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!
Do you have some device on your network that responds to pings for addresses that can't be routed?
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.
Well, then... the first question to you is, what are the differences between traceroute and ping?
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. :o
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?
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.
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.
Can you share the packet tracer file?
opened that packet tracer file before sending out but then now i can no longer ping 100.100.100.4!