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For example, if I run this command against example.com, with mtr command, I always get 10% of loss, no matter how many time I run, why exactly is 10%?

mtr --report 192.0.43.10
HOST: localhost Loss%   Snt   Last   Avg  Best  Wrst StDev
  1.|-- ip-10-28-120-1.eu-west-1.  0.0%    10    0.5   1.8   0.4  11.4   3.4
  2.|-- ip-10-5-34-126.eu-west-1.  0.0%    10    0.4   2.5   0.4   8.9   2.9
  3.|-- 100.64.12.4                0.0%    10    0.5   0.6   0.4   0.7   0.1
  4.|-- 100.64.12.11               0.0%    10    0.5   0.6   0.4   0.9   0.1
  5.|-- ec2-79-125-1-98.eu-west-1  0.0%    10    0.8   0.7   0.6   0.8   0.1
  6.|-- 178.236.1.4                0.0%    10    0.8   0.8   0.6   0.9   0.1
  7.|-- 178.236.0.138              0.0%    10    1.3   1.4   1.3   1.6   0.1
  8.|-- 178.236.0.121              0.0%    10    1.4   1.7   1.3   4.2   0.9
  9.|-- 213.242.106.85             0.0%    10    1.7   1.6   1.4   1.8   0.1
 10.|-- ae-1-4.bar1.Dublin3.Level  0.0%    10    2.3   2.4   2.3   2.6   0.1
 11.|-- ae-12-12.ebr2.Paris1.Leve  0.0%    10   96.0  96.2  95.9  97.5   0.5
 12.|-- ae-42-42.ebr2.Washington1  0.0%    10   97.4  97.2  97.0  97.5   0.2
 13.|-- ae-62-62.csw1.Washington1  0.0%    10   98.3  99.3  98.1 104.0   2.0
 14.|-- ae-1-60.edge1.Washington1  0.0%    10   95.8 103.2  95.7 158.6  19.8
 15.|-- INTERNET-CO.edge1.Washing  0.0%    10  101.5 101.5 101.4 101.8   0.1
 16.|-- 43-10.any.icann.org       10.0%    10   99.1 102.1  98.2 107.2   3.8
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2 Answers 2

up vote 4 down vote accepted

The 43-10.any.icann.org may have the priority for ICMP echo requests used by mtr lowered. The mtr tools is not 100% reliable to measure packet losses. Try using the iperf tool instead that can use UDP datagrams instead of ICMP echo requests to measure packet loss.

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mtr also has option (-u) to use UDP datagrams instead of ICMP echo requests –  fpmurphy1 Feb 28 '13 at 15:08

There's actually a bug in mtr for report mode that mis counts the last packet. It's fixed in a newer version (mtr v0.80)

See: https://bugs.launchpad.net/ubuntu/+source/mtr/+bug/966065 https://bugzilla.redhat.com/show_bug.cgi?id=611739

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Ten packets, one lost, 10% loss. –  David Schwartz Mar 28 at 22:06

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