IIS6 stops working for no good reason

Enable HTTP Keep-Alives tries to keep connections open to allow clients to download multiple resources without the overhead of setting up a new connection for each one. The timeout is how long it waits.

Even with a setting of unlimited connections in IIS there is still a limit to the number of connections the machine can handle. By repeatedly setting up new ones in your hammering test you have reached that limit and blocked a new on being made by telnet.

By disabling http keep alive or reducing the timeout, you have increased the turnover of connections but at the expense of increasing the overhead to realworld browsers who do not behave in the same way as your test client. In trying to gain performance you may have actually reduced it.

Like most things, finding the best setting is a balancing act which will depend on your actual usage.

Here is a Microsoft explanation on how to fully remove IIS 5.1 from Windows XP and then reinstall it.

To uninstall:

1. Locate the Iis5.log file. Rename it to IIS5_old.log.
2. Click Start, click Run, type cmd, and then click OK.
3. At the command prompt, type net stop iisadmin /y.
4. Stop all services that depend on IIS services. To determine what services depend on IIS services, follow these steps:
5. In Task Manager, verify that Inetinfo.exe is not running. Also confirm that no processes that depend on IIS are running.
6. Click Start, click Run, type Appwiz.cpl, and then click OK.
7. In Control Panel, double-click Add/Remove Programs.
8. In the Add/Remove Programs window, click Add/Remove Windows Components.
9. In the Components box of the Windows Components Wizard, double-click Application Server.
10. Click to clear the Internet Information Services (IIS) check box, and then click OK.
11. In the Windows Components Wizard, click Next.
12. When the Windows Components Wizard completes the installation, click Finish.
13. Restart the computer.
14. Click Start, click Run, type Lusrmgr.msc, and then click OK.
15. In the Local Users and Groups windows, verify that the IWAM_computername and IUSR_computername account have been deleted.
16. Verify that the Inetsrv folder has been deleted. By default, the Inetsrv folder is located in the %Windir%\System32 folder.

I have omitted a few of the notes included with the instruction.

To reinstall:

1. Click Start, click Run, type Appwiz.cpl, and then click OK.
2. In the Add/Remove Programs window, click Add/Remove Windows Components.
3. In the Components box of the Windows Components Wizard, click to select the Internet 4. Information Services (IIS) check box.
4. In the Windows Components Wizard, click Next.
5. When the Windows Components Wizard completes the installation, click Finish.