Don't take my comments the wrong way:

Certainly setting up a 6to4 gateway is a trivial task and if you've got v6 connectivity then you might as well do it - grab a spare Cisco router, plumb it in to your network with v4,v6, then pretty much add the bits below.

Teredo is a bit harder but also useful because it works through NAT (6to4 assumes it's on the CPE running NAT).  Teredo requires something running Linux/FreeBSD/etc.  A bit annoying.

ipv6 unicast-routing
!
!
! The IPv4,v6 address on Lo2002 are the special 6to4 magic ones.  
!
interface Loopback2002
 ip address 192.88.99.1 255.255.255.0
 ipv6 address 2002:C058:6301::1/128
!         
interface Tunnel2002
 description anycast 6to4 Relay Interface
 no ip address
 no ip redirects
 ipv6 unnumbered Loopback2002
 ipv6 mtu 1280
 tunnel source Loopback2002
 tunnel mode ipv6ip 6to4
 tunnel path-mtu-discovery
!       
ipv6 route 2002::/16 Tunnel2002

and make sure 2002::/16 and 192.88.99.0/24 are leaked into your IGP so it can be found or add statics or whatever works for you.

MMC




On 09/03/2009, at 1:42 PM, Joe Abley wrote:


On 8 Mar 2009, at 23:08, Matthew Moyle-Croft wrote:

Given with 6to4 you don't control the return gateway (ie.  where the other end uses to send packets back to you) does it matter that much?

The same logic goes for content providers; whether your revenue comes from end users or from content, it still makes more sense to run the relay yourself than to trust the packets to someone else (someone that you can't predictably identify, even, which surely will be lots of fun to troubleshoot).

More fundamentally, if running your own 6to4 relay is a trivial exercise, as I suspect it will be for anybody here who has a dual-stack core, does it make more sense to spend time considering whether to do it than just to do it?


Joe


-- 
Matthew Moyle-Croft Internode/Agile Peering and Core Networks
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