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Ip arp inspection trust

As explained in Acing the CCNA Exam: Volume 2 Advanced Networking and Security

ip arp inspection trust is a Cisco IOS interface configuration command that marks a switch port as trusted for Dynamic ARP Inspection.

ip arp inspection trust is a Cisco IOS interface-configuration command that marks a switch port as trusted for Dynamic ARP Inspection (DAI). DAI permits ARP messages received on trusted ports; it inspects messages on untrusted ports against the DHCP Snooping binding table. section 14.2.1 section 14.3

Apply the command with these operational rules:

  • All ports are untrusted by default when DAI is enabled; leave end-host ports untrusted. section 14.3
  • Trust ports connected to infrastructure devices such as routers and switches. section 14.2.1
  • Trust ports carrying devices with manually configured IP addresses, or define their IP–MAC mappings with an ARP ACL. section 14.3
  • Verify trust state and rate limits with show ip arp inspection interfaces. section 14.2.1

Configure and verify a trusted port

SW2(config)# interface g0/1 SW2(config-if)# ip arp inspection trust SW2(config-if)# do show ip arp inspection interfaces Gi0/1 Trusted None N/A Gi0/2 Untrusted 15 1 The command trusts Gi0/1, while Gi0/2 remains untrusted.

How Acing the CCNA Exam: Volume 2 Advanced Networking and Security covers it

How deep it goes
Defines syntax, defaults, placement guidance, verification, and filtering consequences, while deferring optional ARP validation details.
Examples
Uses SW2 GigabitEthernet0/1 configuration and show ip arp inspection interfaces output to demonstrate trust states.
What it assumes
Assumes DAI and DHCP Snooping concepts, including binding-table validation and trusted versus untrusted ports.
What you can do after
Operate/configure a DAI trusted interface and verify its trust state on Cisco IOS.
How it connects
Connects Dynamic ARP Inspection with DHCP Snooping, trusted ports, untrusted ports, and ARP ACLs.
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Related concepts

This explainer was generated by Manning's knowledge graph from the text of Acing the CCNA Exam: Volume 2 Advanced Networking and Security. The section links point to the parts of the book it draws on.