can ping but can not traceroute certain route

[ggnfs000]

show ip route shows one R flagged address (rip v2 learned) which is valid route. The address was 100.100.100.4
I simply dont see this address anywhere in the network, period.

So I can presume that some reason it is stale route and ripv2 did not manage to remove through routing updates which itself weird but...

But I can ping it!
And can not traceroute it!

[deanwebb]

Do you have some device on your network that responds to pings for addresses that can't be routed?

[ggnfs000]

nope. this actually on packet trace software simulation with 4 routers and 2 switches.

wonder if it is a software bug.
will keep looking.
looks like a good troubleshooting exercise.

[deanwebb]

Well, then... the first question to you is, what are the differences between traceroute and ping?

[ggnfs000]

Same except, well TTL starts from 0 for traceroute. What perplexes is how in the hell it is possible that ping can reach the non-existing target whereas traceroute can not. Trace route can ping next-hop but then after that goes blank. 

[deanwebb]

Keep thinking... how does a ping packet travel vs. how a traceroute packet? What is the difference in how they are handled by devices on the network?

[ggnfs000]

so upon closer investigation, 100.100.100.4 was subnet showing up in "show ip route".
The actual interface in those subnets are 100.100.100.5 and 6 with mask 255.255.255.252 or /30.
still it does not describe why I ping 100.100.100.4.
Perhaps routing in IOS allows ping the subnet address somehow? Perhaps it is a "route to network"? Not only I can ping 100.100.100.4 also was able to ping subnet broadcast address 100.100.100.7.

As a comparison, I got home NAT subnet with 10.0.0.0 network, I can definitely NOT ping 10.0.0.0 let alone traceroute.

[Dieselboy]

You're thinking too broad, OP. Take a few steps back. I could be wrong, of course but - usually when I can ping but trace route is failing [somewhere] I go to [somewhere] and look at possibly why traceroute is not getting through [somewhere].

Hint: traceroute and ping are both icmp but they're different.

[SimonV]

Can you share the packet tracer file?

[ggnfs000]

opened that packet tracer file before sending out but then now i can no longer ping 100.100.100.4!