space Karl Auer (Jul 16)
- Re: using "reserved" IPv6 space Jimmy Hess (Jul 16)
- Re: using "reserved" IPv6 space Karl Auer (Jul 16)
- Re: using "reserved" IPv6 space Jimmy Hess (Jul 16)
- Re: using "reserved" IPv6 space Owen DeLong (Jul 16)
- Re: using "reserved" IPv6 space Karl Auer (Jul 16)
- Re: using "reserved" IPv6 space Owen DeLong (Jul 16)
- Re: using "reserved" IPv6 space Karl Auer (Jul 17)
- Re: using "reserved" IPv6 space Matt Addison (Jul 17)
- Re: using "reserved" IPv6 space Doug Barton (Jul 17)
- Re: using "reserved" IPv6 space Owen DeLong (Jul 16)
- Re: using "reserved" IPv6 space Oliver (Jul 17)
- Re: using "reserved" IPv6 space Jimmy Hess (Jul 16)
- Re: using "reserved" IPv6 space -Hammer- (Jul 17)
- Re: using "reserved" IPv6 space Saku Ytti (Jul 17)