$ OPENSSL_PREFIX=/home/cavac/bin/openssl LD_LIBRARY_PATH=/home/cavac/bin/openssl/lib:$LD_LIBRARY_PATH perl Makefile.PL *** Found OpenSSL-1.1.1a installed in /home/cavac/bin/openssl *** That's newer than what this module was tested with You should consider checking if there is a newer release of this module available. Everything will probably work OK, though. *** Be sure to use the same compiler and options to compile your OpenSSL, perl, and Net::SSLeay. Mixing and matching compilers is not supported. Do you want to run external tests?