DHCP Authorized ARP


You work as a network engineer for a Hotel offering Internet access for a hourly rate. Recently you notice that some customers have been spoofing MAC and IP addresses to get free access by pretending they are another customer. After kicking them out of the hotel you decide to make some changes to DHCP so this can’t happen anymore.


  • The IP address for router DHCP has been preconfigured for you.
  • Configure router DHCP as a DHCP server for network /24.
  • Configure router DHCP so whenever router CLIENT sends a DHCP Discover it will install a secure ARP entry.
  • Configure router DHCP so it sends ARP messages every 60 seconds to ensure router CLIENT is still there.
  • Configure router SPOOFER with an IP address and see how things have changed.




DHCP Authorized ARP

Video Solution:

Configuration Files

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Written by René Molenaar - CCIE #41726

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About the Author: Rene Molenaar

René - CCIE #41726 is the creator of GNS3Vault.com where he shares CCNA, CCNP and CCIE R&S labs. He also blogs about networking on http://networklessons.com