D-Link DIR-890L User Manual page 67

Section 3 - Configuration
PPTP: Click to enable PPTP, which will allow multiple machines on the
LAN to connect to their corporate network using the PPTP protocol.
IPSec (VPN): Enable to allow multiple VPN clients to connect to their corporate
network using IPSec. Some VPN clients support traversal of IPSec
through NAT. This Application Level Gateway (ALG) 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 to
find out whether your VPN client supports NAT traversal.
RTSP: Enable to allow applications that use Real Time Streaming Protocol
(RTSP) to receive streaming media from the Internet.
SIP:
Enable to allow 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
Application Level Gateway (ALG) may interfere with the operation of
such devices. If you are having trouble making VoIP calls, try turning
this ALG off.
Click Save when you are done.
D-Link DIR-890L User Manual 62