ZyXEL Communications NVG2053, User Manual

Page: 162 / 200

Chapter 16 Firewall
NVG2053 User’s Guide
162
Some of the most common IP ports are:
Default Filtering Policies
Filtering rules are grouped based on the direction of travel of packets to which
they apply.
The default rule for incoming traffic blocks all incoming connections from the WAN
to the LAN. If you wish to allow certain WAN users to have access to your LAN,
you will need to create custom rules to allow it.
Note: If you configure filtering rules without a good understanding of how they work,
you might inadvertently introduce security risks to the firewall and to the
protected network. Make sure you test your rules after you configure them.
These custom rules work by comparing the Source IP address, Destination IP
address and IP protocol type of network traffic to rules set by the administrator.
Your customized rules take precedence and override the NVG2053’s default rules.
16.3 The General Firewall Screen
Use this screen to enable or disable the NVG2053’s firewall. Click Configuration
> Security > Firewall to open the General screen.
Figure 68 Security > Firewall > General
Table 51 Common IP Ports
21 FTP 53 DNS
23 Telnet 80 HTTP
25 SMTP 110 POP3