No internet access - destination port unreachable

[Adam Thompson]

HI all,

Getting a strange problem here. Got about 120 computers, all from the
same unattended windows build, all picking up IP configuation from the
same DHCP range, and one of them, is giving 'destination port
unreachable' errors when trying to ping external addresses, either by
name or IP.

The machine can't see anything external to the company network (using
anything - have tried ping, IE6, telnet.exe), and I don't know why.

I've disabled NetBIOS over TCP/IP, I've removed the connection on the
XP machine, removed the adapter in device manager, re-installed the lot
and the same thing happens.

Any pointers would be most gratefully appreciated, as I'm out of ideas.

 

[Robert L [MVP - Networking]]

Use tracert command to trace where the traffic to. Or these search results may help,

troubleshooting ping issues ping 4.2.2.1 Pinging 4.2.2.1 with 32 bytes of data: Reply from 209.165.105.129: Destination net unreachable. Causes: If you have incorrect IPSec settings, ...
www.chicagotech.net/troubleshootingping.htm


routing issues on vpn TTL expired in transit and Destination host unreachable. Can ping VPN server only but not other resources. Symptom: after establishing VPN, you can ping and ...
www.chicagotech.net/routingissuesonvpn.htm



Bob Lin, MS-MVP, MCSE & CNE
Networking, Internet, Routing, VPN Troubleshooting on http://www.ChicagoTech.net
How to Setup Windows, Network, VPN & Remote Access on http://www.HowToNetworking.com
HI all,

Getting a strange problem here. Got about 120 computers, all from the
same unattended windows build, all picking up IP configuation from the
same DHCP range, and one of them, is giving 'destination port
unreachable' errors when trying to ping external addresses, either by
name or IP.

The machine can't see anything external to the company network (using
anything - have tried ping, IE6, telnet.exe), and I don't know why.

I've disabled NetBIOS over TCP/IP, I've removed the connection on the
XP machine, removed the adapter in device manager, re-installed the lot
and the same thing happens.

Any pointers would be most gratefully appreciated, as I'm out of ideas.

 

[Adam Thompson]

Thanks for the suggestions, but neither seem to be applicable, as this
connection doesn't use IPSec or any kind of VPN connection.

 

[Adam Thompson]

Adam Thompson wrote:


Very odd this - still not entirely sure why it happened in the first
place. I set off another build on the PC, so the whole disk would have
been wiped, Windows re-installed, and the apps would have been
re-deployed either by GP or Altiris.
I logged on for the first time, and the same thing was happening again!

I compared routing tables, and saw one entry was different, and sure
enough, traces to the outside world were taking a different path.

The IP was assigned by DHCP (same server and scope as all the other
working machines). I released the IP of the machine (which was
presumably the same again, since the MAC address wouldn't have
changed), and checked on the server that nothing was leased to that
machine. Rebooted the machine, it picked up its IP configuration from
the DHCP server again, and everything worked.

Still scratching my head, but at least it's fixed.

Thanks for the suggestions,


Adam.