Defining and configuring named source-port filters

The named source-port filter command operates from the global configuration level.

Syntax:


[no] filter source-port named-filter <filter-name>

Defines or deletes a named source-port filter. The <filter-name > may contain a maximum of 20 alpha-numeric characters (longer names may be specified, but they are not displayed.) A filter-name cannot be a valid port or port trunk name.

The maximum number of named source-port filters that can be used is equal to the number of ports on a switch.

A named source-port filter can only be removed if it is not in use (use the show filter source-port command to check the status). Named source-port filters are not automatically deleted when they are no longer used.

Use the no option to delete an unused named source-port filter.

Syntax:


filter source-port named-filter <filter-name> drop <destination-port-list>

Configures the named source-port filter to drop traffic having a destination on the ports and/or port trunks in the <destination-port-list >. Can be followed by the forwardoption if you have other destination ports or port trunks previously set to drop that you want to change to forward.

For example: filter source-port named-filter <filter-name> drop <destination-port-list> forward <destination-port-list> .

The destination-port-list may contain ports, port trunks, and ranges (for example 3-7 or trk4-trk9) separated by commas.

Syntax:


filter source-port named-filter <filter-name> forward <destination-port-list>

Configures the named source-port filter to forward traffic having a destination on the ports and/or port trunks in the <destination-port-list>. Since “forward” is the default state for destinations in a filter, this command is useful when destinations in an existing filter are configured for “drop” and you want to change them to ”forward”. Can be followed by the dropoption if you have other destination ports set to forward that you want to change to drop.

For example: filter source-port named-filter <filter-name> forward <destination-port-list> drop <destination-port-list>

A named source-port filter must first be defined and configured before it can be applied. In the following example two named source-port filters are defined, web-only and accounting.

switch(config)# filter source-port named-filter web-only
switch(config)# filter source-port named-filter accounting

By default, these two named source-port filters forward traffic to all ports and port trunks.

To configure a named source-port filter to prevent inbound traffic from being forwarded to specific destination switch ports or port trunks, the dropoption is used. For example, on a 26-port switch, to configure the named source-port filter web-only to drop any traffic except that for destination ports 1 and 2, the following command would be used:

switch(config)# filter source-port named-filter
web-only drop 3-26

A named source-port filter can be defined and configured in a single command by adding the drop option, followed by the required destination-port-list.