mtr to diagnose network issues

[ruebenramirez]

mtr = my traceroute

combines ICMP based traceroute and pings into a single live stream view + report output command line tool.

I learned about MTR when I was experiencing a noisy neighbor issue with my linode VM and needed to rule out networking and machine other resource issues.

Example mtr run from the coffee shop I'm hacking from today:

$ sudo mtr -wbzc10 github.com
Start: Sat Mar  4 15:24:43 2017
HOST: macbookpro.local                                                  Loss%   Snt   Last   Avg  Best  Wrst StDev
  1. AS3215   2.2.2.3                                                    0.0%    10  130.0  69.4  39.0 130.0  35.1
  2. AS3549   207-71-33-173.static.twtelecom.net (207.71.33.173)         0.0%    10   60.0  57.2  37.7 139.2  30.2
  3. AS3549   ae0-250g.ar1.dal1.gblx.net (67.17.95.74)                   0.0%    10   48.8  60.3  48.3  85.3  12.5
  4. AS???    ???                                                       100.0    10    0.0   0.0   0.0   0.0   0.0
  5. AS???    ???                                                       100.0    10    0.0   0.0   0.0   0.0   0.0
  6. AS3356   github-inc.bear1.washington111.level3.net (4.53.116.102)   0.0%    10   78.6  84.0  76.2 100.7   8.1
  7. AS???    ???                                                       100.0    10    0.0   0.0   0.0   0.0   0.0
  8. AS???    ???                                                       100.0    10    0.0   0.0   0.0   0.0   0.0
  9. AS36459  192.30.253.112                                             0.0%    10   83.5 120.1  78.2 278.8  74.6

From this output you can see that:

• some hops have disabled responding to ICMP network traffic
• overall latency range: 78.2ms - 278.8ms
• average latency: 120.1ms

what are all those flags:

• -w: print layout set to report mode (so that hostnames print properly)
• -b: include IP addresses
• -z: include autonomous system number (ASN) -- a unique routing identifer
• -c: specify a count -- how much traffic you want the test to pass before kicking out the report (10 is not a very good test, but 100 is probably a better longer term view of the current state of networking)

[ruebenramirez]

on mac install mtr with:

brew install mtr
ln /usr/local/Cellar/mtr/0.87/sbin/mtr /usr/local/bin/mtr

(note: 0.87 is the current release version that gets installed, ymmv)

...then use with sudo

[ruebenramirez]

https://www.digitalocean.com/community/tutorials/how-to-use-traceroute-and-mtr-to-diagnose-network-issues

[ruebenramirez]

https://www.maxcdn.com/one/tutorial/how-to-read-a-traceroute/