Letting The Telecommuters Into The Network
- Dec 23, 2004
Locking down the network and patrolling the perimeter is a never-ending job. Still, it feels good to get through another shift on the Forbidden Planet without an invisible force penetrating your shield and setting off alarms. But there's a change: now, other humans want to work from their home worlds -- but by mind alone, over the computer screen. It's up to you to create for them a safe passage (one that won't have Robby the Robot all stirred up and carrying Anne Francis around like a rag doll) and to make sure the Krell don't come sneaking in, under the fence, behind the newcomers.
In other words, you need to let the right people into your network -- telecommuters and other people working remotely -- while continuing to protect the company from criminals. What to do?
The Number One Answer: A Sit-Down VPN
The answer that helps administrators sleep most securely is a fixed Virtual Private Network (VPN). A VPN uses end-to-end encryption to carve out a private tunnel over the public network.
The most secure VPN is the traditional arrangement with the telecommuter coming from a fixed site, ideally using a managed, corporate device, and terminating in a secure, private network on either side. Quite a bit of effort can go into setting up this arrangement; you need to see that hardware, software, and settings, as well as authentication, are set up perfectly and maintained on both ends, despite user changes to software, firmware, and hardware, but the security can be worth the trouble.
Don't let this next bit scare you away: After the act with all the acronyms, you'll have the secret of the monster sneaking past the alarms, and everything lightens up.
Let's throw out some protocols -- literally. There are three or four at this end of the pool. Only one from this group is secure enough to take seriously: IPSec, especially in conjunction with L2TP.
Sit-Down VPNs: IPSec
IPSec is the standard to buy; it encrypts at the packet level. PPTP has weak encryption keys, weak password hashing, and unauthenticated control traffic. L2TP traffic can be read by network sniffers, however, combined with IPSec for encryption, L2TP becomes unreadable, and offers IPSec authenticated access for multiple protocols. Just be sure the device you buy supports the combined IPSec and L2TP standard.
For more on planning and troubleshooting a hardcore VPN -- the kind with special rigging on both ends -- take a look at two additional articles: Introductory VPNs: Mapping LANs and Lines for Fewer Landmines, and VPNs: Dial 'T' for Troubleshooting. (You didn't think we were going to spoil the secret of the monster from "Forbidden Planet," did you? No -- it's only the remote access that gets easier from here on out.)