IPv6

[fanf]

traceroute6 to ftp.heanet.ie (2001:770:18:2::1:100)
from 2001:630:200:8120:20e:cff:fe09:a58a, 30 hops max, 12 byte packets
 1  route-ipv6.cam.ac.uk  0.432 ms  0.284 ms  0.321 ms
 2  gi9-0.cambridge-bar.ja.net  0.300 ms *  0.456 ms
 3  pos10-0.lond-scr.ja.net  4.024 ms  3.793 ms  3.833 ms
 4  po6-0.lond-scr3.ja.net  4.023 ms  3.801 ms  3.820 ms
 5  po0-0.geant-gw1.ja.net  4.161 ms  4.052 ms  4.070 ms
 6  janet.uk1.uk.geant.net  4.285 ms  4.176 ms  4.187 ms
 7  uk.ie1.ie.geant.net  17.654 ms  17.544 ms  17.561 ms
 8  heanet-gw.ie1.ie.geant.net  17.651 ms  17.530 ms  17.686 ms
 9  hyperion-gige5-2.bh.core.hea.net  18.152 ms  18.043 ms  17.936 ms
10  ftp.ipv6.heanet.ie  17.777 ms  17.792 ms  17.812 ms

Comments

[acronym.livejournal.com]

Nifty, but what does it mean for us users? I'm almost entirely ignorant of how IPv6 affects me. (Sorry to be so vaguee :) )

[fanf]

We currently support IPv6 on a few networks, including the CS staff network but notably not the main service network on which Hermes and ppsw live. I had to get Sesame moved from the 8 subnet to the 12 subnet to get IPv6 connectivity. The point of this is to see how well email (and Exim in particular) works in practice on a dual-stack host.

Apart from the bigger address space it has some nice features, including autoconfiguration. My IPv4 setup on this machine is:

ifconfig_em0="131.111.12.4 netmask 255.255.255.0"
defaultrouter="131.111.12.62"

but for IPv6 it's just

ipv6_enable="YES"

There's also more IPsec integration, better IP option handling, more sane fragmentation handling, and supposedly better renumbering and mobility support. I'd generally expect it to be below the radar of anyone who isn't a sysadmin or network engineer.

[techiebloke.livejournal.com]

My main box has been dual stack (via stf) for ages. I haven't spotted any problems with exim.

Mind you, I get bugger all mail from IPv6 hosts; and even less TLS encrypted mail. Go on, send me some email, and I'll bump the count up ;-)

[bellinghman.livejournal.com]

You trying to finger young Brian, then?

[fanf]

Yes. This IPv6 thing is all his fault.

[natural20.livejournal.com]

Excellent, good to know that it's working, although I notice you're going over Geant, which would poke holes in my theory that Janet is properly dual stacked in Dublin. Must check the routing policy in there...

But yeah, er, we have Exim working perfectly fine in v6, just remember to whilelist the address space so the RBLs don't get you.

[fanf]

Yeah, I wondered about the geant thing. It's interesting to compare the IPv4 route:

traceroute to ftp.heanet.ie (193.1.219.100), 64 hops max, 44 byte packets
 1  route-12.cam.ac.uk (131.111.12.62)  0.294 ms  0.292 ms  0.207 ms
 2  route-enet-3.cam.ac.uk (192.153.213.193)  0.279 ms  0.313 ms  0.448 ms
 3  cambridge-bar.ja.net (146.97.40.49)  0.168 ms  0.313 ms  0.198 ms
 4  po10-0.lond-scr.ja.net (146.97.35.5)  3.660 ms  3.433 ms  3.448 ms
 5  po6-0.lond-scr3.ja.net (146.97.33.30)  3.785 ms  3.683 ms  3.696 ms
 6  po2-0.dublin-bar.ja.net (146.97.35.30)  16.527 ms  16.426 ms  16.440 ms
 7  146.97.40.134 (146.97.40.134)  16.516 ms  16.552 ms  16.439 ms
 8  deimos-gige5-3.cwt.core.hea.net (193.1.195.161)  16.653 ms  16.534 ms  16.438 ms
 9  hyperion-gige5-0.bh.core.hea.net (193.1.195.85)  16.903 ms  17.171 ms  16.939 ms
10  mantova-gige1-2.bh.access.hea.net (193.1.196.122)  17.154 ms  17.174 ms  17.064 ms
11  calpurnia-vlan3.bh.access.hea.net (193.1.198.1)  17.777 ms  17.674 ms  18.429 ms
12  ftp.heanet.ie (193.1.219.100)  17.029 ms  17.051 ms  17.063 ms

Interesting that the JaNET part of the route is almost identical but there are extra hops in HEAnet. I'm not sure what to conclude about native IPv6 or otherwise.

[natural20.livejournal.com]

Well, stuff is routing over Geant in v6 because Geant do hardware forwarding, while Janet are still doing software forwarding. Geant have a pretty M20 while Janet are stuck with a GSR. The extra hops aren't really extra hops per se, you have to go through the same boxes in either version, it just shows up differently.

[chess]

The first line is merrily breaking my friends page...

[fanf]

That's LJ's fault for putting everything in a table :-) Stupid HTML.

[ronebofh.livejournal.com]

Just toss a linebreak in the middle of the first line, you.