Additional IP pools
How to do this in pfsense ?
I just change the netmask to /23 , then this will increase the available ip pool , i just add the ip range at the dhcp server ?
no more additional settings on the dns or firewall / nat ?
The DHCP pool is a separate setting on the DHCP page. Address range has nothing to do with DNS. You configure the DNS records to match the host address. NAT is only a factor, if you have rules for incoming traffic.