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Ticket ID: SIXXS #1491061 Ticket Status: User PoP: demuc02 - M-net Telekommunikations GmbH (Muenchen)
Routing problems between demuc02 and ittrn01
![[de]](/s/countries/de.gif) Shadow Hawkins on Saturday, 03 April 2010 19:52:55
Hello!
For approx. a week, I'm experiencing strange routing problems between two of my
tunnels, namely T22466 (which terminates on demuc02) and T21777 (which
terminates on ittrn01). Approx. 2/3 of all connections time out eventually, or
fail with "no route to host" error messages, then again, some connections
succeed. There doesn't seem to be any pattern to it; some SSH and IMAP
connections succeed and stay alive for days, whereas most things UDP fail almost
continuously. When I try to test this, e.g. by connecting two netcats together,
everything seems to work (or I was just lucky...), be it TCP or UDP.
The issue seems only to be between those two PoPs -- as far as I can tell,
everything which goes against any other IPv6 destination works flawlely (e.g.
Googlev6, KAME, SixXS itself, and a few others which I could think of).
I've experienced the same problems from T21600, which also terminates on ittrn01
(always towards T22466).
This also shows in the pings and traceroutes:
-> ping probes from T22466 to the ittrn01 PoP fail completely -- but only IPCMv6
ones, not regular v4 pings, which go through without and problem.
-> Both kind of pings from T21777 to the demuc02 PoP go through
-> traceroute from T22466 to the ittrn01 PoP seems rather strange and seems to
fail at multiple points (see below), the other direction seems fine, though.
-> The traceroute from T21777 to T22466 looks normal. The other direction fails
miserably (see below).
-> Pings in either direction between those two Tunnels fail completely, but
without error messages, just packet loss.
Sometimes, connection attempts result in ICMP unreachable messages, sometimes,
they go through, sometimes, they simply time out; all in all, about 2/3s to 3/4s
of all attempts fail in some way or the other.
Regards,
Stefan
Routing problems between demuc02 and ittrn01
Shadow Hawkins on Saturday, 03 April 2010 19:53:37
Here's the output of most of the tests that I could think of:
+-------------------+
| Italy --> Germany |
+-------------------+
T21777 -> ittrn01 PoP (v4 and v6)
=====================
PING ittrn01.sixxs.net (213.254.12.34): 56 data bytes
64 bytes from 213.254.12.34: icmp_seq=0 ttl=56 time=54.912 ms
64 bytes from 213.254.12.34: icmp_seq=1 ttl=56 time=54.278 ms
64 bytes from 213.254.12.34: icmp_seq=2 ttl=56 time=54.410 ms
64 bytes from 213.254.12.34: icmp_seq=3 ttl=56 time=54.242 ms
64 bytes from 213.254.12.34: icmp_seq=4 ttl=56 time=55.752 ms
