Failover without the fuss

Without failover, DHCP can be a single point of failure on your network. If you have a single server and it becomes unavailable, clients will be unable to request or renew IP address leases. As your reliance on your network grows, this disruption to DHCP becomes less tolerable.

To achieve failover your options have been limited to:

  • a high-end DDI solution in a grid-like deployment, or
  • an open source solution with limitations and high Total Cost of Ownership

The most popular solution for DHCP – Windows Server – has historically been limited in its failover capabilities:

  • Active-Passive redundancy would introduce a storage Single Point of Failure
  • Active-Active would ensure that a DHCP service remained available in the event of one server failing, but was unable to provice IP Address Continuity
  • Recent updates are limited to IPv4 address spaces

Similarly, Cisco routers and ISC's DHCPd have limited failover functionality – implementation requires expert DHCP knowledge and complicated workarounds.

DNSBOX makes it easy to set up and deploy a failover unit for redundancy. DNSBOX200 failover pairs share configuration, ensuring that they never 'disagree' about the network. They also dynamically share available addresses, and information about current leases.

DNSBOX failover be set up in a few simple clicks with options to suit different network topologies and requirements.

Active-Active Mode

The pool of available addresses is split between two active DHCP servers.

A diagram illustrating Active-Active failover mode with three client computers and two DNSBOXes between the computers and switch/router/cloud.

Active-Passive Mode

Achieved by clustering a pair of DHCP servers on a single virtual IP address. A passive server copies information about the leases distributed by the active server in real time.

A diagram illustrating Active-Passive failover mode with three client computers and one active DNSBOX, connected to a passive DNSBOX, between the computers and switch/router/cloud.
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