ZyXEL Communications Prestige 2602R Series, User Manual

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Prestige 2602R Series User’s Guide
Chapter 13 Firewall Configuration 165
13.11 Anti-Probing
If an outside user attempts to probe an unsupported port on your Prestige, an ICMP response
packet is automatically returned. This allows the outside user to know the Prestige exists. The
Prestige supports anti-probing, which prevents the ICMP response packet from being sent.
This keeps outsiders from discovering your Prestige when unsupported ports are probed.
Internet Control Message Protocol (ICMP) 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.
Click Firewall in the navigation panel and click Anti Probing to display the screen as shown.
SNMP-TRAPS (TCP/
UDP:162)
Traps for use with the SNMP (RFC:1215).
SQL-NET(TCP:1521) Structured Query Language is an interface to access data on many
different types of database systems, including mainframes, midrange
systems, UNIX systems and network servers.
SSDP(UDP:1900) Simple Service Discovery Protocol (SSDP) is a discovery service
searching for Universal Plug and Play devices on your home network
or upstream Internet gateways using DUDP port 1900.
SSH(TCP/UDP:22) Secure Shell Remote Login Program.
STRMWORKS(UDP:1558) Stream Works Protocol.
SYSLOG(UDP:514) Syslog allows you to send system logs to a UNIX server.
TACACS(UDP:49) Login Host Protocol used for (Terminal Access Controller Access
Control System).
TELNET(TCP:23) Telnet is the login and terminal emulation protocol common on the
Internet and in UNIX environments. It operates over TCP/IP networks.
Its primary function is to allow users to log into remote host systems.
TFTP(UDP:69) Trivial File Transfer Protocol is an Internet file transfer protocol similar
to FTP, but uses the UDP (User Datagram Protocol) rather than TCP
(Transmission Control Protocol).
VDOLIVE(TCP:7000) Another videoconferencing solution.
Microsoft RDP(TCP:3389) Microsoft's Remote Desktop Protocol allows you to access a computer
through the Internet in order to work with its files programs and
resources.
VNC(TCP:5900) Virtual Network Computing is a remote display system that allows you
to view a computer's 'desktop' environment through the Internet.
NTP(TCP/UDP:123) Network Time Protocol is used in synchronizing the time of computer
clocks.
Table 47 Predefined Services (continued)
SERVICE DESCRIPTION