I am trying to configure stunnel on a bridge server which needs to use ssl to talk to 3 others servers. below is my conf file:  ; ***************************************** Example SSL server mode services [ xyz ] accept=10.10.10.74:9908 connect= 127.0.0.10:1040 transparent = source[ hp ] accept=10.10.10.218:9904 connect=127.0.0.10:1041 transparent = source[ sql] accept=10.10.10.214:59053 connect=127.0.0.10:1042 transparent = source when I run the stunnel GUI start I get following message: [ ] No limit detected for the number of clients [.] stunnel 5.10 on x86-pc-msvc-1500 platform [.] Compiled/running with OpenSSL 1.0.1l 15 Jan 2015 [.] Threading:WIN32 Sockets:SELECT,IPv6 TLS:ENGINE,FIPS,OCSP,PSK,SNI [ ] errno: (*_errno()) [.] Reading configuration from file stunnel.conf [ ] GUI message loop initialized [.] UTF-8 byte order mark detected [ ] Enabling support for engine "capi" [ ] Initializing engine #1 (capi) [ ] Engine #1 (capi) initialized [.] FIPS mode disabled [ ] Compression disabled [ ] Snagged 64 random bytes from C:/.rnd [ ] Wrote 1024 new random bytes to C:/.rnd [ ] PRNG seeded successfully [!] Line 62: "transparent = source": Specified option name is not valid here[!] Server is down what am I missing here?  thanks! nazja2015