PING6(56=40+8+8 bytes) 2001:1418:100:2ed::2 --> 2001:1418:10:2::2
16 bytes from 2001:1418:10:2::2, icmp_seq=0 hlim=64 time=54.129 ms
16 bytes from 2001:1418:10:2::2, icmp_seq=1 hlim=64 time=53.466 ms
16 bytes from 2001:1418:10:2::2, icmp_seq=2 hlim=64 time=53.846 ms
16 bytes from 2001:1418:10:2::2, icmp_seq=3 hlim=64 time=53.349 ms
16 bytes from 2001:1418:10:2::2, icmp_seq=4 hlim=64 time=53.836 ms
traceroute to ittrn01.sixxs.net (213.254.12.34), 64 hops max, 40 byte packets
1 host110-177-static.95-94-b.business.telecomitalia.it (94.95.177.110) 97.244 ms 98.977 ms 199.167 ms
2 * * *
3 r-pd71-vl19.opb.interbusiness.it (80.18.114.145) 45.374 ms 46.80 ms 45.693 ms
4 172.17.6.181 (172.17.6.181) 54.487 ms 54.247 ms 54.83 ms
5 172.17.7.190 (172.17.7.190) 53.660 ms 53.719 ms 54.440 ms
6 172.17.4.218 (172.17.4.218) 53.78 ms 52.834 ms 52.706 ms
7 itgate-pub.topix.it (194.116.96.4) 54.144 ms 54.493 ms 54.527 ms
8 if-0-0.charleston.CBQ.TRN.itgate.net (213.254.0.13) 53.456 ms 53.254 ms 53.443 ms
9 frejus.ITgate.net (213.254.12.34) 54.70 ms 54.398 ms 54.468 ms
traceroute6 to ittrn01.sixxs.net (2001:1418:10:2::2) from 2001:1418:100:2ed::2, 64 hops max, 12 byte packets
1 frejus.ITgate.net 54.557 ms 53.807 ms 54.597 ms
T21777 -> demuc02 PoP (v4 and v6)
=====================
PING demuc02.sixxs.net (62.245.150.2): 56 data bytes
64 bytes from 62.245.150.2: icmp_seq=0 ttl=52 time=90.177 ms
64 bytes from 62.245.150.2: icmp_seq=1 ttl=52 time=89.507 ms
64 bytes from 62.245.150.2: icmp_seq=2 ttl=52 time=89.847 ms
64 bytes from 62.245.150.2: icmp_seq=3 ttl=52 time=89.919 ms
64 bytes from 62.245.150.2: icmp_seq=4 ttl=52 time=90.014 ms
PING6(56=40+8+8 bytes) 2001:1418:100:2ed::2 --> 2001:a60:0:1:89:2:16:2
16 bytes from 2001:a60:0:1:89:2:16:2, icmp_seq=0 hlim=57 time=96.173 ms
16 bytes from 2001:a60:0:1:89:2:16:2, icmp_seq=1 hlim=57 time=95.647 ms
16 bytes from 2001:a60:0:1:89:2:16:2, icmp_seq=2 hlim=57 time=96.007 ms
16 bytes from 2001:a60:0:1:89:2:16:2, icmp_seq=3 hlim=57 time=95.507 ms
16 bytes from 2001:a60:0:1:89:2:16:2, icmp_seq=4 hlim=57 time=95.268 ms
traceroute to demuc02.sixxs.net (62.245.150.2), 64 hops max, 40 byte packets
1 host110-177-static.95-94-b.business.telecomitalia.it (94.95.177.110) 44.83 ms 98.935 ms 99.567 ms
2 * * *
3 r-pd71-vl19.opb.interbusiness.it (80.18.114.145) 46.83 ms 46.308 ms 46.182 ms
4 172.17.6.177 (172.17.6.177) 51.41 ms 51.508 ms 51.90 ms
5 172.17.6.105 (172.17.6.105) 51.764 ms 52.20 ms 51.502 ms
6 mil52-ibs-resid-6.mil.seabone.net (195.22.205.105) 51.545 ms 51.263 ms 50.584 ms
7 mil14-mil50-racc1.mil.seabone.net (195.22.196.169) 51.525 ms 51.513 ms 52.536 ms
8 so-2-0-0-ycr1.mlu.cw.net (195.22.208.110) 51.51 ms 51.296 ms 51.574 ms
9 ge-3-3-0-1-ycr1.mlu.cw.net (195.2.9.62) 74.933 ms ge-3-2-0-1-ycr2.mlu.cw.net (195.2.9.130) 74.11 ms 73.634 ms
