Multihoming enables an interface to assume multiple IP addresses on the same network. Multihoming can be used for all IP networks bound to a router, whether the networks are bound to on the same interface or different interfaces. The most common use of multiple addresses on the same network is to enable a Web server to operate as though it is several Web servers. One application is to use each secondary IP address to point to a different Web page on the same Web server, depending on the Domain Name System (DNS) name that is used to reach the server.

Multihoming is also commonly used with Network Address Translation (NAT), the proxy server, and the Virtual Private Network (VPN). In all cases, the secondary IP address can be configured on the same interface that has the primary IP address, or the secondary address can be configured on a different interface. When there are multiple existing interfaces, the secondary address is associated with the interface that is bound to the network that uses the same address. If the secondary address is not valid on any of the networks bound to existing interfaces, the address is rejected and an error message is produced.

When multihoming is used with the proxy server, VPN or NAT, the secondary addresses must be configured manually as described in Novell Internet Access Server 4.1 Routing Configuration.