V0.2  Oct.17, 2003  JBW
  Added new doormand.cf records 'connection_delay_1' & 'connection_delay_2'.
  Updated to autoconf 2.57 & automake 1.7.8
  Fixed md5 library search for Debian.
  Fixed db function calls for db version 2.

V0.3  Oct.22, 2003  JBW
  Added more stringent packet-validity checks to doormand.c
  Changed log-level of valid packet receipt events
  Improved method of supplying replacement functions
  Fixed zombie problem; (had forgotten wait() call...*blush*...)
  Fixed -many- bugs in use of db version 2 functions
  Added support for db version 1; can now accept versions 1-4.
  Fixed several problems in configure.ac
  Added "-i ipaddress" option to knock.c

V0.4  Nov.03, 2003  JBW
  Changed semantics of "-D" option in doormand; now means "Debug"
  Fixed bug in "-h" option in knock
  Added iptables firewall scripts; renamed ipchains scripts
  Fixed doormand hang on reconfigure after SIGHUP.

V0.5  July 2, 2004  JBW
  Added an 'Enter secret' prompt to knock.c if no secret is specified
  in either .knockcf or on command line
  Removed use of Berkeley DB; using crude (but fast enough) binary search now.
  Changed syntax of 'guestlist' configuration file
  Fixed several small bugs in knock & doormand

v0.5.1 July 3, 2004  JBW
  Removed 'maskbits' config record for knock client. (Never was actually
  useful.. just a stupid design blunder.)  Changed code to match in
  doormand.c
  Cleaned up many discrepancies in documentation

v0.6   July 14, 2004  JBW
  Fixed bug in knock.exe, which under Win9x, would cause stubborn
  'incorrect secret' errors.
  Removed 'gettimeofday.c' from replacement functions
  Added '-U' option to Windows version of the knocker, to allow
  checks on what UTC time Windows thinks it is.  (This helps fix
  any leftover 'incorrect secret' problems.)
  Added extra info on UTC problems to Windows docs 'knock.htm' & 'knock.txt'.

v0.6.1 July 16, 2004  JBW
  Added explicit check during configuration for the existence of the
  utility program 'lsof'.
  (The doorman needs lsof to know when to remove the firewall rule that
  allowed a connection after that connection is broken.  If 'lsof' is
  missing, old 'ALLOW' rules will never be removed.)

v0.6.2 July 16, 2004  JBW
  Corrected doormand installation 'chmod' commands in Makefile.am
  'knock' is unchanged from v0.6.1, for both *nix & winows

v0.7   July 22, 2004  JBW
  Added firewall scripts for FreeBSD, OpenBSD, & netBSD
  Changed error-reporting in all firewall scripts.

v0.8   July 29, 2004  JBW
  Fixed several bugs found by Leonid Shalupov.
  Added pidfile (suggested by Leonid)
  Changed default listening port to 1001
  Changed authentication method; time sync between client & server is
  no longer necessary. (Also: replay attacks are now more difficult)

v0.8.1  Aug.13, 2005  JBW
  Added support for linux cooked socket header len;  thanks to Markus Hoffmann.
  Fixed guestlist hostname-parsing bug; also thanks to Markus.
  Changed method of remembering old knock hashes, without use of Berkeley DB.
  Kinda-fixed a bug handling pcapnext-returns-null condition. I hope.
  Included lexer.c ('flex' output from lexer.l) in distribution. Duh.
  Fixed doorman bug when creating new new hashfile; thanks to Robert Koropcak
  No changes made to knock.c;   however, it will report being V0.81