Jeff,   I believe the last line in the log might point you in the right direction.   Looks like FIPS mode is not supported on Windows 2000 You could disable FIPS mode on your config file. See the FIPS options on the manual. Of course this is assuming that you don't need to run FIPS for any compliance reasons.  Cheers ----------------- Leandro Avila ________________________________ From: Jeff Salisbury <[email protected]> To: [email protected] Sent: Monday, April 2, 2012 5:09 PM Subject: [stunnel-users] Configure Stunnel 4.53 to Run on a Windows 2000 Machine? Greetings, we recently updated Stunnel to version 4.53 and we've discovered that Stunnel no longer runs on our Windows 2000 workstation.  Here is the message in the Stunnel log: No limit detected for the number of clients stunnel 4.53 on x86-pc-mingw32-gnu platform Compiled/running with OpenSSL 0.9.8s-fips 4 Jan 2012 Threading:WIN32 SSL:+ENGINE+OCSP+FIPS Auth:none Sockets:SELECT+IPv4 Reading configuration from file C:\bin\Stunnel\stunnel.conf FIPS_mode_set: 2D06C071: error:2D06C071:FIPS routines:FIPS_mode_set:unsupported platform Server is down Please help!  Is there a configuration change or addition we can make in our Stunnel.conf file that will allow us to run v4.53 on our Windows 2000 machine? Regards, Jeff _______________________________________________ stunnel-users mailing list [email protected] http://stunnel.mirt.net/mailman/listinfo/stunnel-users