10 so-5-1-0-0-dcr1.fra.cw.net (208.175.232.85) 71.514 ms 71.942 ms 72.289 ms
11 so-5-0-0-zcr2.muc.cw.net (195.2.2.26) 74.336 ms 74.473 ms 73.693 ms
12 mnet-gw.muc.cw.net (62.208.255.150) 157.452 ms 123.947 ms 116.62 ms
13 te1-1.r1.muc2.m-online.net (212.18.6.49) 76.668 ms 76.776 ms 77.182 ms
14 demuc02.sixxs.net (62.245.150.2) 89.558 ms 89.633 ms 89.981 ms
traceroute6 to demuc02.sixxs.net (2001:a60:0:1:89:2:16:2) from 2001:1418:100:2ed::2, 64 hops max, 12 byte packets
1 gw-750.trn-01.it.sixxs.net 54.433 ms 54.48 ms 53.889 ms
2 if-1-12.charleston.CBQ.TRN.ipv6.ITgate.net 53.475 ms 55.239 ms 53.566 ms
3 if-0-1.scooby-monster.core.TRN.ipv6.ITgate.net 54.61 ms 54.262 ms 54.071 ms
4 if-4-0.tango.core.MIL2.ipv6.ITgate.net 57.259 ms 57.624 ms 58.553 ms
5 if-2-0.mambo.core.MIL1.ipv6.ITgate.net 58.78 ms 57.429 ms 57.276 ms
6 tiscali-v6.mix-it.net 58.028 ms 57.527 ms 57.29 ms
7 so-2-1-0.fra22.ip6.tinet.net 68.626 ms 68.082 ms 68.122 ms
8 xe-2-0-0.fra21.ip6.tinet.net 67.657 ms 68.077 ms 68.567 ms
9 xe-0-1-0.fra20.ip6.tinet.net 67.695 ms 68.116 ms 105.665 ms
10 lambdanet.ip6.tinet.net 67.13 ms 67.083 ms 68.14 ms
11 FRA-1-eth200.v6.lambdanet.net 67.155 ms 66.564 ms 67.801 ms
12 FRA-12-eth020-104.v6.lambdanet.net 67.14 ms 67.051 ms 67.157 ms
13 M-net-MUC.v6.lambdanet.net 73.349 ms 73.43 ms 93.767 ms
14 2001:a60:0:1:89:2:16:2 95.523 ms 95.632 ms 95.259 ms
T21777 -> T22466 (v6 only)
================
PING6(56=40+8+8 bytes) 2001:1418:100:2ed::2 --> 2001:a60:f000:b9::2
5 packets transmitted, 0 packets received, 100.0% packet loss
traceroute6 to vaarsuvius.aleturo.com (2001:a60:f000:b9::2) from 2001:1418:100:2ed::2, 64 hops max, 12 byte packets
1 gw-750.trn-01.it.sixxs.net 54.069 ms 54.011 ms 53.622 ms
2 if-1-12.charleston.CBQ.TRN.ipv6.ITgate.net 54.3 ms 55.016 ms 54.623 ms
3 if-0-1.scooby-monster.core.TRN.ipv6.ITgate.net 54.538 ms 54.254 ms 54.607 ms
4 if-4-0.tango.core.MIL2.ipv6.ITgate.net 57.031 ms 58.216 ms 57.543 ms
5 if-2-0.mambo.core.MIL1.ipv6.ITgate.net 59.77 ms 60.36 ms 57.32 ms
6 tiscali-v6.mix-it.net 56.527 ms 57.015 ms 56.873 ms
7 so-2-1-0.fra22.ip6.tinet.net 68.552 ms 68.055 ms 67.179 ms
8 xe-1-1-0.fra23.ip.tinet.net 69.642 ms !N 68.473 ms !N 69.172 ms !N
T21777 -> noc.sixxs.net (v6 only)
=======================
PING6(56=40+8+8 bytes) 2001:1418:100:2ed::2 --> 2001:838:1:1:210:dcff:fe20:7c7c
16 bytes from 2001:838:1:1:210:dcff:fe20:7c7c, icmp_seq=0 hlim=52 time=136.637 ms
16 bytes from 2001:838:1:1:210:dcff:fe20:7c7c, icmp_seq=1 hlim=52 time=137.748 ms
16 bytes from 2001:838:1:1:210:dcff:fe20:7c7c, icmp_seq=2 hlim=52 time=138.006 ms
16 bytes from 2001:838:1:1:210:dcff:fe20:7c7c, icmp_seq=3 hlim=52 time=137.655 ms
