Patch by Robert Scheck <robert@fedoraproject.org> for iftop >= 0.17, which
corrects the wrong synopsis. According to "--help", it's "-F net/mask", not
"-N net/mask", because "-N" is "don't convert port numbers to services".

--- iftop-0.17/options.c		2006-02-08 03:57:44.000000000 +0100
+++ iftop-0.17/options.c.synopsis	2010-07-10 00:02:49.000000000 +0200
@@ -237,7 +237,7 @@
     fprintf(fp,
 "iftop: display bandwidth usage on an interface by host\n"
 "\n"
-"Synopsis: iftop -h | [-npbBP] [-i interface] [-f filter code] [-N net/mask]\n"
+"Synopsis: iftop -h | [-npbNBP] [-i interface] [-f filter code] [-F net/mask]\n"
 "\n"
 "   -h                  display this message\n"
 "   -n                  don't do hostname lookups\n"