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+# (S)NTP - (Simple) Network Time Protocol - RFCs 1305 and 2030
+# Pattern quality: good veryfast overmatch
+#
+# This pattern is tested and is believed to work. If this does not work
+# for you, or you believe it could be improved, please post to
+# l7-filter-developers@lists.sf.net . Subscribe at
+# http://lists.sourceforge.net/lists/listinfo/l7-filter-developers
+
+# client|server
+# Requires the server's timestamp to be in the present or future (of 2005).
+# Tested with ntpdate on Linux.
+# Assumes version 2, 3 or 4.
+
+# Note that ntp packets are always 48 bytes, so you should match on that too.
+
+ntp
+^([\x13\x1b\x23\xd3\xdb\xe3]|[\x14\x1c$].......?.?.?.?.?.?.?.?.?[\xc6-\xff])