Netopia 2200 - Manual (Page 158)

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Port numbers
A filter can also match a packet’s por t number attributes, but only if the filter’s protocol
type is set to TCP or UDP, since only those protocols use por t numbers. The filter can be
configured to match the following:
• The source por t number (the por t on the sending host that originated the packet)
• The destination por t number (the por t on the receiving host that the packet is destined
for)
By matching on a por t number, a filter can be applied to selected TCP or UDP ser vices,
such as Telnet, FTP, and World Wide Web. The following tables show a few common ser-
vices and their associated por t numbers:
Port number comparisons
A filter can also use a comparison option to evaluate a packet’s source or destination por t
number. The comparison options are:
• No Compare: No comparison of the port number specified in the filter with the
packet’s por t number.
• Not Equal To: For the filter to match, the packet’s port number cannot equal the port
number specified in the filter.
Internet service TCP port Internet service TCP port
FTP 20/21 Finger 79
Telnet 23 World Wide Web 80
SMTP (mail) 25 News 144
Gopher 70 rlogin 513
Internet service UDP port Internet service UDP port
Who Is 43 TFTP 69
World Wide Web 80 who 513
SNMP 161