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[ScreenOS] What is the default ARP timeout of a Netscreen firewall & is it a configurable parameter?



Article ID: KB6771 KB Last Updated: 15 Dec 2017Version: 5.0
This article describes the default 'ARP timeout' on NetScreen firewalls. It also provides the configuration on how to change it.


  • It should be noted that in certain versions of ScreenOS, the output from get arp'  command truncates the age column resulting in a remaining age for that entry that is incorrect.
  • Only the four right most digits can be viewed.
  • The default is 1200 seconds (20 mins)
  • The max is 65535 seconds (approximately 18 hours). The strange number results from it being the maximum possible from a 16 bit integer field.
  • The minimum is 1 second.
  • The value can be modified by using the 'set arp age' command. Following configuration example changes the arp cache timeout to 120 seconds.
    set arp age 120
Modification History:
2017-12-07: Article reviewed for accuracy. Article is correct and complete. Also merged content of KB25401 in it as both these KBs were providing the same information.
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