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Any idea why computer IP address would change?

by wgrayson / September 9, 2010 7:56 AM PDT

About 6 or 7 months ago, I successfully set up my home PC (running Windows 7 Pro) to work with Remote Desktop Connection. I figured out all the hard stuff --- how to access it via the router's IP address, how to configure both the router AND the firewall to open the appropriate ports, etc.

My actual PC behind the router and the firewall had an IP address of of something like (this one of the default IP addresses given to a PC as part of a network). This IP address needs to be plugged into the router's settings. While I was away on a trip I was unable to access my PC remotely. When I returned to troubleshoot the issue, I discovered the IP address had changed to (note the last digit change). Ummmmmmmmmm, any idea how an IP address could have changed?

My wife informed me that on one day only she was having connectivity issues with the internet, so I instructed her on resetting both the cable modem and router --- the simple way of unplugging and replugging both. Could this have anything to do with it? RDC is working fine now, but I'm just curious.

Thanks in advance,


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Resetting The Router Did It..
by Grif Thomas Forum moderator / September 9, 2010 9:07 AM PDT

As such, the computer is recognized as if new and a new IP address is released from the router to the computer..

Hope this helps.


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Grif is correct
by lacsr / September 9, 2010 9:16 PM PDT

If the possibility of it getting a different IP address from the router will cause further problems, set up the router is given the computer in question a fixed IP address, instead of auto assigned. Depending on the router, it usually is easy to do.

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by andersonalexer / September 10, 2010 5:18 AM PDT

do you use dhcp server?

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Not sure if I'm using a DHCP server
by wgrayson / September 10, 2010 2:03 PM PDT

I have a typical home office setup with a cable modem provided by my ISP connected to a standard Linksys G router.

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DHCP Servers is the key
by warrencharlot / September 10, 2010 3:33 PM PDT

If you are using third party devices that acts as a DHCP server such as routers then your IP address may change especially when you try to turn it off and on or if you try to change it manually in some cases. Modems are not DHCP servers but some modems are actually modem-routers that is considered a DHCP server. Your phone or ISP server may provide you with a modem without telling you that it is actually a modem-router which changes your IP.

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