How to increase the number of usable IPs on an interface

The SonicWall security appliance includes a DHCP (Dynamic Host Configuration Protocol) server to distribute IP addresses, subnet masks, gateway addresses, and DNS server addresses to your network clients. The most used configuration for dhcp server is the range from 192.168.1.2 - 192.168.1.254 with the subnet mask 255.255.255.0 ( /24 ) has 254 usable IP addresses. However there may be situations where you need more than 254 IP addresses on the same interface, that's where the subnet mask is important.

EXAMPLE:  For example subnet mask 255.255.254.0 ( /23 ) has 510 usable IP addresses , subnet mask 255.255.252.0 ( /22 ) has 1022 usable IP and so on.

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.

Complete the following steps to configure the SonicWall DHCP and LAN interface to give out more ip addresses on a SonicWall firewall (UTM) appliance running SonicOS Enhanced or Standard firmware.

Change Lan Interface

1. Click network bar on top.
2. Navigate to interfaces.
3. Select the interface that you want to change for example: X0.
4. Select edit this interface.
5. Then on the subnet mask change from 255.255.255.0 to for example 255.255.248.0 which give out 2046 usable IPs.
6. Then press ok.
   
   

Change DHCP lease scope

1. Click network bar on top.
2. Navigate to DHCP SERVER.
3. Click on DHCP SERVER LEASE SCOPE.
4. Select the X0 lease scope and click edit this entry.
5. On the subnet mask change from 255.255.255.0 to 255.255.248.0
6. After that press ok.
   
   

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.

Complete the following steps to configure the SonicWall DHCP and LAN interface to give out more ip addresses on a SonicWall firewall (UTM) appliance running SonicOS Enhanced or Standard firmware.

Change Lan Interface

1. Click Manage bar on top.
2. Navigate to Network | Interfaces.
3. Select the interface that you want to change for example: X0.
4. Select edit this interface.
5. Then on the subnet mask change from 255.255.255.0 to for example 255.255.248.0 which give out 2046 usable IPs.
6. Then press ok.
   
   

Change DHCP lease scope

1. Click Manage bar on top.
2. Navigate to Network | DHCP SERVER.
3. Click on DHCP SERVER LEASE SCOPE.
4. Select the X0 lease scope and click edit this entry.
5. On the subnet mask change from 255.255.255.0 to 255.255.248.0
6. After that press ok.