Edge Products ES3528-WDM - Manual (Page 129)

8-1
Chapter 8: Access Control Lists
Access Control Lists (ACL) provide packet filtering for IP frames (based on address,
protocol, Layer 4 protocol port number or TCP control code), or any frames (based
on MAC address or Ethernet type). To filter incoming packets, first create an access
list, add the required rules, specify a mask to modify the precedence in which the
rules are checked, and then bind the list to a specific port.
Configuring 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.
You must configure a mask for an ACL rule before you can bind it to a port or set the
queue or frame priorities associated with the rule. This is done by specifying masks
that control the order in which ACL rules are checked. The switch includes two
system default masks that pass/filter packets matching the permit/deny rules
specified in an ingress ACL. You can also configure up to seven user-defined masks
for an ingress or egress ACL. A mask must be bound exclusively to one of the basic
ACL types (that is, Ingress IP ACL, Egress IP ACL, Ingress MAC ACL, or Egress
MAC ACL), but a mask can be bound to up to four ACLs of the same type.
The following filtering modes are supported:
• 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. If the TCP protocol
is specified, packets can also be filtered based on the TCP control code.
• MAC ACL mode (MAC-ACL) filters packets based on the source or destination
MAC address and the Ethernet frame type (RFC 1060).
Command Usage
The following restrictions apply to ACLs:
• The switch supports ACLs for both ingress and egress filtering. However, only one
IP ACL and one MAC ACL can be bound to any port for ingress filtering, and one
IP ACL and one MAC ACL to any port for egress filtering. In other words, only four
ACLs can be bound to an interface – Ingress IP ACL, Egress IP ACL, Ingress MAC
ACL and Egress MAC ACL.
• When an ACL is bound to an interface as an egress filter, all entries in the ACL
must be deny rules. Otherwise, the bind operation will fail.
• The maximum number of ACLs is:
Fast Ethernet ports - 157 rules, 4 masks shared by 8-port groups
Gigabit Ethernet ports - 29 rules, 4 masks