TimeStep VPN emphasizes security

Government agencies are interested in virtual private network (VPN) technology because it promises low-cost, secure data transmission via the Internet and can be used to replace long-distance telephone charges and dedicated lines. As part of our continuing coverage of VPNs, we evaluated TimeStep Corp.'s Permit Enterprise VPN and found it to be a secure solution for supporting telecommuters and mobile users.

We recently tested four VPN solutions that used the Point-to-Point Tunneling Protocol [Government Best Buys, Sept. 7]. TimeStep's Permit VPN solution, on the other hand, is based on Internet Protocol Security (IPsec), which provides added security features. In our tests, we found that TimeStep's implementation of the IPsec protocol offers strong security and good performance. In fact, we believe IPsec has a good chance of becoming the dominant IP-based VPN standard.

TimeStep is one of the earliest VPN solutions based on IPsec. Federal customers include the Agriculture Department and the Air Force's Information Warfare Center. Agencies can find TimeStep's Permit VPN on the National Institutes of Health's ImageWorld contract as well as NASA's Scientific and Engineering Workstation Procurement II.

IPsec includes such security measures as authentication, encryption and key management. These measures are designed to beef up inherent weaknesses in IP, which enables such security breaches as World Wide Web spoofing, sniffing and session stealing.

To measure the performance of the Permit VPN, we ran a series of download and upload tests using a single remote client computer that established a secure tunnel via a dial-up connection (see test results chart). While these tests do not reveal the maximum system performance achievable, they are a good gauge of how traffic will flow in the real world. The Permit VPN did well in our performance tests, and we think agencies looking to adopt VPNs should take a close look at TimeStep's offering.

For our evaluation, we first set up the Permit/Gate hardware, which is a bit smaller than a laptop computer. It came with two 10Base-T local-area network interfaces: one connected to our private network and the other connected to the Internet.

To set up communications between the gateway and our management console, we ran a Telnet session from our workstation. Using a basic menu system, we were able to quickly access the configuration screens. The installation process was well-documented and easy to perform.

Next, we set up a management console running TimeStep's Permit/Config software. This software provides a graphical user interface to gain access to the gateway's configuration menus over the network. Permit/Config is a handy utility, especially for managing multiple gateways in a geographically dispersed agency.

For the remote PC, we set up the client software, Permit/Client. This software runs on multiple platforms including Microsoft Corp.'s Windows 95 and 98, Windows NT and Apple Computer Inc.'s Macintosh operating systems. Handy installation wizards allowed us to complete the client software setup quickly. After rebooting the computer, we configured the connection profile parameters, enabling us to set up a secure tunnel over the Internet back to the gateway running in the FCW Test Center.

We used TimeStep's shared secret authentication scheme in our tests, but the company also provides an authentication-with-certificates option. Shared secret is simpler to implement, but TimeStep recommends using certificates in large implementations where layered security is critical. Setting up shared secrets was as easy as creating passwords.

To complete the VPN setup, we had to configure two files: the security-level definitions and the secure network map files. The security-level definitions contain parameters on the types of authentication and encryption schemes that will be employed. The secure network map file specifies which gateway is responsible for which remote VPN node. We created the secure network map file using Permit/Config.

TimeStep's VPN offering supports a number of authentication schemes, such as Handshake Message Authentication Code, RSA Data Security Inc.'s public-key cryptosystem, Message Digest 5, Secure Hash Algorithm 1 and shared secret. Encryption technologies supported include Data Encryption Standard, Triple DES, International Data Encryption Algorithm, Blowfish, RSA's RC5 and Entrust Technologies Ltd.'s CAST. TimeStep uses the Internet Security Association and Key Management Protocol/Oakley and Diffie-Hellman for key management and exchange algorithms. In addition, TimeStep supports public- key infrastructure standards and certificates using Entrust's Certificate Authority. We configured our test unit to use shared secret authentication and DES encryption.

Permit/Client supports Ethernet virtual tunneling, which enables remote computers to establish high-speed tunnel connections using technologies such as Integrated Services Digital Network, xDSL and cable modem. TimeStep recently announced Permit/Client support for token-ring networks.

In terms of network and system management, TimeStep provides event logs to track and monitor activity on the gateway and client computers. In addition, all event logs generated by the Permit/Gate are forwarded to a central syslog server. To ease client administration, the gateway dynamically sends IP address, subnet mask, Domain Naming System and Windows Internet Naming Service information to the Permit/Client.