When configuring PHP in IIS, the Service Unavailable problem occurs.

Recently I used an asp cms version. When I was about to put it on the server, I found that Apache2.09 was used on the server. Asp is not supported by default. The solution to the spread on the Internet is to use the IASP program to expand Apache's support for Asp. However, another problem is that it must have a JAVA environment, it seems that Apache2 and later versions are not very compatible. Because there are two PHP sites on the server, only Apache is available and IIS is used. Previously, PHP programs were deployed on the server, all of which only needed simple configuration and online processes. However, a problem was found during the configuration process, which is recorded here, for future use. It is not an installation version. The general PHP step is to set the php under the php Directory. ini, then copy it to the C: \ Windows directory, and then copy php5ts. copy the dll to the C: \ WINDOWS \ system32 directory. Then, "Web Service extension" under IIS → Add a new Web Service extension. Add: php5isapi under the php Directory. dll, name: PHP sets the extension status to allow: under IIS, choose "website"> "default website"> "properties"> "main directory"> "configuration ing"> Add an executable file: php5isapi under the php Directory. dll extension :. PHP. So far, the configuration has been successful. At least on the server I contacted, the PHP site can run. However, there is another step in the online process, which wastes a lot of time. Press IIS → "properties" → "ISAPI filter" → add Filter Name: PHP Executable File: php5isapi. dll in the php Directory. Add a php ing file. After I add the last one, Service Unavailable will appear as long as I access the site, whether it is Asp or PHP. Download PHP and reinstall it. Later, an IIS Filter error was found in the Windows Log. Open the IIS Filter and find that the added PHP icon is red and the status is not loaded. So I deleted it and accessed the site again.