traceroute6 not working?
Shadow Hawkins on Tuesday, 08 February 2005 00:16:34
Hi, I try to traceroute6 to multiple servers and almost never get an answer or just a few hops. I just want to ask if that is normal behavior. I connect via the BIT BV PoP.
Example:
alita:~# ping6 -n irc.uni-erlangen.de
PING irc.uni-erlangen.de(2001:638:a00:2::53) from 2001:7b8:38e::abcd : 56 data bytes
64 bytes from 2001:638:a00:2::53: icmp_seq=1 ttl=242 time=60.0 ms
64 bytes from 2001:638:a00:2::53: icmp_seq=2 ttl=242 time=58.9 ms
64 bytes from 2001:638:a00:2::53: icmp_seq=3 ttl=242 time=58.9 ms
traceroute to ircserver.rrze.uni-erlangen.de (2001:638:a00:2::53) from 2001:7b8:38e::abcd, 30 hops max, 16 byte packets
1 * * *
2 * * *
3 * * *
4 * * *
5 * * *
6 * * *
7 * * *
8 * * *
9 2001:5000:0:5::2 (2001:5000:0:5::2) 38.912 ms 38.836 ms 39.082 ms
10 2001:5000:0:2::2 (2001:5000:0:2::2) 39.286 ms 40.609 ms 38.663 ms
11 2001:5001:100:6::2 (2001:5001:100:6::2) 45.508 ms 45.965 ms 45.704 ms
12 nr-erl1.6win.dfn.de (2001:638:f:a00::2:1) 57.55 ms 58.126 ms 57.809 ms
13 n2uni-erl.nr-erl1.6win.dfn.de (2001:638:0:a00::a00:2) 54.544 ms 55.587 ms 55.633 ms
14 * * *
15 * * *
16 * * *
17 * * *
18 * * *
19 * * *
20 * * *
21 * * *
22 * * *
24 * * *
25 * * *
26 * * *
27 * * *
28 * * *
29 * * *
30 * * *
alita:~# ip addr show sixxs0
4: sixxs0@NONE: <POINTOPOINT,NOARP,UP> mtu 1280 qdisc noqueue
link/sit 0.0.0.0 peer 193.109.122.244
inet6 2001:7b8:2ff:113::2/64 scope global
inet6 2001:7b8:38e::1/128 scope global
inet6 2001:7b8:38e::abcd/128 scope global
inet6 2001:7b8:38e::dead:beef/128 scope global
inet6 2001:7b8:38e::ffff/128 scope global
inet6 fe80::d5ef:ced1/64 scope link
alita:~# ip -6 route show
2001:7b8:2ff:113::/64 via :: dev sixxs0 metric 256 mtu 1280 advmss 1220
2001:7b8:38e::/48 dev sixxs0 metric 1024 mtu 1280 advmss 1220
fe80::/64 dev eth0 metric 256 mtu 1500 advmss 1220
fe80::/64 via :: dev sixxs0 metric 256 mtu 1280 advmss 1220
ff00::/8 dev eth0 metric 256 mtu 1500 advmss 1220
ff00::/8 dev sixxs0 metric 256 mtu 1280 advmss 1220
default via 2001:7b8:2ff:113::1 dev sixxs0 metric 1024 mtu 1280 advmss 1220
Regards,
Sebastian
traceroute6 not working?
Jeroen Massar on Tuesday, 08 February 2005 09:29:39
Do a "ip link sho", this will reveal that your TTL is set wrongly.
How to configure Linux contains the following:
Fix MTU and TTL
# ip link set mtu 1280 dev sixxs
# ip tunnel change sixxs ttl 64
The reason for this being that it otherwise the tunnel interface uses a TTL of 1 which does not work as you just demonstrated.
traceroute6 not working?
