Help us improve your experience.

Let us know what you think.

Do you have time for a two-minute survey?




Hierarchy Level


Specify the Domain Name System (DNS) Application Layer Gateway (ALG) on the device.


  • disable—Disable the DNS ALG. By default, the DNS ALG is enabled. You can enable or disable the DNS ALG for both IPv4 and IPv6 mode.

  • doctoring—Configure DNS ALG doctoring.

    • none— Disable all DNS ALG doctoring.

    • sanity-check—Perform only DNS ALG sanity checks.

  • maximum-message-length—Set maximum message length (bytes).

    Range: 512 through 819.

    Default: 512.

  • oversize-message-drop—Configure to drop the oversized DNS packets.

  • traceoptions— Configure DNS ALG tracing options.

    • flag—Trace operation to perform.

      • all—Trace all events.

      • extensive—Display extensive amount of data.

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.

The tenant option is introduced in Junos OS Release 18.3R1.