How To Allow VPN Through Router


If you have a Virtual Private Network, otherwise known as a VPN, you can connect two secure networks over the Internet.  When you have this type of network setup you will need special software programs and special equipment to connect to the Internet either at home or in your office.  If you are already connected to a VPN and you are trying to find out how to allow VPN through router, you have come to the right place.  When you have a router with “VPN passthrough” capabilities, the router will allow traffic to “passthrough” the endpoints but the router does not necessarily support one of the endpoints in the network.  Find out what you need to do to when your VPN stops working after your install your VPN passthrough router by reading below.

Common Problems with Routers and VPN Networks

If you are not a computer genius, you may not understand why installing your router will cause problems with your VPN network.  When you purchase the router, the main reason you purchase the model you have chosen is because it says that it will work for VPN passthrough with absolutely no modifications.  Just because a product is advertised to be easy to use does not necessarily mean you will never run into problems when you install the router and are trying to allow the VPN to passthrough.  If you find that your network has stopped working entirely because of the setup of the router you should use these troubleshooting tips so you can identify the problem, localize it, and then take the proper steps to fix the problem.


Steps for Troubleshooting

1.  Turn on NAT Traversal.  Not all routers support NAT-T but when yours does it must be turned on to work with VPN passthroughs.

2.  You may need to review the manual of your router or call the network administrator so you can find out how you need to configure your VPN software.  Many times, the router is not the problem.  VPN software must also be configured properly to work with the router.

3.  If you are using an L2TP passthrough you will need to register the MAC address of your router with the system administrator to allow the VPN to function properly.

4.  You may need to check for updated firmware for the router.  If there are firmware updates, make sure to download and install them and it may fix the problem.

5.  You need to turn port forwarding for the right VPN ports (50, 51, and 500 for IPsec).  Make sure to turn on port 1723 for PPTP control.  For routing and remote access, turn on port 1701.

6.  Make sure your firewall is not set to drop ICMP packets that are sent from outside of your network to your WAN port.  Your VPN may require these packets that are being dropped.  Make sure to select Respond to Ping on Internet Port in your WAN Setup and this should solve the problem.

Now that you know how to allow VPN through router, set up your equipment, configure your VPN software, and customize the settings on the router so traffic can passthrough without any problems.

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