ZyXEL Communications P-660HN-F1A, User Manual

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Chapter 18 Remote Management
P-660HN-F1A User’s Guide
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The following table describes the labels in this screen.
Table 89 Advanced > Remote Management > ICMP
LABEL DESCRIPTION
ICMP Internet Control Message Protocol is a message control and error-
reporting protocol between a host server and a gateway to the Internet.
ICMP uses Internet Protocol (IP) datagrams, but the messages are
processed by the TCP/IP software and directly apparent to the
application user.
Respond to
Ping on The P-660HN-F1A will not respond to any incoming Ping requests when
Disable is selected. Select LAN to reply to incoming LAN Ping requests.
Select WAN to reply to incoming WAN Ping requests. Otherwise select
LAN & WAN to reply to both incoming LAN and WAN Ping requests.
Do not respond
to requests for
unauthorized
services Select this option to prevent hackers from finding the P-660HN-F1A by
probing for unused ports. If you select this option, the P-660HN-F1A will
not respond to port request(s) for unused ports, thus leaving the unused
ports and the P-660HN-F1A unseen. If this option is not selected, the P-
660HN-F1A 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 P-660HN-F1A's
firewall rule checks before reaching this anti-probing mechanism.
Therefore if a firewall rule stops a probing packet, the P-660HN-F1A
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.
Apply Click this to save your changes.
Cancel Click this to restore your previously saved settings.