Documentation for WinProxy

DNS/Socks

Overview: DNS/Socks

If you're satisfied with your basic browsing and mail features, you can skip this chapter. However, more and more services on the Internet seem to need DNS to operate. If you'd like full Internet functionality, adding DNS to your network setup, read on.

The Domain Name System (DNS) is used in conjunction with IP addressing to map computer names to IP addresses. Basically, DNS is just another way to navigate a network. The Internet addresses you're used to seeing-WinProxy.com, for instance-are part of the Domain Name System. Just as the Internet uses DNS to help people and applications find their way around the global network, you can use DNS to help your applications find their way around your local network.

Many applications, both large and small, require DNS in order to work. Among them are Java applets, the Socks Protocol and the AOL protocol within WinProxy. You may not be familiar with the Socks protocol yet, but you'll see it more often as you become conversant with networking. The flexible and powerful Socks protocol is becoming a popular choice among programmers when adding proxy support to applications.

A NOTE OF CAUTION:The very flexibility and power that Socks provides also makes it a bit more of a security risk than other protocols. If your local network hosts extremely sensitive material, think twice before allowing the Socks protocol.

Setting up DNS on your local network

In the example given below, (1) WinProxy is used as the DNS server on your local network; and, (2) each computer on the network is set up to be a DNS client. Although the instructions indicate click-paths used in Windows 95/98/NT/2000/Me/XP setup is similar. Screenshots of all settings for Windows 95/98 and NT are on our website.

Setting Up the Server Machine

To begin, you'll need the IP address(es) of your ISP's Domain Name Servers. These addresses are usually listed on the ISP paperwork (often as "primary" and "secondary" servers). If necessary, WinProxy can obtain them for you. Here's how:

• From the Settings Tab, click Protocols/DNS Set-Up/Find My Name Server.
• Follow the formatting instructions, clicking on Find my DNS Server.
• WinProxy brings up your default browser, using the information you provided to find your ISP's listing with InterNIC. Part of that listing includes the IP addresses of your ISP's DNS servers.

Once you have the appropriate IP addressing information, you can proceed. The first step is to set up the WinProxy machine as your DNS server:

• In WinProxy, click File/Settings/Protocols.
• Check the box beside DNS Set-up, enabling DNS.
• If you intend to use Socks, put a check in the appropriate box.
• Click DNS Set-Up.
• Look in the Current DNS Server List to see if your ISP's primary DNS server is already listed (it might have been added during the original setup). If not, enter the address in the DNS Server IP to add box and click Add to include it in the Server List.
• Using the same procedure, add the secondary DNS server IP. If you weren't given one by your ISP, just leave this line blank; the secondary is used only when the first fails to respond.
• Enter a name in the Domain box where the instructions ask for your local domain name. You can use your ISP's domain here, but it's better to use your own. Feel free to make one up: fred.com or suzie.org will work just fine. The name doesn't need to be officially listed with any Internet bodies-since it's on your local, pri vate network, it's invisible to the rest of the world. All of your computers should have the same domain name, and because of the way DNS lookups are made it's best if you have a .com or other standard domain name on the end.
• Click Namelist and follow the directions to make a local name list for your DNS server-that is, a list of all local computer names and the IP address for each. Using this list speeds up local lookups. If you don't know a computer's name you can find it at Settings/Control Panel/ Network/Identification/Computer Name. You can change that name whenever you want, but remember to also change it in the namelist.

Finally, click OK buttons until you've returned to WinProxy's Main Screen. You should see a small dialog box telling you that settings are being updated. You won't need to restart WinProxy for the settings to take effect. WinProxy is now configured as your DNS server.

Setting Up the DNS Client on the WinProxy Machine

One of WinProxy's benefits is that it doesn't need to run on a "dedicated" computer (a computer with only one function). In other words, when a computer becomes a WinProxy server, it continues running all the applications it ran before with no changes whatsoever. Further, the WinProxy server can also be a client-just like all the other PCs on the network, it can access the Internet through WinProxy.

For this reason, the WinProxy computer is configured with both server and client settings. Now that the computer is established as a DNS Server, you'll set it up to also be a DNS client. Doing so allows applications on this machine to work with your ISP's DNS server if you happen to use them while WinProxy isn't running. And don't worry: you'll experience no conflict with client/server settings, since they're entered in different locations

• On the WinProxy machine, go to Control Panel and then choose Networks/Identification/Computer Name. Write down the name you see listed for the computer (you'll use it in a moment).
• Click the Configuration Tab.
• Double-click on the TCP/IP protocol line for the local (LAN) adapter.
• Click the DNS Configuration Tab and then Enable DNS.
• Under Host, type in the computer's name. Under Domain, enter the same name you used when setting up WinProxy. In the DNS Server Search Order box enter the IP address of the WinProxy machine itself (i.e., 90.0.0.1) and then the same ISP DNS addresses you entered in WinProxy.

