Perle Systems IOLINK-520 - Manual (Page 68)

Applications
2.48 — IOLINK-520 & IOLINK-PRO Installation & Applications Guide
2.4.3.3 - Configure Firewall
The IOLINK-520 & IOLINK-PRO provide Firewall security for restricting access between
any two networks connected through the router. Firewalls are set-up on a per connection
basis for the LAN and remote sites. The direction of filtering is from the perspective of the
IOLINK router; incoming traffic is from the network in question to the IOLINK router,
outgoing is from the IOLINK router to the network. The direction of filtering may be set to
incoming, outgoing, both or none. Once the direction of filtering for a connection has been
set, holes may be created in the firewall to allow specified traffic through. Normally, the
LAN firewall is used for restricting intranet traffic (connections within the corporate network)
and remote site firewalls are used to limit access from less trusted sources, such as the Internet
or dial-up ISDN links.
The following diagram shows a corporate head office network, which is connected, to the
Internet with an IOLINK router. There is also a branch office at a remote site connected
with a leased link. The administrator at the corporate head office wishes to set-up an IP
firewall to allow everyone on the Internet to have access to the corporate FTP and Web
servers and nothing else. The administrator also wishes to allow all of the TCP traffic from
the branch office network to have access to the head office. Anyone in the corporation may
have unrestricted access to the Internet.
Figure 2 -13 Sample Firewall Application
The following steps must be performed on the IOLINK-520 & IOLINK-PRO to set-up
the firewall support as desired.
Internet
Router with
firewall enabled.
Corporate Head
Office Network
195.100.1.0
Branch Office
Network
195.100.2.0
Any other network
any IP address
Main FTP server: 195.100.1.12
Main Web server: 195.100.1.20