[hobbit] Re: Conn test problems

Hobbit User in Richmond hobbit at epperson.homelinux.net
Mon Jan 14 19:02:34 CET 2008


Presumably.

On Mon, January 14, 2008 12:40, Josh Luthman wrote:
> Wouldn't the traceroute used by Hobbit be the same command as the shell?
>
> On 1/14/08, Hobbit User in Richmond <hobbit at epperson.homelinux.net>
> wrote:
>>
>> Actually, ICMP echo-request and echo-reply packets are almost certainly
>>  not an issue here, nor is packet-filtering/firewalling.  In current
>> implementations, traceroute by default uses UDP packets to abitrary and
>>  unlikely-to-respond ports, varying the TTL and using the ICMP type 11
>> (Time Exceeded) from hops along the way to map the routing path.
>>
>> The manpage in Fedora 8 says "We start our probes with a ttl of one and
>>  increase by one until we...got to the "host", or hit a max (which
>> defaults to  30  hops)".
>>
>> So, the behavior you're seeing is as documented.  If a firewall were an
>>  issue in sending/receiving the packets used by traceroute, you'd see
>> the 30-hop behavior whether the host was up or down.
>>
>> On Mon, January 14, 2008 11:17, Michael A. Price wrote:
>>> Josh,
>>>
>>>
>>>
>>> Thanks for helping... The source/destination is on a closed network,
>>> sorry...and I don't own the router...
>>>
>>>
>>>
>>> But, I don't understand, how the traceroute works when the host is
>>> up, but when the host is down it times out???
>>>
>>>
>>>
>>> If it works when the host is up, then you would think the ACL on the
>>> router just before the host would allow my ICMP packets through.
>>>
>>>
>>>
>>> What is your thoughts???



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