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Linux: A Network Solution for Your Office ContentsIndex Chapter 12: Using External Routers: Summary Previous ChapterNext Chapter Sections in this Chapter: Routing Revisited lSummary Special Router Devices Manual Pages Previous SectionNext Section Summary Although a Linux server makes an excellent router, sometimes it is necessary to use an external routing device. Typically this occurs because you use a dedicated router for high-speed Internet connections. In this case, even if you continue using the Linux host as a server, routing and other server functions become separated, and the system and your network must be configured accordingly. Sometimes, an external router is used in combination with a segmented network. In this case the Linux server can be retained as a router between the two segments, while the outer segment is routed to the Internet via the dedicated device. This configuration is often used when the Linux server is configured with firewall gateway functionality. When an external router is used, the network needs to be reconfigured. This is especially true if a segmented network is created, because new routing rules must be added. The most frequently used external router devices in small office or home office environments are ISDN routers and cable modems. Configuring ISDN modems is fairly straightforward if you have the requisite information from your telephone company (which installed the ISDN telephone line) and your ISP. Cable modems, however, deserve special attention, because many of these devices represent a serious security risk. To prevent a cable modem from reflecting confidential traffic from your LAN to the local cable loop (and consequently, to your neighbors) it is best to isolate the cable modem from your LAN using a segmented network technique. Linux can serve you well as a router between your internal network and the cable modem. In addition, the firewall capabilities of a Linux server not only enhance your network's security, but also allow you to access the Internet from multiple hosts using a single IP number assigned to you by the cable company. Linux: A Network Solution for Your Office ContentsIndex Chapter 12: Using External Routers: Summary Previous ChapterNext Chapter Sections in this Chapter: Routing Revisited lSummary Special Router Devices Manual Pages Previous SectionNext Section © Copyright Macmillan USA. All rights reserved. |