How to create an exclusion from a DHCP lease

04/08/2021 98 21557

DESCRIPTION:

How to create an exclusion from a DHCP lease

RESOLUTION:

Resolution for SonicOS 7.X

This release includes significant user interface changes and many new features that are different from the SonicOS 6.5 and earlier firmware. The below resolution is for customers using SonicOS 7.X firmware.

You cannot add an exclusion to a DHCP lease scope per se. The workaround is to split the lease scope into a group of lease scopes, that would exclude the lease you want to make sure are not going to be assigned. 
To do so follow these steps,

1. Login to the SonicWALL Management Interface.
2. Navigate to NETWORK | System | DHCP Server | DHCP Server Lease Scopes.
3. Choose the scope, for this KB we have chosen the X0 Subnet and exclude the IP address 192.168.168.100 from the scope and create an additional scope in the same X0 subnet (192.168.168.0/24)
   
   
   
   
4. Edit the Scope as shown in the screenshot and click OK
   
   
   
   
5. Create an additional scope for the remaining IP addresses , the scope would look like the screenshot below.
   
   

Resolution for SonicOS 6.5

This release includes significant user interface changes and many new features that are different from the SonicOS 6.2 and earlier firmware. The below resolution is for customers using SonicOS 6.5 firmware.

You cannot add an exclusion to a DHCP lease scope per se. The workaround is to split the lease scope into a group of lease scopes, that would exclude the lease you want to make sure are not going to be assigned. 
To do so follow these steps

1. Login to the SonicWALL Management page.
2. Click Manage in the top navigation menu.
3. Navigate to System Setup | Network | DHCP Server
4. Choose the scope, for this KB we have choosen the X0 Subnet and exclude the IP address 192.168.1.100 from the scope and create an additional scope in the same X0 subnet (192.168.1.0/24)
   
   
5. Edit the Scope too and end IP address as shown in the screenshot and click on OK
   
   
6. Create an additional scope for the remaining IP addresses , the scope would look like the screenshot below.
   
   
   
   
   

Resolution for SonicOS 6.2 and Below

The below resolution is for customers using SonicOS 6.2 and earlier firmware. For firewalls that are generation 6 and newer we suggest to upgrade to the latest general release of SonicOS 6.5 firmware.

You cannot add an exclusion to a DHCP lease scope per se. The workaround is to split the lease scope into a group of lease scopes, that would exclude the lease you want to make sure are not going to be assigned. 
I attached a self explanatory screen shot of a lease scope split into 3 leases for a dynamic range on one interface X0 of my firewall.