ZyXEL Communications ZyXEL ZyWALL P1, User Manual

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ZyWALL P1 User’s Guide
118 Chapter 7 Firewall Screens
7.9 Anti-Probing
If an outside user attempts to probe an unsupported port on your ZyWALL, an ICMP response
packet is automatically returned. This allows the outside user to know the ZyWALL exists.
The ZyWALL supports anti-probing, which prevents ZyWALL ICMP response packet from
being sent. This keeps outsiders from discovering your ZyWALL 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 , then the Anti-Probing tab to open the screen.
SFTP(TCP:115) Simple File Transfer Protocol.
SMTP(TCP:25) Simple Mail Transfer Protocol is the message-exchange standard for
the Internet. SMTP enables you to move messages from one e-mail
server to another.
SNMP(TCP/UDP:161) Simple Network Management Program.
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 UDP 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.
Table 34 Predefined Services (continued)
SERVICE DESCRIPTION