Traceroute result that no stop even reach destination ip

angel.lim · ‎02-20-2013

Dear All,

Need assistant for below question.

-When doing traceroute from A location, the traceroute result has reached destination ip, why it still continue until hops 30 ?

-But, when doing traceroute from B location, the traceroute result to the same destination ip will stop at the destination ip without continue to hops 30.

For example (below traceroute ip are just an example)

213.17.214.101 is a router gateway

213.17.214.102 is a server riding behind 213.17.214.101.

Traceroute result from A location

> traceroute 213.17.214.101

traceroute to 213.17.214.101 (213.17.214.101), 30 hops max, 40 byte packets

1 222.14.67.252 0.638 ms 0.571 ms 0.536 ms

2 222.64.154.65 0.305 ms 0.284 ms 0.264 ms

3 222.64.5.122 0.558 ms 0.602 ms 0.492 ms

4 119.92.191.131 0.470 ms 0.495 ms 0.519 ms

5 213.17.214.101 4.526 ms 4.500 ms 4.481 ms <<<<< it reached destination, but why it still continue until hops 30?

6 * * *

7 * * *

until

30 * * *

When traceroute to device 213.17.214.102, it will stop at 213.17.214.102 without continue to hops 30.

> traceroute 213.17.214.102

traceroute to 213.17.214.102 (213.17.214.102), 30 hops max, 40 byte packets

1 222.14.67.252 0.638 ms 0.571 ms 0.536 ms

2 222.64.154.65 0.305 ms 0.284 ms 0.264 ms

3 222.64.5.122 0.558 ms 0.602 ms 0.492 ms

4 119.92.191.131 0.470 ms 0.495 ms 0.519 ms

5 213.17.214.101 4.526 ms 4.500 ms 4.481 ms

6 213.17.214.102 4.620 ms 4.621 ms 4.611 ms <<<< it stop at destination ip without continue traceroute action.

Traceroute result from B location:-

C:\>tracert 213.17.214.101

Tracing route to 213.17.214.101 over a maximum of 30 hops

1 1 ms <1 ms <1 ms 10.130.68.15

2 <1 ms 12 ms 11 ms 10.130.254.129

3 11 ms 11 ms 11 ms 10.130.190.14

4 11 ms 12 ms 11 ms 222.147.39.129

]

5 43 ms 42 ms 41 ms 62.14.157.102

6 42 ms 41 ms 41 ms 212.147.16.202

7 42 ms 42 ms 41 ms 212.147.16.102

8 71 ms 200 ms 204 ms 203.191.151.22

6]

9 * * * Request timed out.

10 * * * Request timed out.

11 42 ms 41 ms 41 ms 119.92.191.131

12 50 ms 65 ms 60 ms 213.17.214.101 <<<<<<<<< it will stop here without continue to hops 30.

Any reason why at A location doing traceroute to 213.17.214.101 and it still continue for the traceroute action even it reach destination? But for traceroute to the device 213.17.214.102 that behind the router and it will stop without continue the traceroute action?

And doing the traceroute to the same destionation ip from others location such as location B, it will stop at destionation ip without continue to hops 30.

Regards,

Angel

prakadeesh · ‎02-21-2013

Hi,

Are they on the same subnet or are they defined as /32 and crossing a lot IP of hops? The address range seems close enough hence this query

angel.lim · ‎02-21-2013

Hi prakadeesh,
The source ip and destination ip is different subnet. As it is an internet broadband connection where it pass through different ISP hops.

Sent from Cisco Technical Support Android App

prakadeesh · ‎02-22-2013

Hi angel.lim,

Now I understand the query better, i thought the IP addresses were the locations A and B . Ok the whole world of Traceroute is built upon the ICMP port unreachable message. So when the tracert destination has reached, the destination device will reply to the sender an ICMP port unreachable, completing the traceroute. Until the source recieves this the traceroute will increment the TTL and will carry on. I think the router has its ICMP port unreachable disabled.

angel.lim · ‎02-22-2013

If the router .101 was icmp port unreachable disabled, why am I doing the traceroute at location B at the same time with the person who doing the traceroute at location A and my traceroute will stop at destination ip but person who done it at location A won't stop at destination? Both results are done at the same time. .

Sent from Cisco Technical Support Android App

jvdavim · ‎08-19-2018

Hi, angel.lim.

It's because the tracert program is different from traceroute program.

The tracert sends ICMP Echo Request packets while traceroute sends UDP packets with invalid port number.
The tracert stops when gets an ICMP Echo Reply, while traceroute stops when gets ICMP Port Unreachable.

If you use traceroute in B location too, then you should have the same 30 hops output.

It happens because the destination could be not sending ICMP Port Unreachable, but it's sending ICMP Echo Reply. Then tracert works well while traceroute continue until reach 30 hops.

Try to use the traceroute from B location with the flag -l. This way: traceroute -I 213.17.214.101