User manual

Wireless Adapter RNX-N4 User Manual

gives a compromise position, which avoids problems when communicating with certain

other types of NAT router (symmetric NATs in particular) but leaves inbound filters and

scheduled access working as expected.

• Enable Port Preservation: Place a check in this box to enable Port Preservation. NAT

Port preservation (on by default) tries to ensure that, when a LAN host makes an Internet

connection, the same LAN port is also used as the Internet visible port. This ensures

best compatibility for internet communications. Under some circumstances it may be

desirable to turn off this feature.

• Enable anti-spoof checking: Place a check in this box to enable anti-spoof checking.

Enabling this option can provide protection from certain kinds of "spoofing" attacks.

However, enble this option with care. With some modems, the WAN connection may be

lost when this option is enabled. In that case, it may be necessary to change the LAN

subnet to something other than 192.168.0.x (192.168.2.x, for example), to re-establish

the WAN connection.

• Enable DMZ Host: Place check in this box to enable DMZ host. DMZ host is a

demilitarized zone used to provide Internet services without sacrificing unauthorized

access to its local private network. Typically, the DMZ host contains devices

accessible to Internet traffic, such as web, FTP, email and DNS servers.

• DMZ IP Address: Specify the IP address of the DMZ host.

• Non-UDP/TCP/ICMP LAN Sessions: Place a check in this box to enable this feature.

When a LAN application that uses a protocol other than UDP, TCP, or ICMP initiates a

session to the Internet, the router's NAT can track such a session, even though it does

not recognize the protocol. This feature is useful because it enables certain

applications (most importantly a single VPN connection to a remote host) without the

need for an ALG.

• Note: This feature does not apply to the DMZ host (if one is enabled). The DMZ host

always handles these kinds of sessions.

• Enabling this option (the default setting) enables single VPN connections to a remote

host. (But, for multiple VPN connections, the appropriate VPN ALG must be used.)

Disabling this option, however, only disables VPN if the appropriate VPN ALG is also

disabled.