test_tbl=# CREATE INDEX idx_network_info_network_gist
test_tbl-#   ON network_info USING gist(network);
ERROR:  data type cidr has no default operator class for access method "gist"
HINT:  You must specify an operator class for the index or define a default operator class for the data type.

test_tbl=# CREATE INDEX idx_ipaddr_info_ipaddr_gist
test_tbl-#   ON ipaddr_info USING gist(ipaddr);
ERROR:  data type inet has no default operator class for access method "gist"
HINT:  You must specify an operator class for the index or define a default operator class for the data type.