from
21/tcp is open, was filtered.
23/tcp is open, was filtered.
80/tcp is open, was filtered.
8701/tcp is filtered, was open.
to
-21/tcp filtered
+21/tcp open ftp Netgear broadband router ftpd 1.0
-23/tcp filtered
+23/tcp open telnet Netgear broadband router admin telnetd
-80/tcp filtered
+80/tcp open http Embedded Allegro RomPager webserver 4.07 UPnP/1.0 (ZyXEL ZyWALL 2)
-8701/tcp open unknown
+8701/tcp filtered
happens when a host was scanned in the A scan but wasn't scanned in the B scan.
I previously had it ignore such changes using the logic that the diff should be
like scan aggregation: no new information means no state change. But I think
it's more useful to see those changes in which hosts were scanned.
This is analogous to r10263, which did the same thing for port state changes.
