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About traceroute from destination to the source

markhui222
Level 1
Level 1

We use traceroute to trace the hops pass through from source to the destination.

 

Is there any way to show the hops for the return packet passed through from destination to source?  

2 Replies 2

Giuseppe Larosa
Hall of Fame
Hall of Fame

Hello @markhui222 ,

with a limitation of max 9 router hops there is an option in extended ping that can show the return path and I think it is record route.

 

Hope to help

Giuseppe

 

The original post refers to an interesting potential issue. We tend to assume that traffic through networks will be symmetric (the path used from source to destination will be the same as the path for responses from destination to source). But that is not always the case. Sometimes from destination to source will take a different path. So how can we detect this? The record route option is the best one that I know where you are doing all of the work. The optimum solution would be for you to do a traceroute from source to destination and to have someone at the destination do a traceroute to you and send you the results.

If we are using traceroute for some analytical purpose, then there is another potential issue, especially if the traceroute goes over the Internet (instead of being entirely within an enterprise network). Over time the path used by traceroute may change. If you do a traceroute now, wait 10 minutes, and do the same traceroute again will it perhaps take a different path?

So perhaps we need to understand a bit better the purpose of doing these traceroutes. If it is to check on connectivity, and especially to identify where problems with connectivity may occur, then traceroute can be very helpful (but is it important to know if traffic is symmetric). If the traceroute is for some type of traffic engineering then we need to be cautious about the results.

HTH

Rick
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