[ale] [OT] ping

[Mike Harrison]

On Mon, 19 Jul 2010, Paul Cartwright wrote:

> On Mon July 19 2010, Michael B. Trausch wrote:
>> I _love_ mtr, however "ping -c4 hostname.example.org" is so ingrained in
>> my "muscle memory"---and it does the job that I need 99% of the
>> time---that I still just use it as a matter of reflex.
>
> what is this telling me?
> mtr dyndns.org
>
> gi1-48.3802.mpd01.atl04.atlas.cogentco.com     	15% 	 56	66
> te7-4.mpd02.atl01.atlas.cogentco.com 		22%  	51	66
> 38.104.190.54					73%	17	66
> dyndns.org           			     	 70%	 19	66

That 38.104.190.54 is PROBABLY (but not necessarily) the cause of some
serious packet loss. As it is on an old PSI IP address range and connected
by Cogent, it's a pretty fair possibility. It could also be mostly the 
dyndns.org server itself and 38.104.190.54 is suffering under load of all 
the dropped packets and traffic. In my trace below, I'll wager that the 
high times of ..186.29 cause the loss on .186.18

MTR is a tool, not a diagnosis and often routers will drop packets
for many reasons.

$ mtr --report -c 3 dyndns.org
HOST: gemini                      Loss%   Snt   Last   Avg  Best  Wrst StDev
   1. gw.utiliflex.com              0.0%     3    0.2   0.2   0.2   0.3   0.1
   2. static-host-74-205-136-1.epb  0.0%     3    5.7   7.2   5.7   8.8   1.5
   3. ???                          100.0     3    0.0   0.0   0.0   0.0   0.0
   4. ???                          100.0     3    0.0   0.0   0.0   0.0   0.0
   5. 12.91.215.185                 0.0%     3    5.9   5.3   4.4   5.9   0.8
   6. cr81.atnga.ip.att.net         0.0%     3    6.9  33.4   6.9  83.3  43.2
   7. cr2.attga.ip.att.net          0.0%     3   11.7   9.7   6.8  11.7   2.6
   8. attga01jt.ip.att.net          0.0%     3    8.2   7.5   4.4  10.0   2.9
   9. 192.205.36.202                0.0%     3   17.6  13.1   6.0  17.6   6.2
  10. if-7-0-0-60.har1.A56-Atlanta  0.0%     3   10.2   9.8   9.0  10.2   0.7
  11. if-11-0-0.core3.AEQ-Ashburn.  0.0%     3   22.1  22.2  20.6  23.8   1.6
  12. 63.243.186.29                 0.0%     3  102.8  66.2  32.7 102.8  35.1
  13. 63.243.186.18                66.7%     3   49.1  49.1  49.1  49.1   0.0
  14. Vlan572.icore1.NTO-NewYork.a  0.0%     3   28.8  28.0  25.6  29.5   2.1
  15. dyndns.org                    0.0%     3   25.3  25.0  24.8  25.3   0.2