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Configuring ACLs
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NXA-ENET24 - Software Management Guide
Configuring ACLs
Overview
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.
Command Usage
The following restrictions apply to ACLs:
Each ACL can have up to 32 rules.
The maximum number of ACLs is also 32.
However, due to resource restrictions, the average number of rules bound to the ports should not
exceed 20.
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.
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 switch does not support the explicit “deny any” rule for the egress IP ACL or the egress MAC
ACLs. If these rules are included in ACL, and you attempt to bind the ACL to an interface for
egress checking, the bind operation will fail.
The order in which active ACLs are checked is as follows:
1. User-defined rules in the Egress MAC ACL for egress ports.
2. User-defined rules in the Egress IP ACL for egress ports.
3. User-defined rules in the Ingress MAC ACL for ingress ports.
4. User-defined rules in the Ingress IP ACL for ingress ports.
5. Explicit default rule (permit any) in the ingress IP ACL for ingress ports.
6. Explicit default rule (permit any) in the ingress MAC ACL for ingress ports.
7. If no explicit rule is matched, the implicit default is permit all.
Setting the ACL Name and Type
Use the ACL Configuration page to designate the name and type of an ACL.
Command Attributes
Command Attributes
• Name: Name of the ACL. (Maximum length: 16 characters)
•Type: There are three filtering modes:
• Standard: IP ACL mode that filters packets based on the source IP address.
• Extended: IP ACL mode that filters packets based on source or destination IP
address, as well as protocol type and protocol port number. If the “TCP”
protocol is specified, then you can also filter packets based on the TCP
control code.
• MAC: MAC ACL mode that filters packets based on the source or destination
MAC address and the Ethernet frame type (RFC 1060).