16 bytes from 2001:838:1:1:210:dcff:fe20:7c7c, icmp_seq=4 hlim=52 time=137.508 ms
traceroute6 to noc.sixxs.net (2001:838:1:1:210:dcff:fe20:7c7c) from 2001:1418:100:2ed::2, 64 hops max, 12 byte packets
1 gw-750.trn-01.it.sixxs.net 53.998 ms 53.941 ms 53.722 ms
2 if-1-12.charleston.CBQ.TRN.ipv6.ITgate.net 54.763 ms 53.563 ms 54.543 ms
3 if-0-1.scooby-monster.core.TRN.ipv6.ITgate.net 54.089 ms 53.784 ms 54.095 ms
4 if-4-0.tango.core.MIL2.ipv6.ITgate.net 57.007 ms 57.623 ms 57.515 ms
5 tu-611.sar1.London1.Level3.net 84.241 ms 83.436 ms 82.407 ms
6 ip-9-2-0.bar1.Milan1.Level3.net 140.792 ms 107.075 ms 107.103 ms
7 2001:1900:5:2:1::8a 227.207 ms 497.589 ms 83.662 ms
8 2001:6f8:1:0:87:86:77:12 82.891 ms 82.273 ms 82.962 ms
9 2001:6f8:1:0:87:86:77:10 85.264 ms 84.066 ms 84.122 ms
10 2001:6f8:1:0:87:86:77:8 88.449 ms 87.658 ms 87.243 ms
11 2001:6f8:1:0:87:86:77:6 87.542 ms 89.062 ms 86.829 ms
12 2001:6f8:1:0:87:86:77:4 88.932 ms 88.019 ms 88.697 ms
13 2001:6f8:1:0:87:86:77:2 87.517 ms 88.52 ms 88.242 ms
14 2001:6f8:1:0:87:86:77:0 102.654 ms 101.095 ms 101.723 ms
15 2001:6f8:1:0:87:86:77:63 107.929 ms 106.033 ms 106.768 ms
16 2001:6f8:1:0:87:82:50:236 136.254 ms 136.994 ms 136.374 ms
17 2001:838:5:a::2 137.752 ms 138.053 ms 137.763 ms
18 noc.sixxs.net 137.859 ms 138.005 ms 137.349 ms
T21777 -> ipv6.google.com (v6 only)
=========================
PING6(56=40+8+8 bytes) 2001:1418:100:2ed::2 --> 2a00:1450:8001::68
16 bytes from 2a00:1450:8001::68, icmp_seq=0 hlim=55 time=100.073 ms
16 bytes from 2a00:1450:8001::68, icmp_seq=1 hlim=55 time=100.237 ms
16 bytes from 2a00:1450:8001::68, icmp_seq=2 hlim=55 time=99.175 ms
16 bytes from 2a00:1450:8001::68, icmp_seq=3 hlim=55 time=98.197 ms
16 bytes from 2a00:1450:8001::68, icmp_seq=4 hlim=55 time=96.186 ms
traceroute6 to ipv6.l.google.com (2a00:1450:8001::63) from 2001:1418:100:2ed::2, 64 hops max, 12 byte packets
1 gw-750.trn-01.it.sixxs.net 53.167 ms 53.05 ms 55.006 ms
2 if-1-12.charleston.CBQ.TRN.ipv6.ITgate.net 53.591 ms 54.7 ms 53.664 ms
3 if-0-1.scooby-monster.core.TRN.ipv6.ITgate.net 54.078 ms 54.368 ms 54.106 ms
4 if-4-0.tango.core.MIL2.ipv6.ITgate.net 56.795 ms 56.457 ms 56.781 ms
5 2001:450:2002:56::1 57.492 ms 57.398 ms 57.285 ms
6 2001:4860:1:1:0:ddd:0:38 75.059 ms 75.172 ms 75.547 ms
7 2001:4860:1:1:0:ddd:0:38 108.289 ms 74.506 ms 75.063 ms
8 2001:4860::1:0:9f2 75.269 ms 75.342 ms 75.267 ms
9 2001:4860::1:0:87c 85.089 ms 132.185 ms 2001:4860::1:0:7fe 123.466 ms
10 2001:4860::1:0:4b3 94.655 ms 2001:4860::1:0:8 93.461 ms 2001:4860::1:0:4b3 118.763 ms
11 2001:4860::1:0:2a 96.838 ms 2001:4860::1:0:12 98.532 ms 2001:4860::1:0:2a 97.135 ms
12 2001:4860::34 97.131 ms 99.102 ms 2001:4860::35 100.448 ms
13 2001:4860:0:1::1d 108.182 ms 107.229 ms 109.062 ms
14 * * *
15 * * *
16 * * * [...]
