1. Click the 'Start' button on the Windows 7 computer desktop and click 'Programs,' then 'Internet Explorer.' Type '1.2.3.4' (all typing done without the quotation marks) into the address bar at the top of Internet Explorer, replacing '1.2.3.4' with the IP address of the Linksys router. Press the 'Enter' key. Type the administrator credentials of the router into the administration page that appears and press the 'Enter' key. Click the 'Security'tab and click 'VPN Passthrough.' Click the 'Enable' radio button in the 'PPTP Passthrough' row and click the 'Save Settings' button.
2. Open 'Internet Explorer' on the Windows 7 computer and type '5.6.7.8' into the address bar at the top of Internet Explorer, substituting the '5.6.7.8' with the IP address of the D-Link router. Press the 'Enter' key. Enter the user name and password of the router administrator account into the Web page that appears and press the 'Enter' key. Click the 'Advanced' tab and click 'Firewall Settings.' Tick the 'Enable PPTP Passthrough' check box so that the box is selected. Click the 'Save Settings' button.

3. Start the 'Internet Explorer' web browser on a Windows 7 computer and type 'a.b.c.d' into the address bar in Internet Explorer but replace 'a.b.c.d' with the IP address of the Netgear router and tap the 'Enter' key. Type the user name and password for the account that has administrator permissions on the router into the Web page that is displayed. Press the 'Enter' key. Click 'WAN Setup' in the left pane and click the 'Enable' radio button in the 'PPTP Passthrough' row. Click the 'Apply' button to save the settings.