ZyXEL Communications P-2802H-I Series, User Manual

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Chapter 19 Remote Management Configuration
P-2802H(W)(L)-I Series User’s Guide
270
Figure 161 Remote Management: ICMP
The following table describes the labels in this screen.
Table 111 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 ZyXEL Device 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 ZyXEL Device by probing for
unused ports. If you select this option, the ZyXEL Device will not respond to port
request(s) for unused ports, thus leaving the unused ports and the ZyXEL Device
unseen. If this option is not selected, the ZyXEL 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 ZyXEL Device's firewall rule
checks before reaching this anti-probing mechanism. Therefore if a firewall rule
stops a probing packet, the ZyXEL 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.
Apply Click Apply to save your customized settings and exit this screen.
Cancel Click Cancel to begin configuring this screen afresh.