Odd cableone traceroute with 0.0.0.0 in path

Thu Oct 28 18:55:56 UTC 2010

Okay, so this has my head hurting a bit just trying to figure out just 
how this is possible and what kind of equipment would pull this stunt.

Tracing from here (cableone cable modem) to the outside world, I end up 
with the following at the beginning of my traceroute.

  1  192.168.1.1 (192.168.1.1)  2.759 ms  0.803 ms  0.769 ms
  2  0.0.0.0 (0.0.0.0)  10.462 ms  9.543 ms  8.043 ms
  3  192.168.32.65 (192.168.32.65)  9.984 ms  9.654 ms  9.570 ms
  4  te-4-4.car2.seattle1.level3.net (4.53.146.117)  25.960 ms  21.798 
ms  24.144 ms
....  etc

0.0.0.0 as one of the hops.    So, I pulled out LFT to make sure 
traceroute isn't going nuts.

Layer Four Traceroute (LFT) version 3.1
Using device en1, 192.168.1.101:53
TTL LFT trace to 207.70.17.213:80/tcp
  1  192.168.1.1 0.9/0.9ms
  2 /9.8/10.3ms
  3  192.168.32.65 9.7/8.3ms
  4  10.255.255.1 9.1/8.4ms
  5  te-4-4.car2.seattle1.level3.net (4.53.146.117) 29.0/20.2ms

Fun, no entry for hop 2, plus there's an extra hop at #4.  Lets use verbose.

Layer Four Traceroute (LFT) version 3.1 ... (verbosity level 2)
Using device en1, 192.168.1.101:53
SENT TCP  TTL=1 SEQ=648736948 FLAGS=0x2 ( SYN )
SENT TCP  TTL=2 SEQ=648736949 FLAGS=0x2 ( SYN )
RCVD ICMP SEQ=648736948 SRC=192.168.1.1 PTTL=1 PSEQ=648736948
SENT TCP  TTL=3 SEQ=648736950 FLAGS=0x2 ( SYN )
SENT TCP  TTL=4 SEQ=648736951 FLAGS=0x2 ( SYN )
SENT TCP  TTL=5 SEQ=648736952 FLAGS=0x2 ( SYN )
SENT TCP  TTL=6 SEQ=648736953 FLAGS=0x2 ( SYN )
RCVD ICMP SEQ=648736949 SRC=0.0.0.0 PTTL=2 PSEQ=648736949
SENT TCP  TTL=7 SEQ=648736954 FLAGS=0x2 ( SYN )
RCVD ICMP SEQ=648736950 SRC=192.168.32.65 PTTL=3 PSEQ=648736950
RCVD ICMP SEQ=648736951 SRC=10.255.255.1 PTTL=4 PSEQ=648736951
RCVD ICMP SEQ=648736953 SRC=4.68.105.30 PTTL=6 PSEQ=648736953

Am I going nuts, or is something really messed up somewhere upstream 
from the cable modem?  To quote someone from IRC who's just as confused, 
"the null route just talked to me".

-- 
Brielle Bruns
The Summit Open Source Development Group
http://www.sosdg.org    /     http://www.ahbl.org