+-------------------+
| Germany --> Italy |
+-------------------+
T22466 -> ittrn01 PoP (v4 and v6)
=====================
PING ittrn01.sixxs.net (213.254.12.34): 56 data bytes
64 bytes from 213.254.12.34: icmp_seq=0 ttl=49 time=51.579 ms
64 bytes from 213.254.12.34: icmp_seq=1 ttl=49 time=49.981 ms
64 bytes from 213.254.12.34: icmp_seq=2 ttl=49 time=49.588 ms
64 bytes from 213.254.12.34: icmp_seq=3 ttl=49 time=50.720 ms
64 bytes from 213.254.12.34: icmp_seq=4 ttl=49 time=50.620 ms
PING6(56=40+8+8 bytes) 2001:a60:f000:b9::2 --> 2001:1418:10:2::2
5 packets transmitted, 0 packets received, 100.0% packet loss
traceroute to ittrn01.sixxs.net (213.254.12.34), 64 hops max, 40 byte packets
1 ppp-default.m-online.net (82.135.16.28) 29.958 ms 30.508 ms 30.58 ms
2 ten1-4.r1.muc7.m-online.net (82.135.16.161) 29.458 ms 29.746 ms 27.915 ms
3 te1-3.r1.muc3.m-online.net (212.18.6.50) 30.202 ms 30.177 ms 29.862 ms
4 te1-3.r1.muc3.m-online.net (212.18.6.50) 29.429 ms 30.789 ms 29.840 ms
5 ge-0-3-0-zcr2.muc.cw.net (62.208.255.149) 29.780 ms 30.366 ms 29.709 ms
6 so-6-3-0-dcr2.fra.cw.net (195.2.2.25) 37.824 ms 66.261 ms 36.740 ms
7 xe-0-3-0-xcr1.fra.cw.net (195.2.9.241) 38.258 ms xe-11-3-0-xcr1.fra.cw.net (195.2.9.249) 37.568 ms 37.745 ms
8 sl-gw23-fra-1-0-0.sprintlink.net (217.147.97.93) 36.320 ms 36.459 ms 37.299 ms
9 sl-bb20-fra-9-0-0.sprintlink.net (217.147.96.67) 37.111 ms 36.590 ms 37.71 ms
10 sl-crs1-fra-0-0-0-0.sprintlink.net (217.147.96.74) 37.504 ms 36.738 ms 37.11 ms
11 sl-bb20-zur-11-0-0.sprintlink.net (213.206.129.125) 51.107 ms 41.141 ms 40.935 ms
12 sl-bb21-zur-15-0-0.sprintlink.net (80.93.8.43) 41.698 ms 40.968 ms 41.615 ms
13 sl-bb21-mil-4-0-0.sprintlink.net (213.206.129.127) 45.627 ms 45.676 ms 45.537 ms
14 217.147.128.41 (217.147.128.41) 45.711 ms 46.646 ms 46.397 ms
15 217.147.129.54 (217.147.129.54) 46.852 ms 46.703 ms 45.217 ms
16 if-0-3.scrappy-monster.core.TRN.itgate.net (213.254.31.245) 49.456 ms 50.169 ms 49.368 ms
17 if-0-0.charleston.CBQ.TRN.itgate.net (213.254.0.13) 48.423 ms 50.515 ms 50.736 ms
18 frejus.ITgate.net (213.254.12.34) 48.933 ms 49.693 ms 49.180 ms
traceroute6 to ittrn01.sixxs.net (2001:1418:10:2::2) from 2001:a60:f000:b9::2, 64 hops max, 12 byte packets
1 gw-186.muc-02.de.sixxs.net 29.511 ms 30.705 ms 30.099 ms
2 2001:a60:0:30::1 30.638 ms 30.643 ms 51.338 ms
3 ge-0-1-0-302-gar1.muc.cw.net 77.254 ms 78.445 ms 78.065 ms
4 * * *
5 * * *
6 * * *
7 if-0-0.charleston.CBQ.TRN.ipv6.ITgate.net 70.424 ms 69.762 ms 70.053 ms
8 * * *
9 * * *
10 * * *
11 * * * [...]