Shadow Hawkins on Tuesday, 08 February 2005 11:12:53
Oh that explains it. I only used the debian config FAQ:
https://noc.sixxs.net/faq/connectivity/?faq=ossetup&os=linuxdebian
Please change
up ip link set mtu 1280 dev sixxs
up ip route add default via [POP IPv6 Endpoint] dev sixxs
to
up ip link set mtu 1280 dev sixxs
up ip tunnel change sixxs ttl 64
up ip route add default via [POP IPv6 Endpoint] dev sixxs
on that page.
traceroute6 not working?
Jeroen Massar on Tuesday, 08 February 2005 11:38:09
8<---------
Put in /etc/network/interfaces:
auto sixxs
iface sixxs inet6 v4tunnel
address [Your IPv6 Endpoint]
netmask [Prefix Length]
endpoint [POP IPv4 Endpoint]
ttl 64
up ip link set mtu 1280 dev sixxs
up ip route add default via [POP IPv6 Endpoint] dev sixxs
----------->8
It already contains the 'ttl 64' line there which is handled by the debian configuration setup, I am quite sure as that is what I have been using all the time ;)
traceroute6 not working?
Shadow Hawkins on Tuesday, 08 February 2005 12:16:10
Sorry I can't confirm this:
I restarted my interface without the ip tunnel change line:
----------------
auto sixxs0
iface sixxs0 inet6 v4tunnel
address 2001:7b8:2ff:113::2
netmask 64
endpoint 193.109.122.244
ttl 64
up ip link set mtu 1280 dev sixxs0
#up ip tunnel change sixxs0 ttl 64
up ip -6 route add default via 2001:7b8:2ff:113::1 dev sixxs0
up ip -6 route add 2001:7b8:38e::/48 dev sixxs0
up ip -6 addr add 2001:7b8:38e::abcd dev sixxs0
----------------
alita:~# ip link show sixxs0
6: sixxs0@NONE: <POINTOPOINT,NOARP,UP> mtu 1280 qdisc noqueue
link/sit 0.0.0.0 peer 193.109.122.244
alita:~# ip tunnel show sixxs0
sixxs0: ipv6/ip remote 193.109.122.244 local any ttl inherit
alita:~# traceroute6 irc.uni-erlangen.de
traceroute to ircserver.rrze.uni-erlangen.de (2001:638:a00:2::53) from 2001:7b8:38e::abcd, 30 hops max, 16 byte packets
1 * * *
2 * * *
3 * * *
alita:~# ip tunnel change sixxs0 ttl 64
alita:~# ip link show sixxs0
6: sixxs0@NONE: <POINTOPOINT,NOARP,UP> mtu 1280 qdisc noqueue
link/sit 0.0.0.0 peer 193.109.122.244
alita:~# ip tunnel show sixxs0
sixxs0: ipv6/ip remote 193.109.122.244 local any ttl 64
alita:~# traceroute6 irc.uni-erlangen.de
traceroute to ircserver.rrze.uni-erlangen.de (2001:638:a00:2::53) from 2001:7b8:38e::abcd, 30 hops max, 16 byte packets
1 gw-276.ede-01.nl.sixxs.net (2001:7b8:2ff:113::1) 17.207 ms 15.453 ms 15.914 ms
2 sixxs-gw.ipv6.network.bit.nl (2001:7b8:3:4f:290:6900:4fc6:d81f) 14.399 ms 15.325 ms 15.451 ms
3 jun1.telecity.ipv6.network.bit.nl (2001:7b8::290:6900:1c6:7c1f) 15.566 ms 16.055 ms 16.426 ms
4 zpr2.amt.cw.net (2001:7f8:1::a500:1273:1) 16.527 ms 15.576 ms 16.113 ms
alita:~# uname -a
Linux alita 2.4.29 #1 Sat Jan 22 01:34:41 CET 2005 i686 unknown
I think that perhaps the ttl keyword is only valid in newer debian releases (with newer ifup/ifdown versions)
traceroute6 not working?
Jeroen Massar on Tuesday, 08 February 2005 12:34:14 I think that perhaps the ttl keyword is only valid in newer debian releases (with newer ifup/ifdown versions)
If you are doing IPv6 you are likely to be needing all the new tools anyway, thus run unstable....
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