Understanding Destination NAT

Destination NAT is the translation of the destination IP address of a packet entering the Juniper Networks device. Destination NAT is used to redirect traffic destined to a virtual host (identified by the original destination IP address) to the real host (identified by the translated destination IP address).

Note: When destination NAT is performed, the destination IP address is translated according to configured destination NAT rules and then security policies are applied.

Destination NAT allows connections to be initiated only for incoming network connections—for example, from the Internet to a private network. Destination NAT is commonly used to perform the following actions:

• Translate a single IP address to another address (for example, to allow a device on the Internet to connect to a host on a private network).
• Translate a contiguous block of addresses to another block of addresses of the same size (for example, to allow access to a group of servers).
• Translate a destination IP address and port to another destination IP address and port (for example, to allow access to multiple services using the same IP address but different ports).

The following types of destination NAT are supported:

• Translation of the original destination IP address to an IP address from a user-defined pool. This type of translation does not include Port Address Translation (PAT). If the original destination IP address range is larger than the address range in the user-defined address pool, any untranslated packets are dropped.
• Translation of the original destination IP address (and optional port number) to one specific IP address (and port number) from a user-defined pool.

Related Topics

• Junos OS Feature Support Reference for SRX Series and J Series Devices
• Destination NAT Configuration Overview
• Example: Configuring Destination NAT for Single Address Translation
• Example: Configuring Destination NAT for IP Address and Port Translation
• Example: Configuring Destination NAT for Subnet Translation
• NAT Overview
• Understanding Destination NAT Address Pools
• Understanding Destination NAT Rules