T22466 -> demuc02 PoP (v4 and v6)
=====================
PING demuc02.sixxs.net (62.245.150.2): 56 data bytes
64 bytes from 62.245.150.2: icmp_seq=0 ttl=61 time=29.804 ms
64 bytes from 62.245.150.2: icmp_seq=1 ttl=61 time=28.930 ms
64 bytes from 62.245.150.2: icmp_seq=2 ttl=61 time=28.587 ms
64 bytes from 62.245.150.2: icmp_seq=3 ttl=61 time=28.058 ms
64 bytes from 62.245.150.2: icmp_seq=4 ttl=61 time=28.895 ms
PING6(56=40+8+8 bytes) 2001:a60:f000:b9::2 --> 2001:a60:0:1:89:2:16:2
16 bytes from 2001:a60:0:1:89:2:16:2, icmp_seq=0 hlim=64 time=30.655 ms
16 bytes from 2001:a60:0:1:89:2:16:2, icmp_seq=1 hlim=64 time=29.073 ms
16 bytes from 2001:a60:0:1:89:2:16:2, icmp_seq=2 hlim=64 time=29.332 ms
16 bytes from 2001:a60:0:1:89:2:16:2, icmp_seq=3 hlim=64 time=28.812 ms
16 bytes from 2001:a60:0:1:89:2:16:2, icmp_seq=4 hlim=64 time=28.594 ms
traceroute to demuc02.sixxs.net (62.245.150.2), 64 hops max, 40 byte packets
1 ppp-default.m-online.net (82.135.16.28) 34.954 ms 30.214 ms 30.498 ms
2 ten1-4.r1.muc7.m-online.net (82.135.16.161) 29.27 ms 29.574 ms 29.425 ms
3 ten9-1.r1.muc2.m-online.net (212.18.7.153) 29.829 ms 30.310 ms 29.695 ms
4 demuc02.sixxs.net (62.245.150.2) 29.186 ms 28.582 ms 28.232 ms
traceroute6 to demuc02.sixxs.net (2001:a60:0:1:89:2:16:2) from 2001:a60:f000:b9::2, 64 hops max, 12 byte packets
1 2001:a60:0:1:89:2:16:2 29.746 ms 30.193 ms 30.07 ms
T22466 -> T21777 (v6 only)
================
PING6(56=40+8+8 bytes) 2001:a60:f000:b9::2 --> 2001:1418:100:2ed::2
5 packets transmitted, 0 packets received, 100.0% packet loss
traceroute6 to neu-sorpigal.aleturo.com (2001:1418:100:2ed::2) from 2001:a60:f000:b9::2, 64 hops max, 12 byte packets
1 gw-186.muc-02.de.sixxs.net 30.109 ms 30.772 ms 29.877 ms
2 2001:a60:0:30::1 31.189 ms 31.025 ms 30.64 ms
3 ge-0-1-0-302-gar1.muc.cw.net 77.91 ms 78.188 ms 77.596 ms
4 * * *
5 * * *
6 * * *
7 if-0-0.charleston.CBQ.TRN.ipv6.ITgate.net 71.719 ms 70.355 ms 70.537 ms
8 * * *
9 * * *
10 * * *
11 * * * [...]
T22466 -> noc.sixxs.net (v6 only)
=======================
PING6(56=40+8+8 bytes) 2001:a60:f000:b9::2 --> 2001:838:1:1:210:dcff:fe20:7c7c
16 bytes from 2001:838:1:1:210:dcff:fe20:7c7c, icmp_seq=0 hlim=56 time=63.535 ms
16 bytes from 2001:838:1:1:210:dcff:fe20:7c7c, icmp_seq=1 hlim=56 time=62.054 ms
16 bytes from 2001:838:1:1:210:dcff:fe20:7c7c, icmp_seq=2 hlim=56 time=61.529 ms
16 bytes from 2001:838:1:1:210:dcff:fe20:7c7c, icmp_seq=3 hlim=56 time=62.056 ms
16 bytes from 2001:838:1:1:210:dcff:fe20:7c7c, icmp_seq=4 hlim=56 time=61.634 ms
traceroute6 to noc.sixxs.net (2001:838:1:1:210:dcff:fe20:7c7c) from 2001:a60:f000:b9::2, 64 hops max, 12 byte packets
1 gw-186.muc-02.de.sixxs.net 30.027 ms 30.531 ms 30.082 ms
2 2001:a60:0:30::1 29.736 ms 30.473 ms 30.427 ms
3 2001:6f8:1:0:87:86:77:248 42.723 ms 596.753 ms 39.514 ms
4 2001:6f8:1:0:87:86:77:63 587.995 ms 222.489 ms 47.045 ms
5 2001:6f8:1:0:87:82:50:236 61.329 ms 61.174 ms 61.771 ms
6 2001:838:5:a::2 63.413 ms 63.047 ms 62.967 ms
7 noc.sixxs.net 63.774 ms 62.866 ms 63.531 ms
T22466 -> ipv6.google.com (v6 only)
=========================
PING6(56=40+8+8 bytes) 2001:a60:f000:b9::2 --> 2a00:1450:8001::93
16 bytes from 2a00:1450:8001::93, icmp_seq=0 hlim=55 time=49.655 ms
16 bytes from 2a00:1450:8001::93, icmp_seq=1 hlim=55 time=47.714 ms
16 bytes from 2a00:1450:8001::93, icmp_seq=2 hlim=55 time=47.895 ms
16 bytes from 2a00:1450:8001::93, icmp_seq=3 hlim=55 time=48.473 ms
