Traceroute returning same destination multiple times

Posted on 2006-10-28
Medium Priority
Last Modified: 2008-08-14
Trying to get some clarification, I've tried other sources but no real answer. I'm performing a traceroute to a device with a NAT'd address that is connected via VPN Tunnel, for each device that is hidden, I am recieving the destination IP. Is this normal behaviour or is there something wrong. Could this affect performance between the two devices?

Tracing route to over a maximum of 30 hops

  1     6 ms     6 ms     6 ms
  2     7 ms     8 ms     7 ms
  3     8 ms     7 ms     7 ms
  4    14 ms    11 ms    11 ms
  5    15 ms    10 ms    11 ms
  6    12 ms    11 ms    11 ms
  7    11 ms    10 ms    11 ms
  8    12 ms    11 ms    11 ms
  9   144 ms    12 ms    11 ms
 10    13 ms    11 ms    11 ms
 11    12 ms    11 ms    12 ms

Trace complete.
Question by:cfbros
LVL 79

Expert Comment

ID: 17826296
How many hops to you expect to see? If going through a VPN tunnel, I would not expect to see more than 2.
It appears to be a routing loop, but I would not expect to see the actual destination IP as the responder if it was..
Can you explain your topology a little more? Perhaps a little ascii drawing?

Author Comment

ID: 17826370
The number of hops is correct, it is the destination response that i am concerned about. Also, after the response, the rest is on the recipients end and I do not know what the topology is. They claim that this is what I'm suppose to be seeing but I have concerns when I see the destination address responding for each device.
LVL 16

Expert Comment

ID: 17826536
Umm, why can't it just be as simple as "They are NATting their replies to you so you specifically don't see any of their topology"?

What exactly is the problem (what does not work)?

Free Tool: Path Explorer

An intuitive utility to help find the CSS path to UI elements on a webpage. These paths are used frequently in a variety of front-end development and QA automation tasks.

One of a set of tools we're offering as a way of saying thank you for being a part of the community.

LVL 57

Expert Comment

ID: 17826609
The--Captain hit the nail on the head.  The 5th hop is the 1st point within the 'real' network and they are replacing the source IP addresss on the ICMP (ping) messages so that you can't map out the internal network.

Author Comment

ID: 17826719
That I understand, but the question that I'm asking is, should the devices all respond with the NAT'd address?
LVL 16

Accepted Solution

The--Captain earned 2000 total points
ID: 17827327
>should the devices all respond with the NAT'd address?

No.  Assuming this is what's going on, the NAT box lies to you when it sees IPs that match the NAT rules - that's the whole point.


Featured Post

The 14th Annual Expert Award Winners

The results are in! Meet the top members of our 2017 Expert Awards. Congratulations to all who qualified!

Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.

Join & Write a Comment

This article explains the fundamentals of industrial networking which ultimately is the backbone network which is providing communications for process devices like robots and other not so interesting stuff.
In this article, the configuration steps in Zabbix to monitor devices via SNMP will be discussed with some real examples on Cisco Router/Switch, Catalyst Switch, NAS Synology device.
After creating this article (http://www.experts-exchange.com/articles/23699/Setup-Mikrotik-routers-with-OSPF.html), I decided to make a video (no audio) to show you how to configure the routers and run some trace routes and pings between the 7 sites…
Here's a very brief overview of the methods PRTG Network Monitor (https://www.paessler.com/prtg) offers for monitoring bandwidth, to help you decide which methods you´d like to investigate in more detail.  The methods are covered in more detail in o…

627 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question