1. Home
    2. /
  2. Manuals
    3. /
  3. Zyxel
    4. /
  4. NBG5615
    5. /
  5. 21
Page 101 / 252 Scroll up to view Page 96 - 100
Chapter 14 NAT
NBG5715 User’s Guide
101
all incoming inquiries, thus preventing intruders from probing your network. For more information
on IP address translation, refer to
RFC 1631
,
The IP Network Address Translator (NAT)
.
How NAT Works
Each packet has two addresses – a source address and a destination address. For outgoing packets,
the ILA (Inside Local Address) is the source address on the LAN, and the IGA (Inside Global
Address) is the source address on the WAN. For incoming packets, the ILA is the destination
address on the LAN, and the IGA is the destination address on the WAN. NAT maps private (local)
IP addresses to globally unique ones required for communication with hosts on other networks. It
replaces the original IP source address in each packet and then forwards it to the Internet. The
NBG5715 keeps track of the original addresses and port numbers so incoming reply packets can
have their original values restored. The following figure illustrates this.
Figure 62
How NAT Works
14.2
The NAT General Screen
Use this screen to enable NAT and set a default server. Click
Network > NAT
to open the
General
screen.
Figure 63
Network > NAT > General
Page 102 / 252
Chapter 14 NAT
NBG5715 User’s Guide
102
The following table describes the labels in this screen.
14.3
The Port Forwarding Screen
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 NBG5715’s port forwarding settings, click
Network > NAT
>
Port
Forwarding
. The screen appears as shown.
Note: If you do not assign a
Default Server
, the NBG5715 discards all packets received
for ports that are not specified in this screen or remote management.
Refer to
Appendix E on page 237
for port numbers commonly used for particular services.
Table 45
Network > NAT > General
LABEL
DESCRIPTION
Network Address
Translation (NAT)
Network Address Translation (NAT) allows the translation of an Internet protocol
address used within one network (for example a private IP address used in a
local network) to a different IP address known within another network (for
example a public IP address used on the Internet).
Select
Enable
to activate NAT. Select
Disable
to turn it off.
Max NAT/Firewall
Session Per User
Specify the highest number of NAT sessions that the NBG5715 will permit a host
to have at one time.
Apply
Click
Apply
to save your changes back to the NBG5715.
Cancel
Click
Cancel
to begin configuring this screen afresh.
Page 103 / 252
Chapter 14 NAT
NBG5715 User’s Guide
103
Figure 64
Network > NAT > Port Forwarding
The following table describes the labels in this screen.
Table 46
Network > NAT > Port Forwarding
LABEL
DESCRIPTION
Default Server Setup
Default Server
In addition to the servers for specified services, NAT supports a default server. A
default server receives packets from ports that are not specified in the
Port
Forwarding
screen. You can decide whether you want to use the default server
or specify a server manually.
Select this to use the default server.
Change to Server
Select this and manually enter the server’s IP address.
Port Forwarding
Service Name
Select a pre-defined service from the drop-down list box. The pre-defined
service port number(s) and protocol will be displayed in the
Port Forwarding
Summary
section.
Otherwise, select
User define
to manually enter the port number(s) and select
the IP protocol.
Service Protocol
Select the transport layer protocol supported by this virtual server. Choices are
TCP
,
UDP
, or
TCP&UDP
.
If you have chosen a pre-defined service in the
Service Name
field, the protocol
will be configured automatically.
Server IP Address
Enter the inside IP address of the virtual server here and click
Add
to add it in
the
Port Forwarding Summary
section.
Port Forwarding Summary
#
This is the number of an individual port forwarding server entry.
Status
This icon is turned on when the rule is enabled.
Name
This field displays a name to identify this rule.
Protocol
This is the transport layer protocol used for the service.
Port
This field displays the port number(s).
Server IP Address
This field displays the inside IP address of the server.
Modify
Click the
Edit
icon to open the edit screen where you can modify an existing
rule.
Click the
Remove
icon to delete a rule.
Page 104 / 252
Chapter 14 NAT
NBG5715 User’s Guide
104
14.3.1
Port Forwarding Edit Screen
This screen lets you create or edit a port forwarding rule. Click the
Add Port Forward
button or a
rule’s
Edit
icon in the
Port Forwarding
screen to open the following screen.
Figure 65
NAT > Port Forwarding Edit
The following table describes the labels in this screen.
Apply
Click
Apply
to save your changes back to the NBG5715.
Cancel
Click
Cancel
to begin configuring this screen afresh.
Table 46
Network > NAT > Port Forwarding (continued)
LABEL
DESCRIPTION
Table 47
NAT > Port Forwarding Edit
LABEL
DESCRIPTION
Port Forwarding
Select
Enable
to turn on this rule and the requested service can be forwarded to
the host with a specified internal IP address.
Select
Disable
to disallow forwarding of these ports to an inside server without
having to delete the entry.
Service Name
Type a name (of up to 31 printable characters) to identify this rule in the first field
next to
Service Name
. Otherwise, select a predefined service in the second field
next to
Service Name
. The predefined service name and port number(s) will
display in the
Service Name
and
Port
fields.
Protocol
Select the transport layer protocol supported by this virtual server. Choices are
TCP
,
UDP
, or
TCP&UDP
.
If you have chosen a pre-defined service in the
Service Name
field, the protocol
will be configured automatically.
Port
Type a port number(s) to define the service to be forwarded to the specified
server.
To specify a range of ports, enter a hyphen (-) between the first port and the last
port, such as 10-.
Server IP
Address
Type the IP address of the server on your LAN that receives packets from the
port(s) specified in the
Port
field.
Back
Click
Back
to return to the previous screen.
Apply
Click
Apply
to save your changes back to the NBG5715.
Cancel
Click
Cancel
to begin configuring this screen afresh.
Page 105 / 252
Chapter 14 NAT
NBG5715 User’s Guide
105
14.4
The NAT Advance Screen
To change your NBG5715’s trigger port settings, click
Network > NAT > NAT Advance
. The
screen appears as shown.
Note: Only one LAN computer can use a trigger port (range) at a time.
Figure 66
Network > NAT > NAT Advance
The following table describes the labels in this screen.
Table 48
Network > NAT > NAT Advance
LABEL
DESCRIPTION
Port Triggering Rules
#
This is the rule index number (read-only).
Name
Type a unique name (up to 15 characters) for identification purposes. All
characters are permitted - including spaces.
Incoming
Incoming is a port (or a range of ports) that a server on the WAN uses when it
sends out a particular service. The NBG5715 forwards the traffic with this port
(or range of ports) to the client computer on the LAN that requested the service.
Port
Type a port number or the starting port number in a range of port numbers.
End Port
Type a port number or the ending port number in a range of port numbers.
Trigger
The trigger port is a port (or a range of ports) that causes (or triggers) the
NBG5715 to record the IP address of the LAN computer that sent the traffic to a
server on the WAN.
Port
Type a port number or the starting port number in a range of port numbers.
End Port
Type a port number or the ending port number in a range of port numbers.
Apply
Click
Apply
to save your changes back to the NBG5715.
Reset
Click
Reset
to begin configuring this screen afresh.

Rate

4 / 5 based on 1 vote.

Popular Zyxel Models

Famous Router IPs
Famous Router Companies
Bookmark Our Site

Press Ctrl + D to add this site to your favorites!

Share
Top