Application servers and network devices use IP addresses to identify clients. The application server often caches information about clients coming from the same machine. Network routers try to cache source and destination information to optimize throughput. If many users have the same IP address, both the server and the routers try to optimize. Since Vusers on the same load generator have the same IP address, server and router optimizations do not reflect real-life situations.
LoadRunner Professional's Multiple IP Address feature enables Vusers running on a single load generator to be identified by many IP addresses (this is known as IP spoofing). The server and router recognize the Vusers as coming from different load generators and as a result, the testing environment is more realistic.
This feature can be implemented on Windows and Linux platforms with the following protocols: DNS, IMAP, Oracle NCA, Oracle-Web, POP3, RTE, SAP-Web, Siebel-Web, SMTP, Web - HTTP/HTML, Web Services, and Windows Sockets.