ICMP TTL bug?

[ispark]

Hello all.

I recently noticed this when I do a trace to my IP using VisualRoute trace route program. This was done with the program on my machine and from the VisualRoute server (live demo) at their site

The TCP/IP stack on '66.xxx.xxx.xxx' appears to have a bug. It uses the incoming TTL as the outgoing TTL of an ICMP packet.

My question is,
should I even worry with this problem? and if I should, how is it fixed?

Thanks

[ispark]

any idea's at all?

[Kip Patterson]

Originally posted by ispark
Hello all.


The TCP/IP stack on '66.xxx.xxx.xxx' appears to have a bug. It uses the incoming TTL as the outgoing TTL of an ICMP packet.

Thanks

what is "66.xx.xx.xx"? Your computer? Please post a trace route and we'll have a look.

Kip

[ispark]

===================================================
=== VisualRoute report on 11-Dec-02 6:32:47 AM ===
===================================================

Report for 66.xxx.xxx.xxx - my cable modem IP

Analysis: Node '66.xxx.xxx.xxx' was found in 1 hops (TTL=1). The TCP/IP stack on '66.xxx.xxx.xxx' appears to have a bug. It uses the incoming
TTL as the outgoing TTL of an ICMP packet. Connections to HTTP port 80 are being rejected.

--------------------------------------------------------------------------------------------------------------------------
| Hop | % Loss | IP Address | Node Name | Location | Timezone | ms | Graph | Network |
--------------------------------------------------------------------------------------------------------------------------
| 0 | | 192.168.0.2 | iSpark.sccoast.net | ... | | | | (private use) |
| 1 | | 66.xxx.xxx.xxx | 162.179-serial-fratm-mi.sccoast.net | | | 0 | | 66.xxx.xxx.x |
--------------------------------------------------------------------------------------------------------------------------
VisualRoute Report for 66.xxx.xxx.xxx produced at 6:32 AM on December 11, 2002.
Roundtrip time to 66.xxx.xxx.xxx (66.xxx.xxx.xxx) average = 0ms min = 0ms max = 0ms

[Kip Patterson]

The 66.x.x.x IP is the address of your computer, so VisualRoute is essentially pinging the computer it is running on. I don't know why you get that result, but you can safely ignore it so far as I can see.

Kip

[ispark]

Actually, 66.xxx.xxx.xxx is the IP of my cable modem which is hooked up to my netgear router.

I was just curious if that message from VR was worth worrying about.

Thanks.

[Kip Patterson]

Cable modems are bridges. They don't hve IP addresses except for diagnostic and support purposes. In your case, the 66.x.x.x address is the address of your router, assigned to it via DHCP.

Kip