AMX NXA-ENET24 manual Command Function Mask, Ip Acl

CLI (Command Line Interface)

IP ACL Commands (Cont.)

Command	Function
mask	Command Usage: Packets crossing a port are checked against all the
(IP ACL - Cont.)	rules in the ACL until a match is found. The order in which these packets
	are checked is determined by the mask, and not the order in which the ACL
	rules were entered.
	First create the required ACLs and ingress or egress masks before map-
	ping an ACL to an interface.
	If you enter dscp, you cannot enter tos or precedence. You can enter both
	tos and precedence without dscp.
	Masks that include an entry for a Layer 4 protocol source port or destina-
	tion port can only be applied to packets with a header length of exactly five
	bytes.
	Example: This example creates an IP ingress mask with two rules. Each
	rule is checked in order of precedence to look for a match in the ACL
	entries. The first entry matching a mask is applied to the inbound packet:
	Console(config)#access-list ip mask-precedence in
	Console(config-ip-mask-acl)#mask host any
	Console(config-ip-mask-acl)#mask 255.255.255.0 any
	Console(config-ip-mask-acl)#
	Example:
	This shows that the entries in the mask override the precedence in which
	the rules are entered into the ACL. In the following example, packets with
	the source address 10.1.1.1 are dropped because the “deny 10.1.1.1
	255.255.255.255” rule has the higher precedence according the “mask
	host any” entry:
	Console(config)#access-list ip standard A2
	Console(config-std-acl)#permit 10.1.1.0 255.255.255.0
	Console(config-std-acl)#deny 10.1.1.1 255.255.255.255
	Console(config-std-acl)#exit
	Console(config)#access-list ip mask-precedence in
	Console(config-ip-mask-acl)#mask host any
	Console(config-ip-mask-acl)#mask 255.255.255.0 any
	Console(config-ip-mask-acl)#
	Example:
	This shows how to create a standard ACL with an ingress mask to deny
	access to the IP host 171.69.198.102, and permit access to any others.
	Console(config)#access-list ip standard A2
	Console(config-std-acl)#permit any
	Console(config-std-acl)#deny host 171.69.198.102
	Console(config-std-acl)#end
	Console#show access-list
	IP standard access-list A2:
	deny host 171.69.198.102
	permit any
	Console#configure
	Console(config)#access-list ip mask-precedence in
	Console(config-ip-mask-acl)#mask host any
	Console(config-ip-mask-acl)#exit
	Console(config)#interface ethernet 1/1
	Console(config-if)#ip access-group A2 in
	Console(config-if)#end
	Console#show access-list
	IP standard access-list A2:
	deny host 171.69.198.102
	permit any
	Console#

214 NXA-ENET24 - Software Management Guide