Subject: ipv6 icmps TTL EIT from bad interface ?
To: None <current-users@netbsd.org>
From: Mihai CHELARU <kefren@netbsd.ro>
List: current-users
Date: 09/03/2005 19:26:49
Hello,

I'm having the following setup:

Router 1:
 tlp0 (inet6 2001:618:423::2 prefixlen 64),
 gif1 (inet6 2001:618:423:beef::5 ->  prefixlen 126)

Router 2:
 gif0(inet6 2001:618:423:beef::6 ->  prefixlen 126)
 ex0(inet6 2001:618:423:bad::1 prefixlen 64)

Host 1:
 stge0(inet6 2001:618:423:bad:250:8dff:fed1:cc04 prefixlen 64)

Router 1 is the border router in this case.

Packets from Router2 to internet should go Router1 then to Internet. 
Packets from Host1 should go Router2, Router 1, Internet.

Ok, let's test with traceroute6:

Router2:
1  2001:618:423:beef::5  3.823 ms  3.149 ms  3.473 ms
 2  2001:618:423::1  3.542 ms  4.892 ms  4.74 ms
 3  2001:618:423:beef::1  4.921 ms  5.086 ms  6.348 ms
 4  2001:618:400::1  83.328 ms  86.773 ms  84.022 ms
....

Host1:
 1  2001:618:423:bad::1  0.331 ms  0.278 ms  0.278 ms
 2  2001:618:423::2  3.904 ms  3.535 ms  3.99 ms
 3  2001:618:423::1  3.911 ms  6.002 ms  4.215 ms
 4  2001:618:423:beef::1  4.928 ms  4.55 ms  6.168 ms
 5  2001:618:400::1  83.011 ms  83.561 ms  86.979 ms

Compare Router2 traceroute's hop1 with Host1 traceroute's hop2. Why is 
Router1 responding with the tlp0 interface address in the second case 
instead of gif0 address ? How makes it respondes ok in the first case ?

Router1 is 3.0 BETA, Router 2 is 2.0 BETA and Host1 is 3.99.5.

-- 
thanks,
Mihai