http://www.itworld.com/operating-systems/433991/unix-better-network-connection-insights-mtr
The mtr tool -- "my traceroute", originally "Matt's traceroute" for the
guy that first developed it (Matt Kimball in 1997) -- is in some ways
like a combination of traceroute and ping and it provides a lot more
data than the two of these commands combined.
Like ping and traceroute, mtr uses icmp packets to test connections. While traceroute is likely to be installed on every Unix system you use, you may have to separately install mtr. If you do, here are some commands for doing so:
The latency (round trip) measurement is the timestamp when ICMP reply is received minus the timestamp when the probe was launched.
By default, traceroute issues three probes aper hop, thus you will see three numbers for each hop in the traceroute output.
Here is some sample traceroute output:
It also shows you the packet loss -- like ping.
The mtr command also shows you a number of statistics for each leg in the route. The columns in the output (see example below) represent:
You can ask for a report using syntax like this:
Some people who use mtr routinely for troubleshooting network connections suggest that you run reports in both directions if you want to fully diagnose your connection issues.
Traceroute is still a great tool, but mtr ("my traceroute") provides even more insights when you're looking into network routing problems.
Like ping and traceroute, mtr uses icmp packets to test connections. While traceroute is likely to be installed on every Unix system you use, you may have to separately install mtr. If you do, here are some commands for doing so:
- Ubuntu or Debian systems: apt-get install mtr
- Fedora or Centos: yum install mtr
- Mac OS X: brew install mtr
- FreeBSD: pkg install net/mtr
The latency (round trip) measurement is the timestamp when ICMP reply is received minus the timestamp when the probe was launched.
By default, traceroute issues three probes aper hop, thus you will see three numbers for each hop in the traceroute output.
Here is some sample traceroute output:
$ traceroute world.pts.com traceroute to world.pts.com (192.74.137.5), 30 hops max, 40 byte packets 1 pix (192.168.0.2) 0.255 ms 0.478 ms 0.443 ms 2 * * * 3 gig1-6.umcp-core.net.doz.org (136.160.255.33) 9.856 ms 9.343 ms 9.822 ms 4 ten2-0.stpaul-core.net.doz.org (136.160.255.198) 3.401 ms 3.858 ms 3.681 ms 5 te4-3.ccr01.bwi01.atlas.cogentco.com (38.104.12.17) 2.920 ms 2.859 ms 3.280 ms 6 te4-2.ccr01.phl01.atlas.cogentco.com (154.54.2.174) 5.965 ms 5.945 ms 5.920 ms 7 te0-0-0-7.ccr22.jfk02.atlas.cogentco.com (154.54.31.53) 9.084 ms te0-0-0-7.ccr21. jfk02.atlas.cogentco.com (154.54.1.41) 8.811 ms te0-0-0-7.ccr22.jfk02.atlas.cogentco. com (154.54.31.53) 8.784 ms 8 be2096.ccr22.bos01.atlas.cogentco.com (154.54.30.42) 14.991 ms be2094.ccr21.bos01 .atlas.cogentco.com (154.54.30.14) 14.764 ms be2096.ccr22.bos01.atlas.cogentco.com (154.54.30.42) 14.964 ms 9 te4-1.mag02.bos01.atlas.cogentco.com (154.54.43.70) 14.478 ms te4-1.mag01.bos01. atlas.cogentco.com (154.54.43.50) 14.201 ms 14.171 ms 10 gi0-0-0-0.nr11.b000502-0.bos01.atlas.cogentco.com (154.24.6.237) 14.891 ms 16 .941 ms 16.702 ms 11 cogent.bos.ma.towerstream.com (38.104.186.82) 14.699 ms 14.188 ms 14.220 ms 12 g6-2.cr.bos1.ma.towerstream.com (64.119.143.81) 14.904 ms 14.903 ms 14.888 ms 13 69.38.149.18 (69.38.149.18) 18.293 ms 34.857 ms 33.138 ms 14 64.119.137.154 (64.119.137.154) 33.122 ms 36.814 ms 36.329 ms 15 world.pts.com (192.74.137.15) 34.369 ms 34.567 ms 29.696 msThe mtr command differs from traceroute in several ways. First, like top, it provides a table of values that refreshes itself every second or so, allowing you to see how the values are updated over time. You can slow this down by giving the command a -i or --interval argument and specify the seconds you want to pass between each update.
It also shows you the packet loss -- like ping.
