How to determine if internet is available even if app is blocked

[Linda]

I'm writing some support functionality into a company product.

Sometimes a firewall product blocks us from talking to the internet because
the user didn't pay attention when the firewall software asked them if it
was ok for us to access.

Sometimes we are just blocked by random firewall manufacturers for unknown
reasons.

I'm looking for a way to see if the computer itself has internet
connectivity even if we don't.
This will allow me to give them a better message about how to proceed.


Any ideas?


-Linda

 

[Kellie Fitton]

Hi,

You can use the following APIs to verify internet connection:

InetIsOffline()

IsNetworkAlive()

IsDestinationReachable()

http://msdn.microsoft.com/library/d...m/shell/reference/functions/inetisoffline.asp

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/syncmgr/syncmgr/isnetworkalive.asp

http://msdn.microsoft.com/library/d...wininet/wininet/internetgetconnectedstate.asp

Hope these information helps,

Kellie.

 

[Eugene Gershnik]

I'm looking for a way to see if the computer itself has internet
connectivity even if we don't.

http://www.gershnik.com/faq/manage.asp#internet

 

[Scherbina Vladimir]

Hello, Linda...

Another solution is to change settings of firewall (if it's XP SP2 for
example) - HNetCfg.FwMgr COM object allows you to manipulate XP Firewall
settings. You may add your application to AuthorizedApplications of XP SP2
firewall in order to prevent blocking your program.

 

[Linda]

Hello, Linda...

Another solution is to change settings of firewall (if it's XP SP2 for
example) - HNetCfg.FwMgr COM object allows you to manipulate XP
Firewall settings. You may add your application to
AuthorizedApplications of XP SP2 firewall in order to prevent blocking
your program.

Thanks all for your suggestions.

I've got the functions Kellie mentioned to work (IsNetworkAlive,
InternetGetConnectedState,IsDestinationReachable), so we're testing those
on some of the incompatible firewalls now.

Thanks for the link Eugene. I'll try InternetCheckConnection() and
RasEnumConnections() if we can't get the others to do what we want.

Scherbina, we're actually adding ourselves to the windows firewall, it's
these 3rd party products who have different rules about outright blocking
or asking users with popup's, etc... that we're having trouble with.


-Linda