Get full access to Cisco Routers for the Desperate, 2nd Edition and 60K+ other titles, with a free 10-day trial of O'Reilly.

There are also live events, courses curated by job role, and more.

Start your free trial

Viewing ARP Caches and Finding Hosts

ARP, the Address Resolution Protocol, allows devices on an Ethernet to find each other. Each device on an Ethernet network has a MAC (Media Access Control) address, also known as a hardware address. A MAC address is a unique 48-bit hexadecimal number. Any Cisco device will display the ARP table with the show arp command.

  Switch>sho arp
  Protocol  Address          Age (min)  Hardware Addr   Type   Interface
 Internet  10.184.0.243   14        0019.b9f0.ace1  ARPA  Vlan1 Internet 10.184.0.248 207 0004.23ce.45d7 ARPA Vlan1 Internet 10.184.0.254 ...

Get Cisco Routers for the Desperate, 2nd Edition now with the O’Reilly learning platform.

O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.

Start your free trial

Don’t leave empty-handed

Get Mark Richards’s Software Architecture Patterns ebook to better understand how to design components—and how they should interact.

It’s yours, free.

Get it now

Check it out now on O’Reilly

Dive in for free with a 10-day trial of the O’Reilly learning platform—then explore all the other resources our members count on to build skills and solve problems every day.

Start your free trial Become a member now