The mtr command also shows you a number of statistics for each leg in the route. The columns in the output (see example below) represent:
- Snt -- number of packets sent
- Loss% -- percentage of packets lost at each hop (can change with --report-cycles=#
where # is replaced by the number of packets you want to send - Last -- latency of the last packet sent
- Avg -- average latency
- Best -- shortest round trip
- Wrst -- longest round trip
- StDev -- standard deviation
My traceroute [v0.71]
boson.xyz.org (0.0.0.0) Sun Aug 31 16
:22:55 2014
Keys: Help Display mode Restart statistics Order of fields quit
Packets Pings
Host Loss% Last Avg Best Wrst StDev
1. 192.168.0.1 50.0% 0.4 0.4 0.4 0.4 0.0
2. ???
3. gig1-6.umcp-core.net.doz.org 0.0% 1.6 4.0 1.6 6.6 2.5
4. ten2-0.stpaul-core.net.doz.org 0.0% 2.7 2.8 2.7 2.8 0.1
5. te4-3.ccr01.bwi01.atlas.cogentco.com 0.0% 91.5 32.3 2.7 91.5 51.2
6. te4-2.ccr01.phl01.atlas.cogentco.com 0.0% 5.6 11.6 5.6 23.4 10.2
7. te0-0-0-19.mpd21.jfk02.atlas.cogentco.com 0.0% 8.8 8.7 8.7 8.8 0.1
8. be2095.ccr21.bos01.atlas.cogentco.com 0.0% 14.5 14.4 14.3 14.5 0.1
9. te4-1.mag01.bos01.atlas.cogentco.com 0.0% 14.1 14.2 14.1 14.3 0.1
10. gi0-0-0-0.nr11.b000502-0.bos01.atlas.com 0.0% 14.7 14.6 14.6 14.7 0.1
11. cogent.bos.ma.towerstream.com 0.0% 14.1 14.1 14.1 14.1 0.1
12. g6-2.cr.bos1.ma.towerstream.com 0.0% 14.8 14.8 14.8 14.8 0.0
13. 69.38.149.18 0.0% 24.0 26.9 24.0 29.7 4.1
14. 64.119.137.154 0.0% 28.5 28.5 28.5 28.5 0.0
15. world.pts.com 0.0% 23.3 22.2 21.1 23.3 1.5
Another often used mtr command is to use the -r or --report command.
This gives you a static report (rather than updating every second).
Instead, it runs through 10 iterations (or whatever you tell it using
the -c (count) or --report-cycles option and shows you the result at the
end.You can ask for a report using syntax like this:
mtr --report mtr --report
$ mtr world.pts.com --report boson.xyz.org Snt: 10 Loss% Last Avg Best Wrst StDev pix 50.0% 0.4 0.4 0.4 0.4 0.0 ??? 100.0 0.0 0.0 0.0 0.0 0.0 gig1-6.umcp-core.net.doz.org 0.0% 12.6 4.0 1.5 12.6 3.6 ten2-0.stpaul-core.net.doz.org 0.0% 8.2 5.3 2.7 13.0 4.1 te4-3.ccr01.bwi01.atlas.cogentco.com 0.0% 2.9 33.4 2.6 139.2 52.1 te4-2.ccr01.phl01.atlas.cogentco.com 0.0% 5.7 52.9 5.5 201.2 74.9 te0-0-0-19.mpd21.jfk02.atlas.cogentco.com 0.0% 8.5 8.6 8.5 8.7 0.1 be2095.ccr21.bos01.atlas.cogentco.com 0.0% 14.4 14.6 14.3 15.0 0.2 te4-1.mag01.bos01.atlas.cogentco.com 0.0% 14.5 28.5 14.0 157.2 45.2 gi0-0-0-0.nr11.b000502-0.bos01.atlas.cogentc 0.0% 15.0 14.8 14.7 15.1 0.2 cogent.bos.ma.towerstream.com 0.0% 14.1 27.0 14.0 136.0 38.4 g6-2.cr.bos1.ma.towerstream.com 0.0% 15.9 15.0 14.8 15.9 0.3 69.38.149.18 0.0% 22.6 23.5 18.3 34.2 4.7 64.119.137.154 10.0% 23.0 25.4 19.6 32.0 4.7 world.pts.com 0.0% 21.9 23.7 19.2 29.9 3.6Both packet loss and latency tell you a lot about the quality of your connections. A large loss will indicate a problem with the particular router. Note in the second line above, we see 100% loss. This router is not sending anything back to us, though this doesn't mean that it isn't a functional router. Obviously, the connections are reaching the final destination. But the router is probably not allowing icmp traffic to go back to the source or is taking too long. The ??? indicates timeouts. Some loss that you see may be due to rate limiting settings on routers.
Some people who use mtr routinely for troubleshooting network connections suggest that you run reports in both directions if you want to fully diagnose your connection issues.
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