ZyXEL Vantage CNM User Guide - Page 132

Chapter 6 Device Security Settings Ping requests and whether or not the device is to respond to probing for unused ports. Figure 52 Device Operation > Device Configuration > Security > Firewall > AntiProbing The following table describes the labels in this screen. Table 45 Device Operation > Device Configuration > Security > Firewall > AntiProbing LABEL DESCRIPTION Respond to PING on Select the interfaces on which you want the device to reply to incoming Ping requests. Do not respond to requests for unauthorized services. 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. Apply Reset 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. 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 132 Vantage CNM User's Guide