Multi-Homing on the Web

Step 6­ Add a Phone Book entry in RAS. When you install RAS, NT adds a new Program Group, Remote Access Services (Common), to your server's desktop. Locate it, and click the Remote Access icon. You get a message that says the phone book is empty--click OK.

You can now enter specific ISP information such as name, phone number, and description. Click the Network button, and mark the Point-to-Point Protocol (PPP) radio button. Under the PPP setting, mark the TCP/IP box, and click TCP/IP Settings. The PPP TCP/IP Settings dialog will open. Select Require Specific IP Address, and enter the unique IP address for your Web server. This address identifies your Web server as a gateway to the other IP addresses you assigned to each organization.

Select Use specific name server addresses, and type in the IP addresses of the primary and secondary Domain Name System (DNS) servers you plan to use to resolve host names (for information on DNS, see Spyros Sakellariadis, "Configuring and Administering DNS," August 1996, and "Integrating and Administering DNS," page 121). Typically, these servers are at your ISP's site, but they can be on your network. Mark the box, Use default gateway on remote network. Find out whether your ISP supports PPP compression and whether to mark the box, Use VJ header compression.

Step 7­ Add a parameter in the Registry on your NT Web server if this server will route traffic among your Internet connection and other parts of your network. From any window, choose File and Run, type REGEDT32.EXE, and click OK.

This sequence invokes the Registry Editor. Find and click the key hkey_local_machine\system\currentcontrolset\services\rasarp\parameters.

Choose Edit from the pulldown menu, and select Add Value. Type DisableOtherSrcPackets, and click OK to open the DWORD editor dialog. Fill in 0, and click OK. When you finish, the value will be DisableOtherSrcPackets:REG_DWORD:0.

Step 8­ Test the TCP/IP and RAS installation. Dial in to your ISP before you add the Web software.

Step 9­ Install Web server software. Confirm that your installation is working to this point, and look up virtual servers in the manuals for your Web server software. Configure each organization's subdirectory and load all appropriate files, such as home pages, into each subdirectory.

Step 10­ Test all URLs on your server. Using a Web browser, try to access each organization's URL to see whether you can view its home page.

Step 11­ Add organizations as users on the system. You can either let each organization dial in to your Web server to maintain its directory, or you can maintain each directory. NT's security and permissions let you restrict each organization to seeing and editing only its directory.

To let each organization manage its directory, add each organization as a user in the User Manager and give each one rights to its subdirectory. At minimum, let each organization read and write to its directory. Under RAS, choose an organization's user ID and give it permission to dial in to the server.

Tips for Adding Multi-Homing
If you house several organizations' Web services, you need redundancy to eliminate single points of failure. If your server goes down, you kill business for those other organizations until you can repair the problem. Here are some tips to safeguard against common points of failure.

1. Choose your ISP carefully. Select an ISP with two links to the Internet, and check the ISP's references to find out about downtime. To ensure that your Web pages display quickly, choose an ISP with at least a T1 Internet link. A backup link to your ISP's location is also a good idea.
2. Build a fault-tolerant Web server: Spend the money to ensure that you can quickly recover when a component fails on your Web server. You can mirror the disk drives and use hot-swappable components. Back up data daily, and frequently store backups off site.
3. Have a regular maintenance plan: Don't run out of disk. Perform maintenance daily, and watch for server trends. Install software that automates maintenance and monitoring and that pages you when problems arise.
4. Have a security plan: Check logs for odd nuances relating to security. If hackers access your system, they can also access data you're housing for other organizations. Carefully read the security information that comes with your Web server software.
5. Have a disaster-recovery plan: Be able to move your shop to a new location and be up and running in a short time (for more on disaster planning, see Valda Hilley and Sean K. Daily, "Attaining Availability; Avoiding Failure," August 1996). If you're housing other organizations' data, don't take your responsibility lightly.
6. Implement reverse DNS: Some Web servers rely on reverse DNS lookups to perform virtual Web services for domains. However, not every Web server uses reverse DNS, so check with your vendor and make sure that if you use your ISP's DNS, reverse pointer records are available for you.