How to disable the application pool idle time-out in IIS7?

Question

Yes, setting the idle timeout value to zero will disable idle timeouts.

Oddly this isn’t documented in the MS docs but my evidence for this arises from:

IIS Settings Schema

If you have a look at the IIS settings schema in:

C:\Windows\System32\inetsrv\config\schema\IIS_schema.xml

The schema definition for idleTimeout under

<sectionSchema name="system.applicationHost/applicationPools">

it looks like:
```
<attribute name="idleTimeout" 
       type="timeSpan" 
       defaultValue="00:20:00" 
       validationType="timeSpanRange" 
       validationParameter="0,2592000,60"/>
```
If you look at the validationParameter attribute we see a range of 0 to 2592000 seconds (the ,60 specifies the granularity of the setting, in this case the value must be divisable by 60 [one minute]).

If you see a starting permissible value of 0 then that usually indicates the setting can be disabled.
IIS7 Application Pool Idle Time-out Settings

Brad Kingsley is the founder and CEO of OrcsWeb who are a fairly well known, respected and trusted Microsoft hoster and Gold Partner.
Then there’s also the empirical evidence of the fact that it “just works”.