16 bytes from 2a00:1450:8001::93, icmp_seq=4 hlim=55 time=48.323 ms
traceroute6 to ipv6.l.google.com (2a00:1450:8001::69) from 2001:a60:f000:b9::2, 64 hops max, 12 byte packets
1 gw-186.muc-02.de.sixxs.net 30.624 ms 29.912 ms 29.259 ms
2 2001:a60:0:30::1 30.545 ms 30.999 ms 30.531 ms
3 2001:4860::1:0:1f 31.378 ms 2001:4860::1:0:1e 31.335 ms 2001:4860::1:0:1f 31.143 ms
4 2001:4860::1:0:10 38.393 ms 2001:4860::1:0:11 44.635 ms 2001:4860::1:0:10 57.997 ms
5 2001:4860::1:0:4b3 125.345 ms 144.934 ms 2001:4860::1:0:8 41.979 ms
6 2001:4860::1:0:12 48.135 ms 2001:4860::1:0:2a 48.565 ms 48.107 ms
7 2001:4860::35 52.308 ms 47.451 ms 49.649 ms
8 2001:4860:0:1::1d 59.082 ms 55.677 ms 53.373 ms
9 * * *
10 * * *
11 * * * [...]
State change: user
The state of this ticket has been changed to user
Routing problems between demuc02 and ittrn01
Fix your MTU.
Routing problems between demuc02 and ittrn01
Shadow Hawkins on Sunday, 04 April 2010 00:12:17
Hello!
The MTUs on both tunnel endpoints are the default 1280 as preset by AICCU (as I always let the tunnels be set up by it). The settings of the IPv4 layer haven't been changed for considerable time now (at least several months), and it has been working flawlessly before.
Well, to be precise, T21777 has been moved from heartbeat to static a few days ago (moving from a PPPoE to a RFC1483 bridged connection on that occasion), but the problem has appeared a few days prior to that -- so this particular switch cannot be the cause.
I did try to set up MSS clamping in order to rule out MTU issues, but that didn't change anything. Tinkering with the MTU settings didn't change anything, too. But shouldn't it be that a wrong MTU only affects bigger packets, i.e. especially _not_ things that are as small as little ping probes? Or am I missing another detail?
Stefan
Routing problems between demuc02 and ittrn01
Shadow Hawkins on Sunday, 04 April 2010 00:25:54
Hello!
I've been trying to have tcpdump listen what's happening between the tunnel endpoint and the PoP on both sides. I noticed that whenever the T21777 endpoint (which hangs on the ittrn01 PoP) trys to initiate any kind of connection with T22466, of course all the handshakes and such go on, but there is also a considerable amount of ICMP error packets (unreachable route) which are sent back to T21777. But those do not originate from either PoP, nor from any of my hosts, but from one of the hops that lie along the route from T21777 to T22466:
This is one of the errors as captured by tcpdump:
| 2001:668:0:2::1:16d2 > 2001:1418:100:2ed::2: icmp6: 2001:a60:f000:b9::2 unreachable route (encap)
This is consistent with the last line of the traceroute6 output:
8 xe-1-1-0.fra23.ip.tinet.net 105.178 ms !N 68.146 ms !N 67.731 ms !N
I get the same ICMP errors when the german host tries to connect to the italian one, e.g. doing pings or zone transfers: I see the (IPv6) connection attempts, then the reply is sent, then an the beforementioned ICMP error is sent right back, always coming from 2001:668:0:2::1:16d2.
Is it possible that 2001:668:0:2::1:16d2 is actually the problem, and that the connections that _do_ come through are just pure coincidence as they get routed another way?
Regards, Stefan
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on Saturday, 03 April 2010 19:56:09
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