Configure the size of the IPv4 flow table in units of 256K entries.
Prior to Junos OS Release 16.1R1 and 15.1F2, any changes in the configured size of the flow table initiates an automatic reboot of the FPC, and we recommend that you run this command in a maintenance window.
Starting with Junos OS Release 16.1R1 and 15.1F2, by default, the software allocates 1K entries for IPv4 flow tables. To allocate fifteen 256K IPv4 flow tables, the former default, you can enter this configuration from the  hierarchy level:
Starting with Junos OS Release 17.3R1, the maximum number of 256K flow entries that you can configure for IPv4 flow tables and IPv6 flow tables is 256 on MPC5Es and MPC6Es with with 4 GB DDR3 memory or higher. The maximum number of 256K flow entries that you can configure for IPv4 flow tables and IPv6 flow tables is 245 on MPC5Es and MPC6Es with DDR3 memory lower than 4 GB.
 user@router# set chassis fpc slot-number inline-services flow-table-size ipv4-flow-table-size 15
Range: 1 through 245
Default: 1024 (1K)—Starting with Junos OS Release 16.1R1 and 15.1F2
Default: 3,932,160 (3840K)—Prior to Junos OS Release 16.1R1 and 15.1F2
Required Privilege Level
interface—To view this statement in the configuration.
interface-control—To add this statement to the configuration.