The Firewall Screen - ZyXEL Communications P-870HN-51B - V1.0 Manual

Chapter 10 Firewall
Some of the most common IP ports are:
Table 46 Common IP Ports
21
23
25
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 ZyXEL Device's default
rules.

10.3 The Firewall Screen

Click Security > Firewall > Incoming to display the following screen. This
screen displays a list of the configured incoming filtering rules.
Figure 77 Firewall > Incoming
152
FTP 53
Telnet 80
SMTP 110
DNS
HTTP
POP3
P-870HN-51b User's Guide