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neufuse

join:2006-12-06
James Creek, PA
Reviews:
·Comcast

1 edit

IPv6 routing through comcasts' backbone showing up for me now

IPv6 routing through comcasts' backbone showing up for me now

tracert ipv6.google.com

Tracing route to ipv6.l.google.com [2607:f8b0:4002:802::1014]
over a maximum of 30 hops:

1 1 ms 1 ms 1 ms 2002:1803:cd71:e472:226:f2ff:fea1:6532
2 27 ms 27 ms 23 ms 2002:c058:6301::
3 24 ms 24 ms 25 ms ge-2-41-ur03.ndceast.pa.bo.comcast.net [2001:558
:fe14:1::1]
4 25 ms 24 ms 24 ms te-1-3-ar01.ndceast.pa.bo.comcast.net [2001:558:
e0:14::2]
5 24 ms 25 ms 25 ms te-1-3-ar01.philadelphia.pa.bo.comcast.net [2001
:558:e0:3::1]
6 35 ms 35 ms 34 ms te-0-0-0-11-cr01.newyork.ny.ibone.comcast.net [2
001:558:0:f74b::1]
7 28 ms 27 ms 28 ms pos-1-3-0-0-pe01.111eighthave.ny.ibone.comcast.n
et [2001:558:0:f5af::2]
8 32 ms 27 ms 82 ms 2001:559::35a
9 27 ms 27 ms 29 ms 2001:4860::1:0:755
10 128 ms 30 ms 27 ms 2001:4860::8:0:2fd1
11 27 ms 27 ms 27 ms 2001:4860::1:0:5dc
12 40 ms 39 ms 40 ms 2001:4860::1:0:489
13 49 ms 69 ms 51 ms 2001:4860:0:1::164
14 50 ms 40 ms 40 ms atl14s08-in-x14.1e100.net [2607:f8b0:4002:802::1
014]

Trace complete.



whfsdude
Premium
join:2003-04-05
Washington, DC
Reviews:
·Comcast

1 edit

Re: IPv6 routing through comcasts' backbone showing up for me no

Edit: Ignore this, see following posts.
___________________
Looks like you're using 6to4 and Comcast's network as a route.

Expect broken return paths if you're sourcing with 2002::/16

This might completely break if Comcast implementations uRPF on their v6 side.



Napsterbater
Meh
Premium,MVM
join:2002-12-28
Milledgeville, GA
Reviews:
·Windstream

said by whfsdude:

Looks like you're using 6to4 and Comcast's network as a route.

Expect broken return paths if you're sourcing with 2002::/16

Why is that?

said by whfsdude:

This might completely break if Comcast implementations uRPF on their v6 side.

Again why? Comcast setup a 6to4 gateway why would they break it?
--
ASUS M4A79T Deluxe | AMD Phenom II x3 720 BE AM3 w/4 Cores @ 3.41Ghz(OC) | 4Gb DDR3 Memory @ 1600mhz | Sapphire ATI HD4870 1GB 800mhz/1000mhz(OC) | 2x500GB HDD's Raid 0 | Windows 7 Ultimate x64 Build 7600 (RTM) | Windstream DSL 12m (14.9m Sync)/766k


whfsdude
Premium
join:2003-04-05
Washington, DC
Reviews:
·Comcast

said by Napsterbater See ProfileAgain why? Comcast setup a 6to4 gateway why would they break it?

You actually might be right. Although at first glance it looked like the it's source traffic with 2002::/16 to Comcast's link-local router and then onto Comcast's network.

When it should be sending it over IPv4 to Comcast 6to4 anycast node.

However, latency on second hop looks like it is sending over 6to4 properly.

Slightly OT: But if the Linksys WRT610Nv1 does the incorrect behavior as above.


mackey
Premium
join:2007-08-20
kudos:12
reply to neufuse

Just wondering, are you aware of just how much information you gave out with that traceroute? It says your public IPv4 address is 24.3.2XX.113 and you're using a Netgear router, most likely a WNDR3700

/M



Napsterbater
Meh
Premium,MVM
join:2002-12-28
Milledgeville, GA
Reviews:
·Windstream
reply to whfsdude

said by whfsdude:

said by Napsterbater See ProfileAgain why? Comcast setup a 6to4 gateway why would they break it?

You actually might be right. Although at first glance it looked like the it's source traffic with 2002::/16 to Comcast's link-local router and then onto Comcast's network.

When it should be sending it over IPv4 to Comcast 6to4 anycast node.

When on 6to4 and doing a tracert from a system you will not see any IPv4 in the trace even though the traffice is going over IPv4 to 192.88.99.1, Also I see no Link Local address everything is globaly routable, And it is supposed to be sourced from a 2002::/16 address and look just the above trace.
--
ASUS M4A79T Deluxe | AMD Phenom II x3 720 BE AM3 w/4 Cores @ 3.41Ghz(OC) | 4Gb DDR3 Memory @ 1600mhz | Sapphire ATI HD4870 1GB 800mhz/1000mhz(OC) | 2x500GB HDD's Raid 0 | Windows 7 Ultimate x64 Build 7600 (RTM) | Windstream DSL 12m (14.9m Sync)/766k


whfsdude
Premium
join:2003-04-05
Washington, DC
Reviews:
·Comcast

1 edit

Only the router would see the LL of Comcast's router so it wouldn't show up in a traceroute. Nor v4.

The first hop (on the providers net) you would see is a relay. And his first hop past his router didn't look like a relay but I guess it is. It wasn't label as such in the PTR.

What I meant was if he was sourcing 2002::/16 on packets but avoiding passing traffic over the v4 6to4 tun and instead to Comcast's router via LL.

You see this on WRT610N v1's. I know of no other router that has that broken 6to4 implementation.



mackey
Premium
join:2007-08-20
kudos:12

said by whfsdude:

The first hop you would see is a relay. And his first hop past his router didn't look like a relay but I guess it is.

How does it not look like a relay? Look at the IP: 2002:c058:6301::
Strip off the "2002" and you get c058:6301
Convert from hex to decimal and you get 192 88 : 99 01 . Look familiar? It's the 6to4 anycast address 192.88.99.1

/M


whfsdude
Premium
join:2003-04-05
Washington, DC
Reviews:
·Comcast

Yeah when I initially read it, I thought "24 ms 24 ms 25 ms ge-2-41-ur03.ndceast.pa.bo.comcast.net [2001:558
:fe14:1::1]" was the first hop outside of the network as the line break was confusing.

But yes, the implementation I described does occur on the WRT610N and it's pretty nasty.



Napsterbater
Meh
Premium,MVM
join:2002-12-28
Milledgeville, GA
reply to whfsdude

2002:c058:6301:: Is the relay. That should be the first hop on a 6to4 connection. It cant have a PTR because no one owns that address just like 192.88.99.1, they are set aside for 6to4.



mackey
Premium
join:2007-08-20
kudos:12
reply to whfsdude

said by whfsdude:

But yes, the implementation I described does occur on the WRT610N and it's pretty nasty.

It sounds like it! I'm sure glad I don't have to deal with that...

/M


whfsdude
Premium
join:2003-04-05
Washington, DC

said by mackey:

It sounds like it! I'm sure glad I don't have to deal with that..

Solution was dd-wrt.


mackey
Premium
join:2007-08-20
kudos:12

1 recommendation

said by whfsdude:

Solution was dd-wrt.

Nah, I dropped Linksys when they dropped Linux from the WRT54G. I mainly use D-Link and Netgear nowadays; D-Link when I want to leave it as a router running stock firmware and Netgear when I want to flash OpenWRT and make it be pretty much everything but a router...

/M