[outages] META: Tracing outages and paths

[Jay Ashworth]

[ Please direct followups to outages-discuss; still trying to find a way to
get Zimbra to let me add the header manually... -- jra ]

Just a reminder: if you're having trouble with access to a service over the
internet (and you don't already know this; gimme a break :-), one of the
most useful bits of data you can provide in your report is a traceroute,
and (my favorite) tool for this is mtr.  The Linux version is probably
a bit more useful than the Windows version, but both are available, and
provide better statistical data than the standard traceroute, or ghod 
forbid, just a ping (RIPMM).

I usually use:

# mtr -r 10 -c hostname.example.com

which provides output like this:

HOST: janus                       Loss%   Snt   Last   Avg  Best  Wrst StDev
  1. 192.168.1.1                   0.0%    10    0.2   0.3   0.2   0.4   0.0
  2. 192.168.2.1                   0.0%    10    1.6   1.3   1.0   2.1   0.4
  3. ???                          100.0    10    0.0   0.0   0.0   0.0   0.0
  4. gig13-0-0-2005.tampfledc-rtr  0.0%    10   10.9  12.1   8.9  28.4   5.8
  5. 72-31-220-11.net.bhntampa.co  0.0%    10   10.0  11.6   8.7  21.6   3.9
  6. 72-31-3-245.net.bhntampa.com  0.0%    10   10.2  21.1   9.2  69.9  21.9
  7. rrcs-67-79-131-166.se.biz.rr  0.0%    10   14.8  12.6  10.3  20.6   3.1
  8. te3-4.co2.as30217.net         0.0%    10   12.8  12.3  10.9  14.1   1.1
  9. 10ge5-1.csw5-pmtpa.wikimedia  0.0%    10   19.0  12.4  10.0  19.0   2.5
 10. rr.pmtpa.wikimedia.org        0.0%    10   13.3  11.9  11.1  13.3   0.7

Note that the only thing mtr's -r mode does *not* do is provide both 
the reverse DNS looked-up names, *and* the IP addresses, so including the 
output of 

# mtr -r 10 -c -n hostname.example.com

as well may be useful, especially since mtr clips off the names to fit in all 
the stats.

HOST: janus                       Loss%   Snt   Last   Avg  Best  Wrst StDev
  1. 192.168.1.1                   0.0%    10    0.3   0.3   0.2   0.9   0.2
  2. 192.168.2.1                   0.0%    10    1.1   1.4   1.0   3.1   0.6
  3. ???                          100.0    10    0.0   0.0   0.0   0.0   0.0
  4. 65.32.37.146                  0.0%    10   10.9  10.8   8.9  14.1   1.4
  5. 72.31.220.11                  0.0%    10   11.6  11.5   9.4  17.4   2.3
  6. 72.31.3.245                   0.0%    10   10.9  27.2   9.9 111.7  34.0
  7. 67.79.131.166                 0.0%    10   11.6  12.3  11.1  14.3   1.0
  8. 84.40.24.50                   0.0%    10   11.9  11.6  10.6  12.8   0.6
  9. 84.40.25.102                  0.0%    10   13.5  12.0  10.7  14.5   1.2
 10. 208.80.152.2                  0.0%    10   13.3  12.0  10.7  15.2   1.6

Since that command takes 10 seconds to run, you won't get any output at all 
for those 10 seconds; try not to wig out.

mtr is in all the major distro repo's, I believe, though it's generally 
not installled by default; it's on my list of Things To Install Automatically.

Cheers,
-- jr 'this was a just a test.  If this had been an *actual* outage...' a
-- 
Jay R. Ashworth                  Baylink                       jra at baylink.com
Designer                     The Things I Think                       RFC 2100
Ashworth & Associates     http://baylink.pitas.com         2000 Land Rover DII
St Petersburg FL USA      http://photo.imageinc.us             +1 727 647 1274