--rev-server=<ip-address>[/<prefix-len>][,<server>][#<port>][@<interface>][@<source-ip>[#<port>]]

This is functionally the same as --server, but provides some syntactic sugar to make specifying address-to-name queries easier. For example --rev-server=1.2.3.0/24,192.168.0.1 is exactly equivalent to --server=/3.2.1.in-addr.arpa/192.168.0.1 Allowed prefix lengths are 1-32 (IPv4) and 1-128 (IPv6). If the prefix length is omitted, dnsmasq substitutes either 32 (IPv4) or 128 (IPv6).