diff --git a/ixwebsocket/CMakeLists.txt b/ixwebsocket/CMakeLists.txt
index 74b38a5..dbdab8b 100644
--- a/ixwebsocket/CMakeLists.txt
+++ b/ixwebsocket/CMakeLists.txt
@@ -64,6 +64,8 @@ elseif(UNIX)
     target_compile_definitions(ixwebsocket PRIVATE
         IXWEBSOCKET_USE_TLS
         IXWEBSOCKET_USE_OPEN_SSL
+        SSL_CERT_DIR=/etc/ssl/certs
+        SSL_CERT_FILE=/etc/ssl/cert.pem
     )
     target_compile_options(ixwebsocket PRIVATE
         -nodefaultlibs