&*Warning 3*&: Do not use an IPv4-mapped IPv6 address for a key; use the
IPv4, in dotted-quad form. (Exim converts IPv4-mapped IPv6 addresses to this
notation before executing the lookup.)
+
+.new
+One option is supported, "ret=full", to request the return of the entire line
+rather than omitting the key porttion.
+Note however that the key portion will have been de-quoted.
+.wen
+
.next
.cindex lookup json
.cindex json "lookup type"