--ipset=/<domain>[/<domain>...]/<ipset>[,<ipset>...]
Places the resolved IP addresses of queries for one or more domains in
the specified Netfilter IP set. If multiple setnames are given, then the
addresses are placed in each of them, subject to the limitations of an
IP set (IPv4 addresses cannot be stored in an IPv6 IP set and vice
versa). Domains and subdomains are matched in the same way as
--address.
These IP sets must already exist. See
ipset(8)
for more details.