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Hierarchy Level

Release Information

Statement introduced in Junos OS Release 12.1.


Configure algorithm-based allocation of blocks of destination ports. By specifying this method, you ensure that an incoming (source) IP address and port always map to the same destination IP address and port block, thus eliminating the need for logging address translations.


block-size—Maximum number of ports that can be allocated to a user.

If block-size is configured as zero, the method for computing the block size is as follows:

block-size = int(65412/ceil[(Number of subscribers/Number of IP addresses in the NAT pool)]).


64512 is derived from (65535 - 1023) because the regular port assignments start from 1024.

Number of subscribers is derived from the from clause of the applicable NAT rule.

Default: 256

Range: 0 through 32,000

include-boundary-addresses—(Optional) Specifies that the lowest and highest addresses (the network and broadcast addresses) in the source address range of a NAT rule should be translated when the NAT pool is used. If the source address has a prefix of /32, the lowest and highest address are automatically translated.

Required Privilege Level

interface—To view this statement in the configuration.

interface-control—To add this statement to the configuration.

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