SMC Networks SMC8150L2 manual Access Control List Commands, Access Control Lists

Access Control List Commands 4

Access Control List Commands

Access Control Lists (ACL) provide packet filtering for IP frames (based on address, protocol, or Layer 4 protocol port number) or any frames (based on MAC address or Ethernet type). To filter packets, first create an access list, add the required rules and then bind the list to a specific port.

Access Control Lists

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 ingress or egress packets against the conditions in an ACL one by one. A packet will be accepted as soon as it matches a permit rule, or dropped as soon as it matches a deny rule. If no rules match for a list of all permit rules, the packet is dropped; and if no rules match for a list of all deny rules, 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 protocol port number.

The following restrictions apply to ACLs:

•Each ACL can have up to 96 rules.

•However, due to resource restrictions, the average number of rules bound the ports should not exceed 20.

•This switch supports ACLs for ingress filtering only. You can only bind one IP ACL to any port for ingress filtering. In other words, only one ACL can be bound to an interface - Ingress IP ACL.

The order in which active ACLs are checked is as follows:

1.User-defined rules in the Ingress IP ACL for ingress ports.

2.Explicit default rule (permit any any) in the ingress IP ACL for ingress ports.

3.If no explicit rule is matched, the implicit default is permit all.

Table 4-33 Access Control Lists

Command Groups	Function	Page
IP ACLs	Configures ACLs based on IP addresses, TCP/UDP port number, and	4-90
	protocol type
MAC ACLs	Configures ACLs based on hardware addresses, packet format, and	4-95
	Ethernet type
ACL Information	Displays ACLs and associated rules; shows ACLs assigned to each port	4-99

4-89