Unknown traceroute

Answered Question
Sep 11th, 2009

Hi all,

Does anyone know what the following traceroute mean ? I can ping to the ip but can't show the traceroute destination.

------------------------------

Router#traceroute 172.16.1.71

Type escape sequence to abort.

Tracing the route to 172.16.1.71

1 ? ? ?

2 ? ? ?

3 * ? ?

4 ? * ?

5 ? ? *

6 ? ? ?

7 * ? ?

8 ? * ?

9 ? ? *

10 ? ? ?

11 * ? ?

12 ? * ?

13 ? ? *

14 ? ? ?

15 * ? ?

16 ? * ?

17 ? ? *

18 ? ? ?

19 * ? ?

20 ? * ?

21 ? ? *

22 ? ? ?

23 * ? ?

24 ? * ?

25 ? ? *

26 ? ? ?

27 * ? ?

28 ? * ?

29 ? ? *

30 ? ? ?

Router#ping 172.16.1.71

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 172.16.1.71, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/1 ms#

-------------------------------

Regards

Leung Che Man

I have this problem too.
0 votes
Correct Answer by Richard Burts about 7 years 3 months ago

Leung Che Man

Given what you have told us I believe that the logical conclusion is that the device is not responding to the traceroute. Perhaps it is running some firewall or has some security settings that will not respond to UDP packets to ports that are not active.

HTH

Rick

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Richard Burts Fri, 09/11/2009 - 03:54

Leung Che Man

My guess is that the next hop toward that destination is a firewall (or some other device that is examining packets and permitting and denying traffic) and that device is not permitting the traceroute (which from a Cisco router are UDP packets to some high number UDP port). That device does allow the ICMP ping to go through.

What is the device at the next hop?

HTH

Rick

cm6043 Fri, 09/11/2009 - 16:14

Hi Rick,

A C2960 switch connect cisco router and this device(172,.16.1.71). I do traceroute from cisco router to this device. By 'sh arp', I can guess this device is a dell server. Does the device not allow to be traceroute ?

Thanks

Leung Che Man

Richard Burts Fri, 09/11/2009 - 17:54

Leung Che Man

If I am understanding correctly your explanation of the topology, then from a layer 3 perspective from the router the device is the next layer 3 hop. If the device is the next layer 3 hop and if traceroute is not working then either the device is not responding as expected or the router is not accepting the response. Is there any kind of access list on the interface of the router?

Can we also verify that the router has a correct route to the device? Can you post the output of show ip route from the router? And perhaps post the output of show arp from the router?

HTH

Rick

cm6043 Sat, 09/12/2009 - 15:55

Hi Rick,

The device and the router are connected to the same cisco switch with same ip subnet. I think the device is not accept the traceroute.

Router#sh arp | inc 172.16.1.71

Internet 172.16.1.71 169 0022.1954.bb4f ARPA GigabitEthernet0/1

Router#sh ip int brie

Interface IP-Address OK? Method Status Prot

ocol

GigabitEthernet0/0 172.16.200.6 YES NVRAM up up

GigabitEthernet0/1 172.16.1.1 YES NVRAM up up

FastEthernet0/1/0 unassigned YES unset up down

FastEthernet0/1/1 unassigned YES unset up down

FastEthernet0/1/2 unassigned YES unset up down

FastEthernet0/1/3 unassigned YES unset up up

Serial0/0/0 172.16.200.2 YES NVRAM up up

Vlan1 unassigned YES NVRAM administratively down down

Vlan111 172.16.2.1 YES NVRAM up up

NVI0 unassigned NO unset up up

Router#

---------------

Thanks

Leung Che Man

Correct Answer
Richard Burts Sun, 09/13/2009 - 13:55

Leung Che Man

Given what you have told us I believe that the logical conclusion is that the device is not responding to the traceroute. Perhaps it is running some firewall or has some security settings that will not respond to UDP packets to ports that are not active.

HTH

Rick

cm6043 Sun, 09/13/2009 - 17:14

Hi Rick,

I think I want to contact the end customer to check the setting this device.

Thanks

Leung Che Man

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