This article is about how to fix the error "Error: the subnet mask must be wider than 255.255.252.0" when configuring a WLAN interface on the Firewall.
When configuring the WLAN interface on the firewall the UI shows the error message as "Error: The Subnet Mask must be wider than 255.255.252.0." The error while configuring is because of the value specified on SonicPoint/SonicWave Limit on the Interface.
SonicPoint/SonicWave Limit specifies the maximum number of SonicPoints allowed on this interface. This value determines the highest subnet mask you can enter in the Subnet Mask field.
To overcome the error change the SonicPoint /SonicWave Limit to 128 when using the network 192.168.10.1 with a subnet mask of 255.255.255.0.
Maximum subnet mask sizes allowed shows the subnet mask limit for each SonicPoint/SonicWave Limit selection and the number of DHCP leases available on the interface if you enter the maximum allowed subnet mask.
Available Client IPs assumes 1 IP for the firewall gateway interface, in addition to the presence of the maximum number of SonicPoints allowed on this interface, each consuming an IP address.