How do firewalls block you?

[DeepT]

I have a network app that is fairly new (about a year old) and we are running into several problems with third party firewalls and AV software not recognizing our product and blocking us.

So, how does an appliction, such as McAffe block our app from using sockets?

Is there a way to tell if we have been blocked because of this kind of issue so that we may inform the user so that he or she may fix the problem?

Is there a way we can unblock outselves?

[Siddhartha]

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Regards,
Siddhartha

[Ejaz]

Firewall

[cipher1024]

hi,
I faced a similar problem some time back while creating a network application.Most commercial firewall applications maintain something like a trusted applications list . So it is the job of the user to add ur application to the trusted applications list. The firewall must be configured by the user and there's not much u can do from ur application to fool the firewall unless ur creating a virus or trojan. This is the solution i came up with (not sure if it's the best) so if u know a better solution please let me know too.

[MikeAThon]

I tend to agree with the answer given by cipher1024. At least in the general case, the best you can do is to display a dialog to the user, telling them that they must add your program to the list of trusted programs in their firewall.

However, in the special case where your user is using Windows Firewall, there is actually an API that would allow you to programmatically add your program to the trusted list, so long as the user has administrator privileges. See "About Windows Firewall API", at http://msdn.microsoft.com/library/en...s_firewall.asp

I have not used it (since it does not solve the general case), but the MSDN site has code samples that look promising.

Mike

[DeepT]

Well neither of these really answers my question. Assuming there is an unknown firewall appliction blocking my app, how am I to tell that is the case?

And once again, by what mechanics on windows is this done? Is it all some big hack or is there a proper API to all this? That API seems specifically for the "Windows" firewall opposed to any firewall.

I guess I am looking for a very technical "How-To" on firewalls which would explain how I would make my own firewall.