Motorola Netopia 7000, Руководство администратора

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Administrator’s Handbook
166
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 por t number specified in the filter with the packet’s por t number.
• Not Equal To:
For the filter to match, the packet’s por t number cannot equal the por t number specified
in the filter.
•
Less Than: For the filter to match, the packet’s por t number must be less than the por t number speci-
fied in the filter.
• Less Than or Equal:
For the filter to match, the packet’s por t number must be less than or equal to the
por t number specified in the filter.
•
Equal: For the filter to match, the packet’s por t number must equal the por t number specified in the fil-
ter.
• Greater Than:
For the filter to match, the packet’s por t number must be greater than the por t number
specified in the filter.
•
Greater Than or Equal: For the filter to match, the packet’s por t number must be greater than or equal
to the por t number specified in the filter.
Other filter attributes
There are three other attributes to each filter:
•
The filter’s order (i.e., priority) in the filter set
•
Whether the filter is currently active
•
Whether the filter is set to for ward packets or to block (discard) packets
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