SMC Networks 6724AL2, Management Manual

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Access Control List Commands
Access Control Lists (ACL) provide packet filtering for IP frames (based
on address, protocol, TCP/UDP port number or TCP control code) or
non-IP frames (based on MAC address or Ethernet type). To filter
incoming packets, first create an access list, add the required rules, and
then bind the list to a specific port.
An ACL is a sequential list of permit or deny conditions that apply to IP
addresses, MAC addresses, or other more specific criteria. This switch tests
incoming packets against the conditions in an ACL one by one. If a list
contains all permit rules, a packet will be accepted as soon as it passes any
of the rules. If a list contains all deny rules, then a packet will be rejected as
soon as it fails any one of the rules. In other words, if no rules match for a
permit list, the packet is dropped; and if no rules match for a deny list, the
packet is accepted.
There are three filtering modes:
• Standard IP ACL mode (STD-ACL) filters packets based on the source
IP address.
• Extended IP ACL mode (EXT-ACL) filters packets based on source
or destination IP address, as well as protocol type and TCP/UDP port
number. If the TCP protocol type is specified, then you can also filter
packets based on the TCP control code.
• MAC ACL mode (MAC-ACL) filters based on the source, destination
MAC address and the Ethernet frame type (RFC 1060).
Note:
An access list can only contain all permit rules or all deny rules. In
other words, for performance reasons, you cannot mix permit and deny
rules in the same list.