h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Anyone here familar with Linksys routers?

Reason being I have a bit of a problem. We have a home network consisting of my pc, a downstairs pc and an xbox.

Usually (as the most used one) my PC is assigned the IP address of .100 by the router.

Here is the problem all my applications are allowed on the router and are unblocked at the .100 addresss and I never have any problems say downloading stuff with bittorrent.

However occasionally for whatever reason the router assigns me a different IP and even though it seems to me I put in exactly the same settings into the router for the new IP I always get told I am behind a firewall..

Anyone know what I am doing wrong?

Obviously if I cannot unblock the ports for the new IP then does anyone know how I assign the IP of my pc back to .100 where I *know* the ports are unblocked.

Your router is set to use DHCP, which is a method of assigning IP addresses to computers and network hardware. It doesn't permanently assign them, it just leases them for a period of time. I believe the default is usually 24 hours. If your computer is off, the router will assign the .100 address to another device (such as your other PC or XBox). When your computer is then switched back on it tries to get the .100 address but can't as it's taken by another computer.

To get round the problem, your best bet would be to disable DHCP on the router, and then assign your IP addresses manually to each device in your network.

Next question (and not wanting to come accross as a ocmplete spaz, but....)

How does one do that?


You always seem to be hleping me with these PC problems Croz.

you will need to connect to your router (normally through a web interface nowadays) and stop the DHCP on it, you will then need to enter the network settings of each machine and give them an address manually. Until later...
BCNU - Crescent

Well what I have tried is cfhanging the length of time the router assigns the ip for for from one day to 30 minutes.

When I go home for lunch I will boot up my pc again and if it is given the .100 address I will change the settings back.

My PC is usually on 24/7 but as I went away for the weekend the .100 address obviously went to a different one.

And then of course the flash of inspiration. Just unplug the router so it forgets which pc has been assigned which ip and boot up again.

D'Oh!

This is a crude solution which might work but depends on turning on all your equipment in the right order. A much better solution is to do as I suggested in the other thread - tell the router to assign a particular address to your pc. It'll me in the router control menu somewhere.

It worked perfectly.

I set the router up to only allow one IP, disconnected *everything* form the router. Powered it down then up again and turned on my PC

et Viola.

My PC is .100 again. Hooray!

To assign yourself a static IP address permanantly:
Go to wireless network connection properties. You can get here by right-clicking the wireless network icon in the system tray (bottom right of your screen by default) and left-clicking on properties.

You want to be on the general tab (you will probably start here).
Scroll down to find the entry 'Internet protocol (TCP/IP)'. Left-click on this and then on 'properties'.

Select 'Use the following IP address'.

If you are using the same router as me (Linksys WRT54G I think it is) and you have not changed the following in the router configuration then you want:
IP address: 192.168.1.100
Subnet mask: 255.255.255.0
Default gateway: 192.168.1.1

Select 'use the following DNS server addresses'.
Preferred DNS serve: 192.168.1.1 (same as your router's address).

This setup will cause a conflict when you try to connect and the router has already DHCP'd the address 192.168.1.100 to another device. Either disable DHCP or configure it to assign addresses from 192.168.1.101 You should be able to do this from the very first basic setup screen when you login to the router.

If your router is set up differently to mine with regards the IP addresses then it shouldn't be too hard for your to extrapolate the different numbers I'm sure.

>>It worked perfectly.

But will it work tomorrow when you turn it all on again in a slightly different order? What I was suggesting would solve your problem rather than just working around it.

Yeah well I think it only worked cause I was away for the weekend. Because my PC is on pretty well 24/7, if it retains the ip for 1 day then unless I am away it will never be an issue.