This guide assumes you have a Linksys BEFSR41 router. It will be fairly similar if you have another Linksys router like the 'wireless' or 'firewall' (BEFSX41) version but I'm not sure because I don't have these.

I'm running Windows XP Pro, but these instructions work fine with XP Home too. Windows98 users will want to look at the alternate instructions. The first two alternatives describe how to configure the router without using DHCP. Using DHCP sometimes makes things messy but Linksys offers a way to keep DHCP via Port Triggering

The aim of the guide is to show you how to setup your Linksys router so that you can use eMule. There are two ways to do this, either as below using UPnP, or by using a browser. These instructions are long and drawn out on purpose, hopefully so you don't get stuck! Realistically the whole thing is really very easy once you get the hang of it, so please don't be too intimidated by how long these instructions are.

Security Concerns with UPnP There are some serious security issues with Universal Plug and Play. You should read about them here. Thanks to Monk for letting me know about this. To check your security you might want to try some of the tests at http://www.pcflank.com/ or this test at http://www.dslreports.com/scan/ If after reading / testing you decide to go ahead and disable UPnP then you'll need to follow my alternate instructions for setting up port forwarding without UPnP. Or, if you decide that you are perfectly secure then continue below.

Windows XP UPnP instructions

1. The first step is to make sure you have a fairly recent firmware version for your router. Firmware is like the internal software inside the router. You can upgrade to the latest version by visiting the Linksys download page. Select your router from the drop down list, select the firmware link, save the file and follow the instructions. They make it fairly easy and straightforward to do, and it is quick.
   
   
2. Once you've done the previous step... In Windows, click start>settings>control panel>network connections to open this page:
   
   
   
   Compare what you see to my picture, if you have the entry that says Internet Gateway enabled, you already have UPnP installed and this whole process will be easier. Windows XP should have already set all this up if you bought your router and it already had firmware version 1.42 (?) or later installed. If you do anyway then skip ahead to step number 4 below.
   
   
3. To install UPnP:
   
   
   1. Click Start, click Control Panel, and then click Add or Remove Programs.
      
      
   2. In the Add or Remove Programs dialog box, click Add/Remove Windows Components.
      
      
   3. 
      
      In the Windows Components Wizard, click Networking Services, click Details, and then select the 'Universal Plug and Play' check box. You should also see 'Internet Gateway Device Discovery and Control Client' listed, put a tick in the check box for this also - as I've done below.
      
      
      
      
   4. Click OK, and then click Next in the Windows Components Wizard. You may need to provide your Windows XP installation CD.

      
      ( I found this info at http://www.microsoft.com/windowsxp/expertzone/columns/crawford/02july22.asp)

   5. Using your browser, go to http://192.168.1.1/Passwd.htm and, as shown in the picture below, make sure that 'UPnP Services' are enabled:

   
   
   

   6. Click Start>Settings>Network Connections. Right click on 'Local Area Connection'. Select 'Properties'. A small window appears. At the top click on 'Advanced'. Make sure that the XP firewall is turned off as in the picture below:

   

    

   7. Now check back to step 2 above to make sure you have the UPnP working right. It seems to take a while for the internet gateway entry to appear so be patient, wait a couple of minutes perhaps and check again if it isn't showing when you first look, refreshing the window often makes it miraculously appear.

   
   
   

4. Now that you have UPnP up and running setting up port forwarding is really quite simple...
   
   The first thing to do is to highlight the entry for the local area connection in the network connections page just like i'm doing in the picture below:
   
   
   
   On the left side in the details section you should now see your router assigned ip address as shown in the picture below:
   
    ...in this example it is 192.168.1.100, make a mental note of whatever yours happens to be.
   
5. Back on the main section of the page, right click on 'Internet Connection' and then select 'Properties' from the menu that appears.
   
   You'll see this window:
   
   
   Click on settings, and then 'Add'. This is where you will specify which ports the router needs to forward to make eMule work. Fill in the blanks as below, except in the IP address field substitute your own router assigned IP address that you memorized from the previous step. The 'Description of Service' text field can be anything you like - it's just so you can identify it later... "eMule" works just fine:
   
   
   
6. After clicking on 'OK' to save this new setting, click 'Add' once again to setup a second port forward. Once again fill in your own IP address, type "eMule" as the description of service, and copy the remaining details as they are shown below. Then click 'Ok' to save the settings:
   
   
   
7. You'll notice that you now have two entries for eMule, as in the picture below:
   
   
   
   Click 'Ok' to save the settings you made and exit. That's pretty much all there is to it! You've told your router to forward incoming traffic to ports 4662 and 4672 on your computer. Run emule and everything should now work.

Windows98 / Alternate instructions / not using UPnP

1. Open up your web browser and type in the address: http://192.168.1.1 to access your router status pages. Enter your password, the username is an empty field on my machine and it doesn't seem to matter... you HAVE changed the default password right? If not then for your own sake read your linksys manual and do this now!
   
   
2. Click on the DHCP tab at the top
   
   
   
   Then click on the button labelled 'DHCP Clients Table'. You'll see the window below appear:
   
   
   Look in the Client Hostname column, find your computer name and memorize the last three numbers of the IP address to the right of it. In this example the client hostname is 'Christopher', and the last three numbers of the IP address are 100. Once you've got those three numbers memorized then close the window.
   
   
3. At the top of the screen, on the right hand side, click on the orange colored tab labelled 'Advanced'. You'll arrive on the 'filters' page - you don't want to do anything here, instead click on the second tab along labelled 'Forwarding'... and fill out the details as I have below. Except of course you need to fill out the last three numbers of your IP address that you memorized (it might well be 100 like mine is):
   
   
   
   
4. At the bottom click on 'Apply' to save the settings you just typed in. Now your router is setup to forward incoming traffic to ports 4662, and 4672 on your computer. Close out the browser window, and run eMule, it should now work!
   

Configuration with DHCP via Port Triggering