Neighbors (ARP-NDP): Add Static neighbor - Is the static arp entry have limit

Hello Munish thakur,

Thank you for reaching out to the community, by limit you mean how many static neighbor ship SFOS can maintain? If yes what is the use case here are you facing any challenges ?

yes i need to do 

static arp enrty for every user statically 

i do have 1500 user in my network 

May we know why you need to add static arp entry for all the 1500 users in your network ?
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You can use API though - https://docs.sophos.com/nsg/sophos-firewall/18.5/API/index.html
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My admin want to bind ip address with mac address of user without user authentication 

That the reason i m asking this 

In that scenario, you do not need bother about the static neighbor table under the network > neighbor [ARP-NDP] 
You should refer the following: Bind MAC address to a user- https://support.sophos.com/support/s/article/KB-000035643?language=en_US

> Register a user - https://docs.sophos.com/nsg/sophos-firewall/18.5/Help/en-us/webhelp/onlinehelp/AdministratorHelp/Authentication/Users/AuthenticationUserRegister/index.html#
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Under the SYSTEM > Hosts and services > MAC host: You can add the MAC host entries there !!
additionally: you can also refer the MAC base rule: https://support.sophos.com/support/s/article/KB-000035664?language=en_US 

In that scenario, you do not need bother about the static neighbor table under the network > neighbor [ARP-NDP] 
You should refer the following: Bind MAC address to a user- https://support.sophos.com/support/s/article/KB-000035643?language=en_US

> Register a user - https://docs.sophos.com/nsg/sophos-firewall/18.5/Help/en-us/webhelp/onlinehelp/AdministratorHelp/Authentication/Users/AuthenticationUserRegister/index.html#
============

Under the SYSTEM > Hosts and services > MAC host: You can add the MAC host entries there !!
additionally: you can also refer the MAC base rule: https://support.sophos.com/support/s/article/KB-000035664?language=en_US