Contemporary Controls EIGR Series Application Manual page 11

Application #7 – Router Access from a WAN-side Device
In some situations, you may want a WAN-side device to
access and possibly configure the router. This is enabled via
the Remote Router Access control (shown below) found
under the Administration tab.
Enhance Security with a Whitelist
Specify which WAN-side devices
Application #8 – Port Address Translation (PAT)
PAT (also known as a firewall) allows a many-to-one mapping
of private IP addresses to one public address. Not only does
this provide enhanced security for the devices on the LAN
side, it also allows multiple LAN-side devices to communicate
to devices on the WAN side using only one WAN IP address.
When the WAN network is connected to the Internet, this
allows the LAN devices to communicate on the Internet via
one public IP address.
Internal IP Address
192.168.92.101/24
192.168.92.102/24
192.168.92.101
192.168.92.102
can configure the router.
LAN IP Port External IP Address
5001 1.2.3.4
5002 1.2.3.4
Application Guide – EIGR Series
Caution: Enabling this control grants access to any
device on the public or WAN-side. To restrict access to just
certain WAN devices, you must construct a whitelist such
as the example below which specifies an outside (public or
WAN-side) device that has the IP address of 4.3.2.1.
Most ISPs will limit the number of public IP addresses
provided to their customers. PAT is done by the use of port
assignments — thus, granting private IP addresses access to
the Internet. In this example, the ISP provided the router the
public address of 1.2.3.4. Both LAN-side PCs have
automatically been assigned local IP ports and granted access
to the Internet — and no configuration was needed.
STATUS PWR
RESET
1.2.3.4
H
WAN
L
1
2
LAN
3
4
192.168.92.1
11 AG-EIGR0000-AA0