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one machine on the domain has had the same static internal ip a long time, serving a couple small sites. All of a sudden internet connectivity is not available, although the LAN is. Switching to dhcp gets a new dynamic address which then works. Assigning that new ip as static continues to work, but trying to use the old static ip fails.

What should I look for as a cause? Windows updates have occurred, but nothing else that I see is changed at all in the firewall or in any configuration I have done.

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You got some chaos in your setup. You're using static ip in DHCP subnet which can cause conflicts since dhcp may assign same ip address that you are having as static.

Can you try pinging the old static IP? maybe some device is using it and you get ip conflict although it should be 'announced' by system. Also can you run Colasoft MAC Scanner (free version) and see if you have any device taking your ip?

Also make sure you can ping/access dns when having static ip.

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the static ip was reserved a for this machine and excluded from distribution in dhcp. there is nothing else on that ip. I can ping the internal dns which resolves names for all othe machines fine. I can not ping however so am blocked on this side of the router i guess. – datatoo Jun 25 '10 at 21:57

When you have the original static IP assigned to your server I would try:

  1. ping
  2. ping the static IP (from the machine itself)
  3. ping the default gateway
  4. run a tracert to the other side of the gateway (maybe the gateway's default gateway)
  5. run a tracert to the internet IP
  6. ping the name servers
  7. ping the internet IP (enable ICHP traffic to IP on firewall / router)

I'm guessing your tracert will fail, which means your router is blocking access to / from the internet.

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Thank you, this is exactly the case. I am puzzled what has changed to cause anything being blocked, if you have any ideas. – datatoo Jun 25 '10 at 21:53

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