Net.Tcp WCF service requires 'Integrated' managed pipeline mode, not 'classic' mode

We built and successfully tested a Net.Tcp WCF service. But when deploying it to an off-site server for further testing, we discovered the IIS worker process was crashing.

In the event log, we got plenty of these:


Source: ASP.NET 4.0.30319.0
EventID: 1088
Description: 0x8000ffff Catastrophic failure


and some of these:


Faulting application name: w3wp.exe, version: 7.5.7600.16385, time stamp: 0x4a5bcd2b
Faulting module name: unknown, version: 0.0.0.0, time stamp: 0x00000000
Exception code: 0xc0000005
Fault offset: 0x00000000
Faulting process id: 0xfe8
Faulting application start time: 0x01cb429f60c2c986
Faulting application path: C:\Windows\SysWOW64\inetsrv\w3wp.exe
Faulting module path: unknown
Report Id: f85bf6d3-ae92-11df-a403-00219b00a9ca


We had to issue an 'iisreset' command from command line to bring it back.

It turns out, the offsite servers were running our application using a 'Classic' mode app-pool. But during development, we used 'Integrated' managed pipeline mode.

Changing the offsite servers to 'Integtated' seemed to fix the problem.