The WinProxy machine is now set up as a DNS client machine. Let's proceed to setting up DNS on the other computers in your network.

Setting Up Your Other Machines as DNS Clients

If your client computer/s have the default settings-i.e., TCP/IP has been set to "Obtain Automatically" and DNS to "Disable"-you needn't enter DNS information. WinProxy's DHCP server automatically supplies all necessary DNS information for you.

(By way of explanation, the "Disable" setting is something of a misnomer, since in practice it really means the same "Obtain automatically").

However, if you're not using the default settings, let's proceed with setting up your DNS clients. For each machine on your local network:

• In the Control Panel, double-click Networks and then Identification. Double-check the individual computer name-you'll be using it in the next step.
• Double-click the TCP/IP protocol line for the local (LAN adapter.
• Click the DNS Configuration Tab and then Enable DNS. Under Host, enter the computer name obtained in the previous step.
• Under Domain, enter the same domain name used on the WinProxy machine.
• In the DNS Server Search Order box, enter the IP address of the WinProxy machine (e.g., 90.0.0.1).
• Click OK until you return to the Main Screen. Windows should inform you that you must restart the computer for the settings to take effect.

Your entire local system is now configured to use DNS in its network activities. If you plan on using the Socks protocol (most people will) or the AOL protocol, make sure that those protocols are enabled within WinProxy (you can do so at Settings/Protocols).

Testing Your DNS Setup

You might want to check and see that your local DNS search is working properly. You can use Ping for this, though in a slightly different format than we used before. Make sure WinProxy is running and connected to your Service Provider, and use Ping with domain names instead of IP addresses:

Figure 2.1: Testing your DNS setup with ping

All three of the Ping attempts shown here were done on a client computer behind WinProxy.

The first example is ping winproxy. It gives the results shown if you have configured the client computer and the WinProxy computer for DNS. This test works whether or not you're connected to the ISP. Test each client computer this way. You'll notice that the ping command is concatenated with the local domain name, in this case Ositis.com. The IP address shown, 90.0.0.11, was the IP address of our office WinProxy machine at the time we tested. This test confirms that your local DNS setup is working, at least on the WinProxy and client machines used.

The second test shown, ping yahoo, illustrates the result to be expected when you've specified a bad domain name, or when DNS can't resolve the name.

The expected results of the third test will vary depending on the WinProxy version you're running. We'll cover WinProxy 2.1 first, as shown in Figure 2.1. You may think things aren't working when you first glance at the third test, ping yahoo.com. But the results actually confirm that the DNS lookups are functioning just fine. Though it says Destination Host Unreachable, a close look reveals that it also returned the IP address of yahoo.com. Ping itself won't work through WinProxy 2.1, but the DNS lookup was correctly handled: the local client asked the WinProxy machine, WinProxy asked your ISP's DNS server (which may have known the address or may have asked another DNS server on the Internet for it), and the result was passed all the way back to the client machine. This last test, then, confirms that the chain of DNS lookups is complete from the client machine to the Internet.

With WinProxy 3.0 and above, the DNS portion of the third test works just the same-you ping a name and DNS returns (as part of the message) the IP address to which the name resolved. The one big difference is that Win-Proxy 3.0 and above will allow client machines to ping computers outside the firewall. Instead of "Destination Host Unreachable," you'll see "Reply from...." when pinging through WinProxy 3.0 and above.

Adding the Socks protocol to your browsers

Adding Socks is only necessary for browsers operating through Cproxy. Otherwi Adding Socks is only necessary for browsers operating through Cproxy. Otherwise, don't bother with it. Just as other browser protocols such as HTTP and FTP work without configuration within the WinProxy default, so too does Socks.

But if you need to add Socks it's easy to do so. Here's how:

• In WinProxy, click through the path File/Settings/Protocols.
• Enable Socks, and enter in the Socks box the IP address of the WinProxy computer.
• Set the port to 1080.
• Blank the entry for FTP so the browser uses Socks for FTP connections. This prevents the occasional problems that may result when both are checked. Also, transfers are usually more robust when using the Socks protocol.

The two major browsers treat the other protocols a bit differently when Socks is enabled. Netscape preferentially uses Socks for everything, including mail, and also for unconfigured protocols such as Gopher or WAIS. Internet Explorer uses Socks for protocols that aren't otherwise enabled, like Gopher.

Enabling Other Socks-Based Applications

Many newer Internet-capable applications-especially chat programs and some games-use Socks to support operation behind a proxy. The number or type of applications using the Socks protocol will likely increase rapidly. Technical Support at the Ositis website (www.WinProxy.com) contains screens for a few such common applications configured to run through WinProxy.

The general rule for enabling these applications is to look for a configuration tab or setting about connections, firewalls, or proxies. Once there, check the box that says Socks or Socks 5. WinProxy supports both Socks 4 and Socks 5, but if the application gives you a choice, choose Socks 5. Under Server IP enter the IP address of your WinProxy machine. Under "port" choose the standard Socks port 1080.