ZyXEL Communications P-660 series Guia do Utilizador descarregar pdf (Página 173)

Chapter 13 Remote Management Configuration

P-660R-F1 Series User’s Guide

173

13.8 Configuring ICMP

To change your ZyXEL Device’s security settings, click Advanced > Remote MGMT > ICMP. The

screen appears as shown.

If an outside user attempts to probe an unsupported port on your ZyXEL Device, an ICMP response

packet is automatically returned. This allows the outside user to know the ZyXEL Device exists.

Your ZyXEL Device supports anti-probing, which prevents the ICMP response packet from being

sent. This keeps outsiders from discovering your ZyXEL Device when unsupported ports are probed.

Figure 105 Remote Management: ICMP

The following table describes the labels in this screen.

Table 67 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

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.

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