#4 Unknown flags in handshake

[oliver]

Every few handshakes an unknown flag is reported. It
happens so often that you might wonder that maybe it's
an 'updated' handshake.

The flags in question are:
Unknown flags in handshake: ffffff8000000000000000
Unknown flags in handshake: 6578000000000000

[Maarten Vanraes]

Logged In: YES
user_id=552626

These are caused by clients that don't follow the protocol exactly or have
additions to the protocol.

[Leon Kos]

Logged In: YES
user_id=980076

Here is my brief count of log file:
$ tr '\r' '\n' < current.log |grep flags |sort|uniq -c
156 Unknown flags in handshake: 0000000000100000
986 Unknown flags in handshake: 6578000000000000
58 Unknown flags in handshake: ffffff8000000000000000

To see which flags should be considered as important to handle!