Neighbors (ARP-NDP): Add Static neighbor - Is the static limit only 16 entries?


SFOS 17.5.4 MR-4-1

What is the limit of the static neighbor table?

The reason I ask is that it only seems to let me at 16 static entries. When trying to add the 17th entry it just gives me the spinning image for a second then stays on the add screen without actually adding it to the table.

  • no one might know the exact hard limit of this one, supposing that this might be a dev item. 

  • I opened a support case. I will follow-up and post my findings.

  • The XG doesn't have an issue with adding more then 16 static ARP entries, it does however have a limit of adding 16 entries with the same MAC address when checking the "Add as a trusted MAC address to prevent a spoofing attempt."

    When the box is checked it adds the IP address to the MAC address entry in "Spoof protection trusted MAC".

    These entries are limited to 16 IPs per MAC. Sophos support says this is functioning as designed.


    A. add the entry without the spoof protection.

    B. If the entry was going to be handled by the XG, just add it as an Alias of the interface with the MAC you were trying to add it to.

    I think both options will forgo spoof protection if you have more then 16 IP addresses on one MAC.

    In my case both scenarios will work, but since the XG has the alias option, it is probably best to use it that way to cut down on confusion when working with others in the community or support.