Wireless Servers: From LANs to the Internet Page 3
By Karl Magsig
It is also true some software packages perform better in a wireless environment. Proxy servers and e-mail servers are examples of servers that may require additional functionality to optimize the performance of a Wireless LAN.
With the emergence of the Internet, an increasing number of wireless networks are being hooked up to shared Internet connections. Today, one of the least expensive and easiest methods of Internet sharing is the proxy server. Many proxy servers support wireless LAN connections as easily as they support wired LAN connections. Some examples are WinGate by Deerfield.com, WinProxy by Ositis software, MidPoint by MidPoint Software, SyGate by Sybergen, NetcPlus Internet Solutions' BrowseGate, and Microsoft's ICS.
Most of these proxy servers also have NAT services available, making any proxy configurations on the workstations unnecessary. In turn, this makes mobile workstations easier to work with. Two of these, Microsoft ICS and WinGate, also provide multiple segmented LAN bridging capabilities. This means clients on a wired LAN can directly share resources with clients on a wireless LAN. Without a network bridge, it is impossible to access shared resources from one network topology to another. Network bridging enables the two separate physical networks to function as one.
Corporate mail servers are another area of growing interest for enterprises with a wireless LAN. Most mail servers allow for both internal (LAN) and external (Internet) e-mail capabilities. To perform optimally, the server may require some extra features. Offered by MDaemon from Deerfield.com and Mercur from Atrium, among others, Short Message Service (SMS) gateway support allows e-mail to be routed from the server to a cell phone or pager. SMS is most common in Europe and is a nice feature for mobile workers.
Since wireless networks are still susceptible to interruption and are still less stable than wired networks, it is also important the mail server include "Keep Alive" packet functionality. These packets enable the mail server to monitor the status of open connections. If the connection is dropped, the mail server detects the disconnection and closes immediately, instead of waiting for the connection to time out. Without this feature, the connection may stay open until the mail server times out due to inactivity, usually around 10 minutes. An unused, open connection may cause slower mail delivery, and possibly disrupt the wireless mail stream.