Understanding Traceroute and Missing Hops

A discussion about missing hops in a traceroute was had, with a user providing a possible explanation that some nodes may not allow ICMP ping. It was suggested to use the Windows tracert command to replicate this. Other users chimed in with similar experiences and further clarification on how traceroute works. It was concluded that this can be a temporary issue or it may be due to nodes not allowing ICMP traffic. The example used to demonstrate this was pinging Google, which does not allow ICMP ping. The initial user thanked everyone for their help.

Read the entire ‘Understanding Traceroute and Missing Hops’ thread below:

Is anyone make to provide some clarity into why some hops are missing when at a looking at a traceroute? For users we see this with, they seem to have more audio issues than others (running Citrix on iGel. ControlUp is installed on iGel side and trace is from it). For these affected users it always seem like its the first few hops. here is an example. You can see hops two and 3 are missing:

Some hops do not allow traceroute (ICMP ping). Those would be missing. You should be able to replicate this with Windows tracert. For example, me pinging Google. Hops 14 and 15 time out.

Could be that there was a temporary issue. Or whoever operates those nodes doesn’t allow ICMP traffic

PS, google.com is a bad example because it appears they don’t allow ICMP ping either. So google.com wouldn’t show up at all. As in if the destination cannot be pinged at all, the entire trace route wouldn’t show. Nor would the latency itself.

I used it because it was an easy example of nodes who appear to block ICMP ping along the route

Thank you!

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