diff --git a/tests/ssl-opt.sh b/tests/ssl-opt.sh
index 5cf4ff6..4595b89 100755
--- a/tests/ssl-opt.sh
+++ b/tests/ssl-opt.sh
@@ -17,7 +17,7 @@
 : ${GNUTLS_CLI:=gnutls-cli}
 : ${GNUTLS_SERV:=gnutls-serv}
 
-O_SRV="$OPENSSL_CMD s_server -www -cert data_files/server5.crt -key data_files/server5.key"
+O_SRV="$OPENSSL_CMD s_server -www -cert data_files/server5.crt -key data_files/server5.key -dhparam data_files/dhparams.pem"
 O_CLI="echo 'GET / HTTP/1.0' | $OPENSSL_CMD s_client"
 G_SRV="$GNUTLS_SERV --x509certfile data_files/server5.crt --x509keyfile data_files/server5.key"
 G_CLI="echo 'GET / HTTP/1.0' | $GNUTLS_CLI --x509cafile data_files/test-ca_cat12.crt"