Networking / Beginners

Verifying the Routed Path with pathping

pathping is a combination of both ping and tracert. It starts by checking the route between the two computers similar to how tracert does so. It then uses ping to check for connectivity at each router.

It will send each router 100 echo request commands, and it expects to receive 100 echo replies back. It then calculates the percentage of data loss based on what it receives. For example, if it receives 100 replies, there is 0 percent packet loss. However, if it receives only 95 replies, there is 5 percent packet loss.

Listing-6 shows the output of a pathping command. Notice that in the first part of the pathping process, it checks the path similar to tracert. Lines 1 through 13 represent routers identified as hops. After it calculates the path, it then starts calculating the statistics by measuring loss. By default, the calculation process takes five minutes.

Listing-6: Output of pathping command
C:\Users\Dar>pathping microsoft.com 
  
Tracing route to microsoft.com [207.46.197.32] 
over a maximum of 30 hops: 
  0  Laptop.hr.cox.net [192.168.1.114] 
  1   [192.168.1.1] 
  2  10.10.184.1 
  3  68.10.14.77 
  4  172.22.48.33 
  5  nrfkdsrj02-ge600.0.rd.hr.cox.net [68.10.14.17] 
  6  ashbbprj02-ae4.0.rd.as.cox.net [68.1.1.232] 
  7  209.240.199.130 
  8  ge-3-1-0-0.blu-64c-1a.ntwk.msn.net [207.46.47.29] 
  9  xe-0-1-3-0.ch1-16c-1a.ntwk.msn.net [207.46.46.169] 
 10  ge-3-1-0-0.co1-64c-1a.ntwk.msn.net [207.46.46.118] 
 11  ge-1-0-0-0.wst-64cb-1a.ntwk.msn.net [207.46.43.163] 
 12  ge-7-1-0-0.cpk-64c-1b.ntwk.msn.net [207.46.43.228] 
 13  ten3-4.cpk-76c-1a.ntwk.msn.net [207.46.47.197] 
 14     *        *        * 
Computing statistics for 325 seconds... 
            Source to Here   This Node/Link 
Hop  RTT    Lost/Sent = Pct  Lost/Sent = Pct  Address 
  0                                           [192.168.1.114] 
  
                                0/ 100 =  0%   | 
  1    3ms     0/ 100 =  0%     0/ 100 =  0%   [192.168.1.1] 
                                0/ 100 =  0%   | 
  2  ---     100/ 100 =100%   100/ 100 =100%  10.10.184.1 
                                0/ 100 =  0%   | 
  3   11ms     0/ 100 =  0%     0/ 100 =  0%  68.10.14.77 
                                0/ 100 =  0%   | 
  4  ---     100/ 100 =100%   100/ 100 =100%  172.22.48.33 
                                0/ 100 =  0%   | 
  5   14ms     0/ 100 =  0%     0/ 100 =  0%   
                          nrfkdsrj02-ge600.0.rd.hr.cox.net 
                           [68.10.14.17] 
                                0/ 100 =  0%   | 
  6   25ms     0/ 100 =  0%     0/ 100 =  0%   
                          ashbbprj02-ae4.0.rd.as.cox.net 
                           [68.1.1.232] 
                                0/ 100 =  0%   | 
  7   21ms     0/ 100 =  0%     0/ 100 =  0%  209.240.199.130 
                              100/ 100 =100%   | 
  8  ---     100/ 100 =100%     0/ 100 =  0%   
                          ge-3-1-0-0.blu-64c-1a.ntwk.msn.net 
                           [207.46.47.29] 
 . . . 
 Trace complete.

The last few hops are similar to hop 8 and aren't listed. They are showing 100 percent loss since 100 packets were sent and 100 packets were lost. Again, this is likely because the routers are blocking ICMP, not because there is actual data loss.

If you have a large network with many routers, the pathping command can be useful to help you identify whether you are experiencing any data loss at specific routers. It could be that the routers simply have too much traffic for their capacity. You can either offload some of the traffic to another subnet or increase the capacity of the router.

Table-5 lists some additional switches you can use with the pathping command.

Table-5 Some pathping switches
Switch 				Comments
-4 pathping -4 microsoft.com 	Forces the use of an IPv4 address instead of IPv6. 
-6 pathping -6 microsoft.com 	Forces the use of an IPv6 address instead of IPv4. 
-n pathping -n microsoft.com 	Suppresses IP address to name resolution. Only the
				IP addresses are listed. 
-q pathping -q 50 microsoft.com Changes the number of queries per hop. By default, 100
				queries per hop are used.
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