Help_Topics

Interpreting traceroute data

When an X strike error occurs, a traceroute is run on the agent. This information is then collated and included in an e-mail sent to the diagnostic contact(s) for the affected service.

Traceroute (Standard Agents)

Traceroute Legend

HOST Hostname at hop
LOSS Percent packet loss
RCVD Number of packets received
SENT Number of packets sent
BEST Best response time in milliseconds
AVG Average response time in milliseconds
WORST Worst response time in milliseconds

Sample Traceroute

For reference, a sample traceroute is included below:

The following traceroute to 66.253.74.6 was generated from St. Louis, MO (206.196.98.41):
HOST                                    LOSS  RCVD SENT    BEST     AVG   WORST
static-206.196.98.254.primary.net         0%     2    2    0.92    9.15   17.37
stl-core-01.primary.net                   0%     2    2    2.12    2.42    2.71
acr1-so-3-2-0.chicago.savvis.net          0%     2    2    7.81    8.20    8.59
cr1-pos-0-3-3-2.chicago.savvis.net        0%     2    2    8.72    9.27    9.82
204.70.195.114                            0%     2    2    7.91    7.95    7.98
ber1-vlan-241.chicagoequinix.savvis.net   0%     2    2    7.83    7.94    8.04
208.173.180.22                            0%     2    2    7.81   11.76   15.71
cer-core-02.inet.qwest.net                0%     2    2    7.89    8.03    8.17
los-core-01.inet.qwest.net                0%     2    2   64.86   73.54   82.22
bux-edge-01.inet.qwest.net                0%     2    2   64.93   65.07   65.22
63.145.160.174                            0%     2    2   70.20   70.45   70.70
???                                     100%     0    2    0.00    0.00    0.00

This particular traceroute indicates a potential problem at the last hop as both packets sent were not able to reach their destination. This could be for a number of reasons, but the two most likely causes are:

  1. A legitimate network routing issue where packets aren't being routed to the destination appropriately.
  2. ICMP echo traffic is blocked by that particular host.

Traceroute (RIA and Streaming Agents)

Traceroute Legend

Hop Hop number
RTT Round Trip Time in milliseconds
Source to Here
Lost/Sent = Pct
Number of lost packets from the source to the current hop / Number of sent packets from the source to the current hop = Percentage loss
This Node/Link
Lost/Sent = Pct
Number of packets lost at this node / Number of packets sent at this node = Percentage loss
Address This hop's IP address

Sample Traceroute

            Source to Here   This Node/Link
Hop  RTT    Lost/Sent = Pct  Lost/Sent = Pct  Address
  0                                           208.73.222.10
                                0/   1 =  0%   |
  1    1ms     0/   1 =  0%     0/   1 =  0%  208.73.222.9
                                0/   1 =  0%   |
  2    1ms     0/   1 =  0%     0/   1 =  0%  209.195.4.145
                                0/   1 =  0%   |
  3    1ms     0/   1 =  0%     0/   1 =  0%  209.195.2.165
                                0/   1 =  0%   |
  4   17ms     0/   1 =  0%     0/   1 =  0%  205.234.16.241
                                0/   1 =  0%   |
  5   17ms     0/   1 =  0%     0/   1 =  0%  209.10.10.137
                                0/   1 =  0%   |
  6   21ms     0/   1 =  0%     0/   1 =  0%  209.10.10.133
                                0/   1 =  0%   |
  7   26ms     0/   1 =  0%     0/   1 =  0%  209.10.12.166
                                1/   1 =100%   |
  8  ---       1/   1 =100%     0/   1 =  0%  0.0.0.0

Trace complete.

This particular traceroute indicates a potential problem at the last hop as both packets sent were not able to reach their destination. This could be for a number of reasons, but the two most likely causes are:

  1. A legitimate network routing issue where packets aren't being routed to the destination appropriately.
  2. ICMP echo traffic is blocked by that particular host.

Important Technical Notes about traceroute

  • Note that since many network providers block ICMP echo traffic, there may be particular hops that have "???" or "---" under the HOST column. For this reason, traceroute data must be interpreted carefully and in conjunction with other diagnostic information such as alerts and and log files from the affected device(s).
  • Standard agents execute a traceroute using mtr or Matt's Traceroute.
  • RIA and Streaming agents execute a traceroute using a utility called pathping.

See also

About_alerts
Run_a_traceroute_from_a_Webmetrics_agent_to_a_site