bidentd(8) on Linux
The text a0feada890cb, as Debian 5.0 (Lenny), Debian 4.0 (Etch), Debian 3.1 (Sarge) shipped it.
Bisqwit's TCP/IP Identification Protocol daemon
Flags it lists
-
-q -
-qq -
-v -
-vv -
-vvv