IPv6: traceroute/UDP problem

Chang-hao Tsai (chtsai@ccstudent.ee.ntu.edu.tw)
Tue, 19 Aug 1997 15:11:58 +0800 (CST)


Hello, all

I'm sorry to bother you. This problem confused me
these days. I'm testing traceroute1.4a4+ipv6-2 on my
linux (kernel 2.1.49). When I issue the following
traceroute command, I got wired result:

v6host2:~# traceroute -q 10 v6test1
traceroute to v6test1 (5f06:7b00:8c70:1300:0:80:c81a:9c3),
30 hops max, 60 byte packets
1 v6test1 (5f06:7b00:8c70:1300:0:80:c81a:9c3) 1.801 ms *
1.772 ms * 1.776 ms * 1.681 ms * 1.720 ms *

It seems that it lost every other packet. But when
I used sniffer to catch the packets on the Ethernet
directly, I found that traceroute even didn't send the
UDP probe packet. traceroute just send half number of
UDP probe packets but wait for all ICMP packets back.
I changed to use ICMP echo instead of UDP probe packets
and everything is okay. For example,

v6host2:~# traceroute -I -q 10 v6test1
traceroute to v6test1 (5f06:7b00:8c70:1300:0:80:c81a:9c3),
30 hops max, 60 byte packets
1 v6test1 (5f06:7b00:8c70:1300:0:80:c81a:9c3) 3.535 ms ! 1.480 ms
1.354 ms 4.125 ms 6.450 ms 2.348 ms 1.865 ms 1.346 ms
2.395 ms 1.844 ms

Is there anybody help me to solve this?

-- 
Howard Chang-hao Tsai
Nat.Taiwan Univ. Dept. E.E. Highspeed Network Lab.
chtsai@cctwin.ee.ntu.edu.tw