Threshold - ZyXEL Communications Vantage CNM 2.3 User Manual

Centralized network management

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Table of Contents

Chapter 6 Device Security Settings

Ping requests and whether or not the device is to respond to probing for unused

Figure 52 Device Operation > Device Configuration > Security > Firewall > Anti-

The following table describes the labels in this screen.

Table 45 Device Operation > Device Configuration > Security > Firewall > Anti-

Do not respond

to requests for

unauthorized

6.1.5 Threshold

Click Device Operation in the menu bar and then click Device Configuration >

Security > Firewall > Threshold in the navigation panel to bring up the next

Select the interfaces on which you want the device to reply to incoming

Ping requests.

Select this option to prevent hackers from finding the device by probing

for unused ports. If you select this option, the device will not respond to

port request(s) for unused ports, thus leaving the unused ports and the

device unseen. If this option is not selected, the device will reply with

an ICMP port unreachable packet for a port probe on its unused UDP

ports and a TCP reset packet for a port probe on its unused TCP ports.

Note that the probing packets must first traverse the device's firewall

rule checks before reaching this anti-probing mechanism. Therefore if a

firewall rule stops a probing packet, the device reacts based on the

firewall rule to either send a TCP reset packet for a blocked TCP packet

(or an ICMP port-unreachable packet for a blocked UDP packets) or just

drop the packets without sending a response packet.

Click this to save your changes back to the device.

Click this to begin configuring this screen afresh.

Vantage CNM User's Guide