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North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: Recommendation of Tools
On Wed, 3 Dec 2008, Anders Lindbäck wrote: 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.. No, it doesn't try pinging the routers in the middle, at least not anymore (I just re-checked with 0.71 and 0.75). I vaguely recall behaviour like that in the past, however, so it's possible that long time ago mtr did behave that way. 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.. This is true and the point I was getting at, though I believe the bucket is much larger in any recent software release (also in 12.0 series). Actually, 5 years ago, you could see spot Cisco routers in "traceroute6" because they dropped the rate-limiter didn't respond to the middle packet and it resulted in a star. The rate-limiter has long since been fixed to be more lenient. -- Pekka Savola "You each name yourselves king, yet the Netcore Oy kingdom bleeds." Systems. Networks. Security. -- George R.R. Martin: A Clash of Kings
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