Why dual home?
Dual homing means having two separate independent connections to the Internet. Servers in this configuration have also been called bastion hosts and can include DNS servers which require multiple connections.
Benefits of dual homing can include:
• redundant Internet connection that essentially never fails
• faster connections through one ISP or the other for some destinations, such as other clients of those ISPs
• load balancing traffic to your Company network
• easier to enable more traffic through two connections than upgrading one connection to bigger bandwidth
• easier to create protection policies for different traffic through a specific ISP
Some companies require reliable internet access at all times as part of their business. Consider a doctor operating remotely who has their Internet connection fail — the consequences could easily be life or death.
Dual homing is extra expense for the second ISP connection, and more work to configure and maintain the more complex network topology.