The Mad Philosopher

“mtr combines the functionality of the traceroute and ping programs in a single network diagnostic tool.” And it’s really cool.

Like ping, it sends “echo” packets from your machine to the target machine to measure latency and packet loss along the network path, but it continuously displays updated statistics in real time as it operates.

Like traceroute, it shows the names or IP addresses of each machine along the network path, also updating these statistics for each machine.

Here’s some (frozen) sample output from the ncurses mode (terminal mode) mtr:

                                My traceroute  [v0.71]
exobox (0.0.0.0)                                             Thu Dec 21 16:15:01 2006
Keys:  Help   Display mode   Restart statistics   Order of fields   quit
                                             Packets               Pings
 Host                                      Loss%   Snt   Last   Avg  Best  Wrst StDev
 1.                                         0.0%    20    0.4   0.3   0.2   0.7   0.1
 2.                                         0.0%    20    1.6   1.4   1.0   2.7   0.4
 3.                                         0.0%    19    1.3   1.3   1.0   2.7   0.4
 4. 10.0.0.25                               0.0%    19    1.1   1.2   1.0   2.7   0.4
 5. 219.142.10.17                           0.0%    19    1.4   2.6   1.2  16.0   3.3
 6. bj141-130-121.bjtelecom.net             0.0%    19    1.4   1.6   1.4   2.5   0.3
 7. 202.97.57.221                           0.0%    19  199.3  12.0   1.3 199.3  45.4
 8. 202.97.37.9                             0.0%    19    1.7  35.7   1.3 186.5  56.2
 9. 202.97.53.146                           0.0%    19    1.8   2.0   1.5   4.8   0.8
10. 202.97.61.50                            0.0%    19  284.6 292.2 278.3 305.8   8.7
11. so-4-0-0.mpr2.lax9.us.above.net        15.8%    19  286.2 291.9 278.6 325.2  11.5
12. so-5-0-0.mpr1.iah1.us.above.net        15.8%    19  313.2 323.8 311.3 340.5   8.6
13. so-5-3-0.cr1.dfw2.us.above.net          5.3%    19  319.6 331.1 314.1 404.6  20.3
14. so-0-0-0.cr2.dfw2.us.above.net         11.1%    19  696.0 718.7 693.3 797.2  33.7
15. so-3-1-0.cr2.dca2.us.above.net         36.8%    19  347.4 354.9 342.5 368.7   8.6
16. so-0-1-0.mpr1.lhr3.uk.above.net        11.1%    19  421.5 423.6 411.1 438.2   7.8
17. so-1-0-0.mpr3.ams1.nl.above.net        11.1%    19  433.9 438.9 422.4 514.1  22.0
18. DutchDSL.above.net                     33.3%    19  423.1 432.7 418.7 463.0  11.4
19. ge-0-1-0-v189.rtr1.ams-rb.io.nl        27.8%    19  405.8 414.7 398.2 434.6  11.6
20. 213.196.40.242                         23.5%    18  404.8 418.1 399.9 485.8  21.9

Looking at the Avg column (units in ms), the above output shows that my network packets pass through Beijing Telecom’s routers to the U.S., then to the U.K., and finally to their destination in the Netherlands. A large latency increase occurs between lines 9 and 10 (presumably leaving P.R. China), and another between lines 13 and 16 (U.S. to U.K.).

mtr has some interesting display modes besides the above, where it shows the latency of each packet graphically according to a dynamic scale. In this way, the above points of really large latency can be easily detected.

mtr can be obtained from the mtr website, or it can be installed in Debian/Ubuntu by:

# apt-get install mtr-tiny

or

# apt-get install mtr

for the ncurses or X11 versions, respectively, although mtr-tiny appears to be installed by default in the Debian and Ubuntu machines I have tested. So you may already have it.

I just discovered vnStat, a network traffic monitor for Linux. Here’s a blurb from the website:

vnStat is a network traffic monitor for Linux that keeps a log of daily network traffic for the selected interface(s). vnStat isn’t a packet sniffer. The traffic information is analyzed from the /proc -filesystem, so vnStat can be used without root permissions.

It will tell you how much inbound and outbound bandwidth that your Linux machine is using—hourly, daily, weekly, monthly, yearly. That’s handy.

By inspection, I’ve been able to tell that it runs like so: it installs itself as a cron job that runs every five minutes to update its internal database. Then you can type vnstat on the command line to give you the stats.

I’d post some sample output, but since I’ve just started running it, there’s nothing to show. I’m glad to have found it, though.