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I have 3 desktops all running Windows XP SP 3 connected to a ADSL Modem-Router. On 2 systems I have assigned static IP addresses and am not facing problems with Internet connection or LAN sharing. On the third system, if I assign static IP address then I am not able to visit ALL web sites. In particular I am unable to access an essential business portal. But if I use dynamic IP, then I am able to access all web sites required. But the problem with dynamic IP address is, I lose connection randomly (I get Limited or no connectivity error). I have to disable and enable my network adaptor to regain connectivity. Some times I have to repeat the procedure a few times or restart the system. I even tried to use a LAN card in place of the onboard LAN, but the problem continues. Some times I do not face any problem for 2 - 3 days and then suddenly, it surfaces. There are no proxy settings and I have tried different browsers like Firefox, Chrome, IE 8 etc. I am also using McAfee Security-as-a-Service.

Any suggestions?? Please do not suggest to upgrade the OS as my business software is not fully compatible to other versions of Windows as yet.

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Please give more info. Why are you "not able to visit ALL web sites"? Is there a specific error? Also, what is the static IP you are assigning? Have you tried one of the known working static IP Addr's from the other 2 XPs? – Spencer5051 Jul 25 '13 at 0:59
I get a generic error like web page not found or web site not available (can not recall the exact error message). I tried to assign IP in the range of And no, I didn't thought about using a working static IP from the other systems. Thanks for the idea. Will see if it works. – LalitBarik Jul 25 '13 at 1:56

1 Answer 1

What is the lease time on your DHCP addresses supplied by the router? I have had issues with Windows machines dropping connections if you're using the network across a lease expiration. Some home routers default to 1 hour or several hours, most seem to have 24 hours as their defaults. Even a staticly assigned dhcp address is vulnerable. This would explain why your two static IP addressed machines are stable, while the dhcp machine is flaky.

If you can, set the third machine to a static IP, OR change the lease time to a week or more (604800 seconds = 7 days).

Oh, and if you try the "0 = infinite lease" on the router with a windows machine, I can almost guarantee issues, since windows doesn't parse the given value (-1 = 0xFFFFFFFF) properly, it actually ADDS the current time to the lease time (in seconds)... but doesn't check for the special '-1' infinite value. So the expiration is one second in the past, causing windows to re-request the lease. Stupid Windows! Standards are for Following!

It also seems that during the lease renewal, windows (at least XP) disconnects/drops the address during the renewal request, making all the connections drop too. Booo! Where did you want to go today?

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Sorry for the delay in replying here. I switched the LAN cable, LAN port or the modem-cum-router as well as the IP address of a working system. And it did the trick! Even though I am not sure why the problem arose at the first place, I am happy that it seems to have resolved. Thanks everybody for their suggestions and help. – LalitBarik Aug 7 '13 at 22:19

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