LinkSys VPN Routers

LinkSys, now a Cisco company, has a line of low cost routers. I have used the BEFVP-41 for several years as a VPN box to route traffic for parking applications over the internet. These routers seemed to be very stable once they have been setup. LinkSys recently upgraded their 41's to Version 2. I will describe my trials and tribulations in getting these new boxes to work.

The Good

The new versions have simplified and improved the user interface. If you have never configured one of the newer routers, they use a mini-webserver inside the box to allow for configuration of the operating parameters. This allows for great eye-candy which really sells a lot of boxes at trade shows. Typically this translates into a game of hide and seek. The installer doing the seeking and the settings doing the hiding. LinkSys has improved but not solved this problem with Version 2.

The other feature that has been added is the backup and restore feature. This allows you to copy the many settings to a file that can then be saved and shared. This saves a lot of work should you have to replace the router.

The Bad

In setting up my system I found that their new Version 2 Routers were incompatible with our first network boards. Now the original BEFVP41's worked well with our original boards. When LinkSys revised the firmware, they changed something which broke the compatibility. We phased these boards out of production a year ago so that isn't a big issue for our clients. However, the nature of the failure masked this incompatibility. When a laptop was connected on the same side of the router as our boards, everything worked wonderfully. However, any traffic sent over the WAN side of the router couldn't connect.

Masked Trouble can be very difficult to find and requires a lot of thought about your testing process. This thought should produce questions. The questions are then answered by testing. This is in fact what happened, when I asked the question "Can I route traffic between two laptop computers over the WAN port?", the real trouble, BEFVP-41 Version 2, became apparent.

The Ugly

The really nasty "masked trouble" was entirely within the router. In setting up the router we needed to make changes to the network settings, IP addresses, masks, and gateways. After a lot of trouble and gnashing of teeth we discovered that even though the fancy web based interface showed the settings had been modified, they in fact had not changed. We discovered that to reliably set the router up you have to (1) reset to the factory defaults, and (2) lay in all of your new settings. We stumbled upon this bug accidentally, after changing the settings many times (of course we were only changing the settings on the display not the actual router parameters) the router locked up. We were forced to do a hardware reset and lay in our revised settings. These revised settings worked. Then we tried to adjust them without result. A hardware reset to factory defaults and reprogramming the new parameters worked very well.

The final problem was discovered when we thought to set up the router on the bench and take it to the customer's site. Planning ahead is good, right? Not with this router. When we got to the site, the router's WAN port was numb. We could not get any traffic to flow across the WAN port. Following our own advice we did a hardware reset and reprogrammed the router. Everything then worked.

It would seem that the firmware just looks for a change from the factory settings, any subsequent changes are ignored, UGLY, UGLY, UGLY.

The above represents the opinion of George Mallard, P.E.