Port Forwarding - ZyXEL Communications LTE2566-M634 User Manual

The following table summarizes how these NAT types handle outgoing and incoming packets.
Table 28 NAT Types
Incoming
Packets
Outgoing
Packets

10.2 Port Forwarding

Use this screen to forward incoming service requests to the server(s) on your local network and set a
default server. You may enter a single port number or a range of port numbers to be forwarded, and the
local IP address of the desired server. The port number identifies a service; for example, web service is on
port 80 and FTP on port 21. In some cases, such as for unknown services or where one server can support
more than one service (for example both FTP and web service), it might be better to specify a range of
port numbers.
In addition to the servers for specified services, NAT supports a default server. A service request that does
not have a server explicitly designated for it is forwarded to the default server. If the default is not
defined, the service request is simply discarded.
Note: Many residential broadband ISP accounts do not allow you to run any server processes
(such as a Web or FTP server) from your location. Your ISP may periodically check for
servers and may suspend your account if it discovers any active services at your
location. If you are unsure, refer to your ISP.
Port forwarding allows you to define the local servers to which the incoming services will be forwarded.
To change your LTE2566-M634's port forwarding settings, click Configuration > Network > NAT > Port
Forwarding. The screen appears as shown.
Chapter 10 NAT
ADDRESS
FULL CONE
RESTRICTED
Any external host Only external hosts
can send packets to with an IP address to
the mapped which the internal
external IP address host has already
and port. sent a packet can
send packets to the
mapped external IP
address and port.
The NAT router maps the internal IP address and port of all outgoing
packets to a single IP address and port on the external network.
LTE2566-M634 User's Guide
PORT RESTRICTED
Only external hosts
with an IP address
and port to which the
internal host has
already sent a packet
can send packets to
the mapped external
IP address and port.
76
SYMMETRIC
A host on the external
network can only send
packets to the specific
mapped external IP
address and port that the
NAT router used in sending
a packet to the external
host's IP address and port.
The NAT router maps the
internal IP address and
port of each outgoing
packet to a different
external IP address and
port for each different
destination IP address and
port.