Related information:
View all Server Variables
ServerVariables collection retrieves the intended meaning of environment variables
Today I suddenly remembered that the values of HTTP_HOST and SERVER_NAME are always the same every time I request it. Why do I use two names? What is the difference between them?
There is no definite statement on the Internet, and I found an explanation on Microsoft:
SERVER_NAME is equal to HTTP_HOST under Windows 2000
Under Windows 2003
>> The following number * is Request.ServerVariables("APPL_MD_PATH") requested /LM/W3SVC/*/ROOT
When running "CScript adsutil.vbs Set w3svc/*/UseHostName true" under CMD
SERVER_NAME is the computer name of Windows
When running "CScript adsutil.vbs Set w3svc/*/UseHostName flag" under CMD
SERVER_NAME equals HTTP_HOST
Reprinted from: http://jorkin.reallydo.com/article.asp?id=161