One query about traceroute.
If packet drops getting on any hope while doing traceroute to destination.
Is it issue with ISP or might be ping blocked by ISP on that hope.
Is ISP does these things in bewteen hopes.
Please see the below scenaro.
Getting packet drop 4th and 10th hope. Ignore packet drop after 20th hope.It is acceptable as destination tracert completed at 19th hope.
Real IP's hided in below example.
1 14 ms 2 ms 2 ms 192.168.1.1
8 138 ms 138 ms 138 ms
9 226 ms 247 ms 226 ms
10 * * * Request timed out.
11 222 ms 222 ms 222 ms
12 274 ms 273 ms 274 ms
13 278 ms 274 ms 274 ms
14 273 ms 274 ms 274 ms
15 275 ms 274 ms 277 ms
16 273 ms 274 ms 277 ms
17 277 ms 274 ms 274 ms
18 276 ms 276 ms 272 ms
19 273 ms 277 ms 277 ms 22.214.171.124 Required host tracert completed here.
20 * * * Request timed out.
21 * * * Request timed out.
22 * * * Request timed out.
23 * * * Request timed out.
24 * * * Request timed out.
25 * * * Request timed out.
26 * * * Request timed out.
27 * * * Request timed out.
28 * * * Request timed out.
29 * * * Request timed out.
30 * * * Request timed out.
Well, we have to understand a little bit about how traceroute works. And part of that will depend on what OS we are talking about!
Micro$oft tends to use ICMP with a variable TTL, so it's JUST like doing a ping. Some devices will filter pings, so you may have a whole slew that simply don't respond.
Unix (and Cisco IOS is a derivative thereof) use a UDP packet with variable TTL. Again, there may be filter issues involved.
Either way though, your interim routers SHOULD see that TTL doesn't allow them to forward and respond with an ICMP - TTL-Exceeded message. If a router/device in the middle has "no ip unreachables" configured, then it will NOT respond, and that's expected behavior.
When you reach the end station, assuming there's nothing listening to the UDP port being used, then you should get an ICMP - Port-unreachable message back and that's how you know it's completed.
If your traceroute properly completed, you'd have it end. The fact that you have "request timed out" messages AFTER you say it completed tells me that it did not properly complete due to some filtering/ACL.
Thanks for detail expalination.
ISP might be configured no ip reachables commands .So I do not worry about it.