traceroute times out

centr0 · 04-21-2004, 10:53 PM

im basically having trouble tracerouting any host. it seems to get stuck at launchmodem? i thought it was the router but i could not see anything that blocked ICMP packets. any help would be appreciated. thanks. heres the output

Code:

 1  192.168.0.1 (192.168.0.1)  0.182 ms  0.181 ms  0.139 ms
 2  launchmodem (192.168.1.254)  0.785 ms  0.747 ms  0.770 ms
 3  launchmodem (192.168.1.254)  0.725 ms  0.758 ms  0.729 ms
 4   *

chort · 04-22-2004, 03:06 AM

UNIX (really, BSD derived IIRC) traceroute doesn't use ICMP outgoing, it uses UDP on high ports to generate a response that is ICMP PORT UNREACHABLE. It looks like the TCP/IP (er... IP, really) stack on your router is incorrectly forwarding packets with a 0 ttl, which is why you get two responses from the same IP. As to why nothing after the modem responds... who knows? Maybe it's blocking return ICMP error codes... did you try letting the traceroute run for a minute or two and see if it eventually gets a response from a host further down the line?

maxut · 04-22-2004, 03:08 AM

i guess it still blocks icmp. can u ping external interface of your launchmodem?

centr0 · 04-22-2004, 03:47 AM

chort: no i dont get a response down the line. its all "*". as far as forwarding packets, i wouldnt know anything about that. i logged into the router and i didnt see anything there that pertains to dropping ICMP error codes.

maxut: ping is ICMP is that correct? ping yahoo.com works. traceroute doesnt.

maxut · 04-22-2004, 04:42 AM

ping is an ICMP type packet. as i remeber it is ICMP type 8 -10 . i didnt mean ping yahoo.com works. i asked u can ping ppp interface of modem.

but chort know much more than i know.