permit ip host

Creates a rule in an Address Resolution Protocol (ARP) ACL that permits ARP messages from a host specified by both IP and MAC addresses.

Syntax

permit ip host sender-ip mac host sender-mac-address

no permit ip host sender-ip mac host sender-mac-address

Command Default

No permit rules are defined.

Parameters

sender-ip: Specifies the sender IP address.
mac host sender-mac-address: Specifies the sender MAC address, in hexadecimal format.

Modes

ARP ACL configuration mode

Usage Guidelines

On untrusted interfaces of DAI-enabled VLANs, incoming ARP packets from permitted IP/MAC addresses are accepted only if all of the following steps were performed:

Create the ACL, using the arp access-list command.
In the ACL, create one or more rules, using the permit ip host command. Each rule specifies an IP/MAC address-pair.
Apply the ACL to one or more VLANs, using the ip arp inspection filter command.
Enable DAI on such VLANs, using the ip arp inspection command.

This command is also used to implement ARP Guard. ARP Guard is supported only on devices based on the Extreme 8820, SLX 9740, SLX 9640, and SLX 9540 devices only.

The no form of the command removes the permit rule from the ACL.

Examples

The following example defines a permit ip host rule in an ARP ACL, applies the ACL to a VLAN, and enables DAI on that VLAN.

device# configure terminal
device(config)# arp access-list arp_acl_1
device(config-arp-acl)# permit ip host 1.1.1.1 mac host 0020.2222.2222
device(config-arp-acl)# permit ip host 1.1.1.2 mac host 0020.2222.2223
device(config-arp-acl)# exit

device(config)# vlan 200
device(config-vlan-200)# ip arp inspection filter arp_acl_1
device(conf-vlan-200)# ip arp inspection

The following example creates a permit ip host rule within the arp access-list command.

device# configure terminal
device(config)# arp access-list host2 permit ip host 1.1.1.1 mac host 0000.0011.0022

The following example creates an ARP ACL, creates permit ip host rules within, and applies it to an interface. This is the first stage of ARP Guard implementation.

device# configure terminal
device(config)# arp access-list arp_acl_2
device(config-arp-acl)# permit ip host 1.1.1.1 mac host 0020.2222.2222
device(config-arp-acl)# permit ip host 1.1.1.2 mac host 0020.2222.2223
device(config-arp-acl)# exit

device(config)# interface ethernet 1/2
device(conf-if-eth-1/2)# switchport
device(conf-if-eth-1/2)# ip arp inspection filter arp_acl_2

Note

At this point, ARP Guard is not yet enabled. For more information, see the "ARP Guard" section of the Extreme SLX-OS Layer 3 Routing Configuration Guide.