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Hierarchy Level


Prevent the SYN-ACK-ACK attack, which occurs when the attacker establishes multiple telnet sessions without allowing each session to terminate. This behavior consumes all open slots, generating a denial-of-service (DoS) condition.


threshold number — Number of connections from any single IP address.

  • Range: 1 through 250,000

  • Default: 512

Required Privilege Level

security—To view this statement in the configuration.

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

Release Information

Statement introduced in Junos OS Release 8.5; support.