Adding IP Blocks/Ranges
Select a sending server, and conveniently add IP or IP blocks by following the set pattern. List multiple commas separated IPs, or add a block but just providing the range separated by a hyphen 192.168.0.10-25. While adding, provide FDNS domain and a preferred prefix for the FDNS will eventually proposes FDNS for all the IPs in the range. So this doesn’t only add the IPs belonging to certain server, it also configures a domain that each IP would eventually resolve to.