[luau] Strange find....

[MonMotha]

Ben Beeson wrote:
> Monmotha,
> 
> 	Thanks for the info.   
> 
>>Well, there's the imfamouns 10.x.x.x one, which I do believe is your cable
>>modem (which oddly enough, acts as a bridge, but still decrements the TTL
>>and sends back a time exceeded as if it were a router...)   
> 
> 
> You're probably right here, the 10.x.x.x IP address is the next one after the 
> linux router, but I'm now curious about the bridge thing.  I thought bridges 
> were supposed to be transparent.  Does this result imply that the cablemodem 
> is dual-homed on a single interface?

The impression I got was that it's just a misconfigured bridge :)  Since it's 
the first hop after your box, and you are using the actual upstream (here it's a 
24.x.x.x address, the first IP in our subnet), you aren't actually sending 
packets to the device at all, so it shouldn't respond with a TTL exceeded (and 
shouldn't decrement TTL) as if it were a router (because you're not takling to 
it as a rotuer, and in fact you are in the same IP subnet as the ISP's router). 
  I have no confirmation, but I gather this is the actual IP address the cable 
modem provider uses for configuration of the device.  Telnetting to it gives a 
rather scary "don't use this" disclaimer, thoguh if you own your cable modem 
(rather than lease it like I do), this MAY not apply (IANAL!).  I haven't 
checked, but I wouldn't be surprised if it speaks SNMP.

> 
> Other than
> 
>>that, nothing I've found hasn't been visible from a simple traceroute.
>>
> 
> 
> 	Well, when I tracerouted the IPADDR, it doesn't get all the way to the 
> IPADDR I look for. But when I ping it, or telnet to it, I find the spot I'm 
> looking for -- it is there. 

That's not uncommon.  You're probably going through a firewall that either 
blocks incoming UDP packets to really high ports (that's how traceroute works) 
or blocks outbound TTL exceeded packets (which means the firewall is stupid).

--MonMotha