Mysterious Problem in WCF and IIS?

Question

Hi
I wrote WCF duplex service. This service work Fine in Visual studio but when I publish this service and put it on IIS , Service don\'t answer to an

Answer 1

First of all Duplex is bad (really bad) but I am not gonna blabber about that since you have made the decision to use it.

The main problem I can see is security. I am sure windows eventlog will tell you stories on this - just check the errors on security log. By default, IIS application pools are not allowed to communicate with other machines. You did not mention that you have specifically done anything about it so I assume it is all default. Just change the Identity of the App Pool to an admin user (al thought not recommended for production) and I think you will see your problem going away - I just guess.

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OFF-TOPIC: WHY DUPLEX IS BAD

• With server trying to establish a connection back to the client, it heavily reduces the scalability of the service. In fact if the client has a bad connection or ... server's connection could be hanging there until it times out during which time, all the resources dedicated to that call will be locked hence wasted.
• Spec of the client machine and its connection can affect the performance of the service.
• For server it is usually made sure that it is accessible. If client is behind a firewall or NAT, they can not contact the server. [THIS IN FACT COULD BE YOUR PROBLEM].
• So if you open up the client for the server, it means the client could be also exposed to the whole world. Security considerations for the servers are usually good but the clients they are ignored so whole lots of things now need to be considered.
• And there are more... but that should be enough.

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