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[ScreenOS] What is a VIP used for?

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What is a VIP and what are the common scenarios where VIP can be used?

  • How to take an existing IP address and port and forward it to an internal IP address and port
  • What is a VIP?
  • What is a Virtual IP?

Virtual IPs (VIP) are one to many mappings of IP address that distinguish traffic based on port number to determine what IP address to send the traffic to.  A common application of VIPs is to have one public IP address represent the Web server, email server and FTP server, each of which has a unique private IP address.  This sharing of one external IP address provides a good way to conserve public IP addresses.

A Virtual IP can also be used for port forwarding.  For example, assume you want to open web access to the Internet to a web server you have that is listening on port 80.  However, due to security concerns, you only want users to be accessing this site using port 8080.  You can use Virtual IP to accomplish this.  Specify the Virtual IP, which is the IP address that the Internet will be using to access the web site.  Then, specify the external port, and this combination of external IP and port will be mapped to an internal IP address and port.

For more information on VIP, see the following Juniper document: Concepts & Examples, ScreenOS Reference Guide, Address Translation ("Virtual Addresses," starting on page 79).

Modification History:
2019/02/22: Minor, non-technical, modifications. Removed EOL products
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