+.fi
+.IP \(bu 2
+\fBListed\fR
+.P
+List the IP addresses contained within the given CIDRs.
+.P
+.nf
+.I $ hath listed <<< \(dq192.168.0.240/29\(dq
+192.168.0.240
+192.168.0.241
+192.168.0.242
+192.168.0.243
+192.168.0.244
+192.168.0.245
+192.168.0.246
+192.168.0.247
+.fi
+.IP \(bu 2
+\fBReversed\fR
+.P
+Perform reverse DNS (PTR) lookups on the IP addresses contained within
+the given CIDRs.
+.P
+.nf
+.I $ hath reversed <<< \(dq198.41.0.4/30\(dq
+198.41.0.4: a.root-servers.net.
+198.41.0.5:
+198.41.0.6: rs.internic.net.
+198.41.0.7:
+.fi
+.P
+The DNS lookups are usually the bottleneck for this mode, but we can
+perform them in parallel. Simply pass the number of threads to the GHC
+runtime on the command line; for example, the following will perform
+25 lookups in parallel:
+.P
+.nf
+.I $ hath reversed +RTS -N25 <<< \(dq198.41.0.4/24\(dq
+198.41.0.4: a.root-servers.net.
+198.41.0.5:
+198.41.0.6: rs.internic.net.
+\(pc\(pc\(pc
+.fi