With the release of NetWare® 6.5, Novell® enhanced the TCP/IP stack to support virtual IP addresses. This feature is another high-availability offering that enables administrators to easily manage the name-to-IP address associations of business services. It complements the existing load balancing and fault tolerance features of the TCP/IP stack and enhances the availability of servers that reside on multiple subnets.
A virtual IP address is an IP address that is bound to a virtual Network Interface Card (NIC) and is driven by a new virtual driver named vnic.lan. As the name suggests, this virtual NIC is a purely virtual entity that has no physical hardware counterpart. A virtual NIC can be thought of as a conventional TCP/IP loopback interface with added external visibility. Virtual IP addresses can also be thought of as conventional loopback addresses with the 127.0.0.0 IP network constraint relaxed. A server with a virtual NIC and a virtual IP address acts as an interface to a virtual internal IP network that contains the server as the one and only host.
Regardless of their virtual nature, virtual IP addresses and virtual NICs behave like physical IP addresses and physical NICs, and they are similarly configured by using either the INETCFG server-based utility or the Novell Remote Manager Web-based utility.