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# SystemConfiguration Functions

## Topics

### Functions

[`CFArrayRefCNCopySupportedInterfaces();`](/documentation/SystemConfiguration/CNCopySupportedInterfaces)

Returns the names of all network interfaces Captive Network Support is monitoring.

[`Boolean CNMarkPortalOffline(CFStringRef interfaceName);`](/documentation/SystemConfiguration/CNMarkPortalOffline)

Informs Captive Network Support that the device is not authenticated on a captive network.

[`Boolean CNMarkPortalOnline(CFStringRef interfaceName);`](/documentation/SystemConfiguration/CNMarkPortalOnline)

Informs Captive Network Support that the application has successfully authenticated the device to a captive network. Captive Network Support notifies the rest of the system that WiFi is a viable interface.

[`Boolean CNSetSupportedSSIDs(CFArrayRef ssidArray);`](/documentation/SystemConfiguration/CNSetSupportedSSIDs)

Specifies an updated list of captive network SSIDs that the application performs authentication on.

[`CFDateRefDHCPInfoGetLeaseExpirationTime(CFDictionaryRef info);`](/documentation/SystemConfiguration/DHCPInfoGetLeaseExpirationTime)

Returns the lease expiration time data.

### Deprecated

[`CFDictionaryRefCNCopyCurrentNetworkInfo(CFStringRef interfaceName);`](/documentation/SystemConfiguration/CNCopyCurrentNetworkInfo)

Returns the current network information for a given network interface.


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