Previous Table of Contents Next You'll also want to keep current on service packs for your operating system. For example, as of this writing, NT Server 4.0 should have Service Pack 3 installed, and Service Pack 4 is just around the corner. In a nutshell, you can overcome Web server reliability problems by exercising the divide-and-conquer practices from Hour 4, "The Napoleon Method: Divide and Conquer," and look up specific error messages by using the techniques from Hour 7, "The Simple Simon Approach: The Benefits of Being Too Stupid to Quit, But Too Smart to Keep Tackling a Complex Problem Head On." Third-Server Problems Even though your Web server is running smoothly and dishing out HTML to beat the band, you still might experience problems with your intranet applications. Intranet applications tend to rely on more than one server, so it's a good idea to have a diagram of how these applications interact with each other. For an example, see Figure 19.7, a diagram of an intranet application called Knowledgenet. See how the Web server itself is just one piece. For the application to work, the remote control "thin client" server must be functioning, and the CD-ROM server must also be functioning. Notice how the CD-ROM server only speaks IPX/SPX and is a Novell server-it's not a TCP/IP server. [19-07t.jpg] Figure 19.7 A sample "thin client" multiprotocol, multiserver intranet. The bottom line is this: Even though your Web server is functioning, any one of the other two components malfunctioning makes the entire intranet application stop working. Again, documentation is key here; if someone tells you that the Knowledgenet application is not working and you pull up this diagram, you naturally know which servers to check. Email Fail? Proprietary email is basically a client/server application or, in some cases, a specialized file-sharing application. When trouble arises with your proprietary email system (such as GroupWise, Lotus Notes, or Exchange), you're best off checking your product documentation and using the file-and-print or client/server troubleshooting techniques we discussed in Hour 18. However, each one of these proprietary email systems also supports Internet/intranet standards and provides gateways to hook up to the Internet at large. Internet (and therefore intranet) email has three components: o SMTP-Simple Mail Transfer Protocol (server-to-server communication) o POP-Post Office Protocol (client-to-server communication) o IMAP-Internet Mail Application Protocol (client-to-server communication) You can telnet to socket 25 to check whether SMTP gateways are up and accepting connections. Here's an example: $ telnet wpo 25 Trying 167.195.160.7... Connected to wpo.co.chatham.ga.us. Escape character is `^]'. 220 wpo.co.chatham.ga.us GroupWise SMTP/MIME Daemon 4.11 Ready 1993, 1996 Novell, Inc. You can also telnet to the POP socket (socket 109 and socket 110, depending on the version of POP that you're using) and the IMAP socket (socket 143) to make sure that the servers that are supposed to be accepting these types of connections are up. Here's an example: $ telnet moria 143 Trying 167.195.160.6... Connected to moria.co.chatham.ga.us. Escape character is `^]'. * OK moria.co.chatham.ga.us IMAP4rev1 v10.170 server ready If you're having trouble getting outside mail from the Internet to your intranet, you'll want to use nslookup to check your MX record for your zone. An MX record is a special record denoting the "mail exchanger" for your zone. Here's an example: $ nslookup > set type=mx > co.chatham.ga.us co.chatham.ga.us preference = 10, mail exchanger = moria.co.chatham.ga.us moria.co.chatham.ga.us internet address = 167.195.160. If it's not the right server or if you don't even have one, you'll need to change this on your DNS server or ask your ISP to do it for you. Dialing Difficulties Do you run into problems with the following types of dialing? o Dialing out of your intranet and into the Internet o Dialing out of your intranet and into somebody else's intranet Huh? Dialing out of your intranet and into the Internet? Even when you have an Internet connection? Don't laugh-it happens more often than you'd think. Either there's a Neanderthal policy handed down from above that the Internet will not be used for personal use or folks just don't feel comfortable using the Internet for non-work-related business. Dialing out of your IP network and into someone else's intranet is also reasonably common. Therefore, let's take a look at the technical implications of dialing out of your IP network and into another IP network (whether the Internet or another intranet), along ______________________________________________________________ You'll want to let users know that they might not be able to get to "local" TCP/IP applications while they're dialed in to another network. ______________________________________________________________ ______________________________________________________________ Microsoft dialup networking will offer to "clear the existing DNS servers." Let your users know that they should not do this; otherwise, they'll be unable to access your local area network services. ______________________________________________________________ with some common problems that folks encounter. Previous Table of Contents Next