Recommendation of Tools

Wed Dec 3 18:01:37 UTC 2008

Mtr is even less usefull then that, in its default mode it does a  
traceroute and then proceeds to ICMP Ping flood each IP in the list  
generated by the traceroute, the result is usually completly useless  
on WAN topologies due to asym-routing, ICMP node protections by  
carriers and punting etc..

And using UDP will not really provide better results due to the same  
thing, and IIRC Cisco from 12.0 has a standard setting of no more  
then 1 ICMP Unreach per 500ms..

------------------------------
Anders Lindbäck
anders.lindback at dnz.se

On 3 dec 2008, at 12.00, Pekka Savola wrote:

> On Tue, 2 Dec 2008, Antonio Querubin wrote:
>> On Wed, 3 Dec 2008, Pekka Savola wrote:
>>>  FWIW, Mtr measures latency/delay and loss based on ICMP messages  
>>> heard
>>>  back from the routers on path.  As a result, in almost all  
>>> cases, the real
>>>  hop-by-hop latency of actual end-to-end data packets is better  
>>> than it can
>>>  report.
>>
>> mtr has a recently added '-u' option to use UDP instead of ICMP  
>> echo requests.
>
> But that doesn't change the gist of my message: it's still relying  
> on ICMP ttl exceeded messages sent by the routers on the path to  
> check the delays etc.  As such it suffers from basically the same  
> limitations as ICMP probing.
>
> -- 
> Pekka Savola                 "You each name yourselves king, yet the
> Netcore Oy                    kingdom bleeds."
> Systems. Networks. Security. -- George R.R. Martin: A Clash of Kings
>