ZyXEL P-662HW-61 User Guide - Page 171

Connection Direction

Page 171 highlights

Chapter 11 Firewall Configuration 4 Does a rule that allows Internet users access to resources on the LAN create a security vulnerability? For example, if FTP ports (TCP 20, 21) are allowed from the Internet to the LAN, Internet users may be able to connect to computers with running FTP servers. 5 Does this rule conflict with any existing rules? 6 Once these questions have been answered, adding rules is simply a matter of plugging the information into the correct fields in the web configurator screens. 11.3.2 Key Fields For Configuring Rules 11.3.2.1 Action Should the action be to Drop, Reject or Permit? " "Drop" means the firewall silently discards the packet. "Reject" means the firewall discards packets and sends an ICMP destination-unreachable message to the sender. 11.3.2.2 Service Select the service from the Service scrolling list box. If the service is not listed, it is necessary to first define it. See Section 11.8 on page 183 for more information on predefined services. 11.3.2.3 Source Address What is the connection's source address; is it on the LAN or WAN? Is it a single IP, a range of IPs or a subnet? 11.3.2.4 Destination Address What is the connection's destination address; is it on the LAN or WAN? Is it a single IP, a range of IPs or a subnet? 11.4 Connection Direction This section describes examples for firewall rules for connections going from LAN to WAN and from WAN to LAN. Rules for the DMZ work in a similar fashion. LAN to LAN/ Router, WAN to WAN/ Router and DMZ to DMZ/Router rules applies to packets coming in on the associated interface (LAN, WAN, or DMZ respectively). LAN to LAN/ Router means policies for LAN-to-ZyXEL Device (the policies for managing the ZyXEL Device through the LAN interface) and policies for LAN-to-LAN (the policies that control routing between two subnets on the LAN). Similarly, WAN to WAN/ Router and DMZ to DMZ/ Router polices apply in the same way to the WAN and DMZ ports. P-662H/HW-D Series User's Guide 171

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Chapter 11 Firewall Configuration
P-662H/HW-D Series User’s Guide
171
4
Does a rule that allows Internet users access to resources on the LAN create a security
vulnerability? For example, if FTP ports (TCP 20, 21) are allowed from the Internet to
the LAN, Internet users may be able to connect to computers with running FTP servers.
5
Does this rule conflict with any existing rules?
6
Once these questions have been answered, adding rules is simply a matter of plugging
the information into the correct fields in the web configurator screens.
11.3.2
Key Fields For Configuring Rules
11.3.2.1
Action
Should the action be to
Drop
,
Reject
or
Permit
?
“Drop” means the firewall silently discards the packet. “Reject” means the
firewall discards packets and sends an ICMP destination-unreachable
message to the sender.
11.3.2.2
Service
Select the service from the
Service
scrolling list box. If the service is not listed, it is necessary
to first define it. See
Section 11.8 on page 183
for more information on predefined services.
11.3.2.3
Source Address
What is the connection’s source address; is it on the LAN or WAN? Is it a single IP, a range of
IPs or a subnet?
11.3.2.4
Destination Address
What is the connection’s destination address; is it on the LAN or WAN? Is it a single IP, a
range of IPs or a subnet?
11.4
Connection Direction
This section describes examples for firewall rules for connections going from LAN to WAN
and from WAN to LAN. Rules for the DMZ work in a similar fashion.
LAN to LAN/ Router, WAN to WAN/ Router and DMZ to DMZ/Router rules applies to
packets coming in on the associated interface (LAN, WAN, or DMZ respectively). LAN to
LAN/ Router means policies for LAN-to-ZyXEL Device (the policies for managing the
ZyXEL Device through the LAN interface) and policies for LAN-to-LAN (the policies that
control routing between two subnets on the LAN). Similarly, WAN to WAN/ Router and DMZ
to DMZ/ Router polices apply in the same way to the WAN and DMZ ports.