Chapter 23 Remote Management Configuration

Figure 202 Remote Management: ICMP

The following table describes the labels in this screen.

Table 144 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

on

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

Select this option to prevent hackers from finding the ZyXEL Device by probing for

requests for

unused ports. If you select this option, the ZyXEL Device will not respond to port

unauthorized

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

services

unseen. By default this option is not selected and 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

 

mechanism before reaching this anti-probing mechanism. Therefore if the firewall

 

mechanism blocks a probing packet, the ZyXEL Device reacts based on the

 

corresponding firewall policy to 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.

 

 

23.10 SSH

You can use SSH (Secure SHell) to securely access the ZyXEL Device’s command line interface. Specify which interfaces allow SSH access and from which IP address the access can come.

Unlike Telnet or FTP, which transmit data in plaintext (clear or unencrypted text), SSH is a secure communication protocol that combines authentication and data encryption to provide secure encrypted communication between two hosts over an unsecured network. In the following figure, computer A on the Internet uses SSH to securely connect to the WAN port of the ZyXEL Device for a management session.

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P-2602HWLNI User’s Guide