6to4 vs 6in4

[Mangix]

i'm wondering whether or not 6in4 is actually better than 6to4. the reason i ask is because the 6to4 relay address (192.88.99.1) is set up by hurricane electric(according to a traceroute) and it's autoconfigured. i've been using it for a month and have had no problems. not really willing to go back to 6in4 but if i do, what are the advantages?

[kcochran]

Predictability.

192.88.99.0/24 and 2002::/16 are announced as anycast addresses.  Multiple organizations announce these prefixes.  You're in the happy position of seeing our announcement for 192.88.99.0/24 as best from your location.  However, depending on what your provider's routing table looks like, it's possible that the 192.88.99.0/24 block isn't sourced from the same location as your 'best' 6in4 tunnelserver location.  You also have no guarantee that the side you're trying to contact has a nearby route for 2002::/16.  Their metrics could wind up sending it via the other side of the planet.

Basically 6to4 is a shot in the dark.  When we put up our relays all over the place, it became much better, but it's still a shot in the twilight.  There's something to be said for a deterministic network configuration.  It's far easier to troubleshoot.

[snarked]

Also, 6to4 relies on IPv4 routing (especially in 6to4 to 6to4) while 6in4 relies on IPv6 native routing to the tunnel gateway (then IPv4 for transit across the tunnel).

6to4 has one strength:  Automatic allocation of a /48 network to anyone who has a IPv4 address.  6in4 is a native suballocation of IPv6.

[Mangix]

i just did another traceroute of 192.88.99.1 and now some website called nlayer.com is providing the relay. funny because i get latencies of around 100ms with them while 72.52.104.74 gives me 12ms... time to go back to 6in4.

[mtindle]

i just did another traceroute of 192.88.99.1 and now some website called nlayer.com is providing the relay. funny because i get latencies of around 100ms with them while 72.52.104.74 gives me 12ms... time to go back to 6in4.

Can you let us know who your ISP is?  Or provide your traceroute to 192.88.99.1?   We can try to help out depending on our peering relationship with your ISP.  No guarantees though.  And as Kelly mentioned, the 6in4 is going to be a more stable route.

[Mangix]

i just did another traceroute of 192.88.99.1 and now some website called nlayer.com is providing the relay. funny because i get latencies of around 100ms with them while 72.52.104.74 gives me 12ms... time to go back to 6in4.

Can you let us know who your ISP is?  Or provide your traceroute to 192.88.99.1?   We can try to help out depending on our peering relationship with your ISP.  No guarantees though.  And as Kelly mentioned, the 6in4 is going to be a more stable route.

sure. my isp is AT&T and i'm using their ADSL service. here's the traceroute:

Code Select Expand

Tracing route to 192.88.99.1 over a maximum of 30 hops

  1     1 ms    <1 ms    <1 ms  10.2.2.1
  2    35 ms    11 ms    19 ms  bras40-l0.pltnca.sbcglobal.net [151.164.184.120]

  3    29 ms    19 ms    35 ms  64.164.107.2
  4    28 ms    33 ms    11 ms  151.164.93.237
  5    30 ms    13 ms    13 ms  151.164.54.185
  6    37 ms    13 ms    12 ms  asn4436-nlayer.pxpaca.sbcglobal.net [151.164.46.
70]
  7    48 ms    27 ms    15 ms  ae0-70g.cr1.pao1.us.nlayer.net [69.22.153.18]
  8    34 ms    37 ms    15 ms  ae1-60g.cr1.sfo1.us.nlayer.net [69.22.143.169]
  9    27 ms    28 ms    50 ms  xe-0-0-3.cr1.slc1.us.nlayer.net [69.22.142.96]
10    62 ms    68 ms    80 ms  xe-5-2-0.cr1.ord1.us.nlayer.net [69.22.142.101]

11    89 ms    64 ms    76 ms  ae1-30g.ar1.ord1.us.nlayer.net [69.31.111.134]
12    91 ms    64 ms    80 ms  as19255.ge-0-0-42-107.ar1.ord1.us.nlayer.net [69
.31.111.26]
13    91 ms    65 ms    94 ms  192.88.99.1

Trace complete.]/code] i wish i could provide a traceroute prior to this when 192.88.99.1 went through Hurricane Electric's routers but sadly i did not save it. i believe it went through 7 or 8 hops.

[mtindle]

sure. my isp is AT&T and i'm using their ADSL service. here's the traceroute:

Code Select Expand

Tracing route to 192.88.99.1 over a maximum of 30 hops

  1     1 ms    <1 ms    <1 ms  10.2.2.1
  2    35 ms    11 ms    19 ms  bras40-l0.pltnca.sbcglobal.net [151.164.184.120]

  3    29 ms    19 ms    35 ms  64.164.107.2
  4    28 ms    33 ms    11 ms  151.164.93.237
  5    30 ms    13 ms    13 ms  151.164.54.185
  6    37 ms    13 ms    12 ms  asn4436-nlayer.pxpaca.sbcglobal.net [151.164.46.
70]
  7    48 ms    27 ms    15 ms  ae0-70g.cr1.pao1.us.nlayer.net [69.22.153.18]
  8    34 ms    37 ms    15 ms  ae1-60g.cr1.sfo1.us.nlayer.net [69.22.143.169]
  9    27 ms    28 ms    50 ms  xe-0-0-3.cr1.slc1.us.nlayer.net [69.22.142.96]
10    62 ms    68 ms    80 ms  xe-5-2-0.cr1.ord1.us.nlayer.net [69.22.142.101]

11    89 ms    64 ms    76 ms  ae1-30g.ar1.ord1.us.nlayer.net [69.31.111.134]
12    91 ms    64 ms    80 ms  as19255.ge-0-0-42-107.ar1.ord1.us.nlayer.net [69
.31.111.26]
13    91 ms    65 ms    94 ms  192.88.99.1

Trace complete.
i wish i could provide a traceroute prior to this when 192.88.99.1 went through Hurricane Electric's routers but sadly i did not save it. i believe it went through 7 or 8 hops.

Nope, that's perfect.  We have some folks over at AT&T we can ponder over this with.  I also use AT&T at home and my first hop is in Pleasanton, CA :)  So I'll be able to track this down with them from both sides of the fence.

Thanks!

[Mangix]

sorry for reviving this topic instead of making a new one but i have a question about 6to4 again. since i don't like having to keep updating the IPv4 endpoint for my tunnel, is there any way to access Hurricane Electric's 6to4 server without using 192.88.99.1? I ask because that IP still directs me to nlayer's server(which a quick search indicates that it's located in chicago when i'm in california :o). i do recall that even though 192.88.99.1 is the default address, others can be used. any thoughts?

[broquea]

The IPs for the relays are not published because the user is expected to use the anycasted v4 address. Also cuts down on n users bombarding a single relay, or one being targeted.

[snarked]

Network topology is not necessarily the same as geographic topology.  If you're being routed from California to Illinois, that's because that particular gateway is (supposedly) the closest to you (in router hops if not latency).