The Firewall Threshold Screen; Figure 89 Security > Firewall > Rules: Edit: Edit Customized Services: Config; Table 56 Security > Firewall > Rules: Edit: Edit Customized Services: Config - ZyXEL Communications P-660HN-F1 User Manual

Figure 89 Security > Firewall > Rules: Edit: Edit Customized Services: Config
The following table describes the labels in this screen.
Table 56 Security > Firewall > Rules: Edit: Edit Customized Services: Config
LABEL
Config
Service Name
Service Type
Port Configuration
Type
Port Number
Back
Apply
Cancel
Delete

9.4 The Firewall Threshold Screen

For DoS attacks, the ZyXEL Device uses thresholds to determine when to start dropping
sessions that do not become fully established (half-open sessions). These thresholds apply
globally to all sessions.
For TCP, half-open means that the session has not reached the established state-the TCP three-
way handshake has not yet been completed. Under normal circumstances, the application that
initiates a session sends a SYN (synchronize) packet to the receiving server. The receiver
sends back an ACK (acknowledgment) packet and its own SYN, and then the initiator
responds with an ACK (acknowledgment). After this handshake, a connection is established.
P-660HN-F1 User's Guide
DESCRIPTION
Type a unique name for your custom port.
Choose the IP port (TCP, UDP or TCP/UDP) that defines your customized port from
the drop down list box.
Click Single to specify one port only or Range to specify a span of ports that define
your customized service.
Type a single port number or the range of port numbers that define your customized
service.
Click this to return to the previous screen without saving.
Click this to save your changes.
Click this to restore your previously saved settings.
Click this to delete the current rule.
Chapter 9 Firewalls
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