D-Link DIR-803 User Manual page 83

Section 3 - Configuration
IPSec (VPN): Allows multiple VPN (Virtual Private Network) clients to connect to their corporate network using IPSec (Internet Protocol Security).
Some VPN clients support traversal of IPSec through NAT (Network Address Translation). This ALG (Application Level Gateway) may
interfere with the operation of such VPN clients. If you are having trouble connecting with your corporate network, try turning this
ALG off. Check with the system administrator of your corporate network whether your VPN client supports NAT traversal.
Allows application that uses RTSP (Real Time Streaming Protocol) to receive streaming media from the Internet. QuickTime and
RTSP:
Real Player are some of the common applications using this protocol.
SIP:
Allows devices and applications using VoIP (Voice over IP) to communicate across NAT. Some VoIP applications and devices have
the ability to discover NAT devices and work around them. This function may interfere with the operation of such devices. If you
are having trouble making VoIP calls, try turning this option off.
Click Save Settings.
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