Xử lý lỗi IIS 6

To work around this issue, add the EnableAggressiveMemoryUsage registry entry to the following registry subkey:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\HTTP\Parameters

Then, set the EnableAggressiveMemoryUsage registry entry to 1. 

To do this, follow these steps:

1. Click Start, click Run, type regedit in the Open box, and then click OK.
2. Click the following registry subkey:
   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\HTTP\Parameters
3. On the Edit menu, point to New, and then click DWORD Value.
4. Type EnableAggressiveMemoryUsage, and then press ENTER.
5. On the Edit menu, click Modify.
6. In the Value data box, type 1, and then click OK.
7. On the File menu, click Exit to exit Registry Editor.
8. Restart the HTTP service. To do this, follow these steps:
1. Click Start, click Run, type cmd in the Open box, and then click OK.
2. At the command prompt, type net stop http /y, and then press ENTER.
3. At the command prompt, type iisreset /restart, and then press ENTER.

Relate Article:

http://blogs.msdn.com/b/amol/archive/2012/02/29/troubleshooting-quot-connections-refused-quot-errors-seen-httperr-logs.aspx

http://support.microsoft.com/kb/934878

http://zachbonham.blogspot.com/2007/11/httperr-connectionsrefused.html

http://blogs.msdn.com/b/david.wang/archive/2005/09/21/howto-diagnose-iis6-failing-to-accept-connections-due-to-connections-refused.aspx

http://support.microsoft.com/?id=177415