Debugging DHCP performance

Abstract

Dynamic Host Configuration Protocol (DHCP) was defined to facilitate automatic configuration of IP addresses and other network parameters to hosts in a network. Efficiency of DHCP's address management is especially important today in part due to proliferation of mobile devices with transient network access patterns and the consequent increased demand on transient IP addresses in open-access networks. Unfortunately, DHCP's flexible design makes it susceptible to a variety of misconfigurations. The focus of this work is, therefore, to evaluate the performance and vulnerabilities of DHCP in operational networks today. To this end, we developed a tool called DHCP-Watch that facilitates DHCP-related network debugging and enables better capacity planning. We used this tool to perform a first-of-its-kind detailed measurement study of DHCP performance in operational university campus networks. Our measurements revealed various trends of IP address usage. Additionally, we discovered frequent anomalous operations due to network misconfigurations and presence of misbehaving hosts.