I just confirmed that RLE compression is not truly implemented in OpenSSL.  It would be helpful to remove it from the stunnel docs so people don’t think it’s an option to compress data.  ZLIB is it. 

And yes I spent a good bit of time last year with Wireshark to determine RLE vs ZLIB compression ratios in stunnel.  Shockingly ZLIB was always better…

One other note that may be important for some people is that 0.9.7 openssl is not compatible with 0.9.8 with respect to zlib compression.

Joe A. Kemp

CapWIN Senior Systems Architect

(O) 301-614-3727 (C) 301-502-1281