Re: ICMP type:3, code:3, Destination port unreachable

This might have something to do with traceroute using udp instead of icmp.... And that when that last udp packet arrives at the destination end point, that packet thus ascends the protocol stack , arriving at the udp layer and determines that the chosen udp port number is in fact not open (listening) .... Hence icmp type 3 code 3 is returned to the source telling it that destination port is unreachable .... As I recall nix and IOS use udp ( maybe some high port number like 40000 ) for traceroute and windows actually uses icmp

Aaron

On Mar 27, 2011, at 7:00 PM, Malik Nouman Ahmad <djmalik_at_gmail.com> wrote:

> Hi guys,
>
> I have built a network on GNS3 and have simulated PC using VPCS (
> http://www.freecode.com.cn/doku.php?id=wiki:vpcs).
>
> While doing a traceroute I have got the following output:
>
> VPCS[2]> tracert 23.23.23.1
> traceroute to 23.23.23.1, 64 hops max, press Ctrl+C to stop
> 1 10.177.160.2 63.000 ms 47.000 ms 46.000 ms
> 2 10.177.162.9 218.000 ms 94.000 ms 78.000 ms
> 3 10.177.162.2 171.000 ms 125.000 ms 110.000 ms
> 4 62.190.99.1 156.000 ms 156.000 ms 156.000 ms
> 5 *144.123.20.9 265.000 ms (ICMP type:3, code:3, Destination port
> unreachable)
>
> The trace is correct and the IP address (23.23.23.1/24) is in fact a
> loopback on the same router which is on hop 5.
>
> I am trying to understand as to why I am getting "Destination port
> unreachable" and how can it be fixed
>
> Regards,
> Malik
>
>
> Blogs and organic groups at http://www.ccie.net
>
> _______________________________________________________________________
> Subscription information may be found at:
> http://www.groupstudy.com/list/CCIELab.html

Blogs and organic groups at http://www.ccie.net
Received on Sun Mar 27 2011 - 19:13:28 ART