diff --git a/tests/compat.sh b/tests/compat.sh
index 724311cf7..1eea23cbd 100755
--- a/tests/compat.sh
+++ b/tests/compat.sh
@@ -645,14 +645,14 @@ setup_arguments()
             exit 1;
     esac
 
-    P_SERVER_ARGS="server_addr=0.0.0.0 force_version=$MODE"
-    O_SERVER_ARGS="-www -cipher NULL,ALL -$MODE"
-    G_SERVER_ARGS="-p 4433 --http"
+    P_SERVER_ARGS="server_port=$PORT server_addr=0.0.0.0 force_version=$MODE"
+    O_SERVER_ARGS="-accept $PORT -www -cipher NULL,ALL -$MODE"
+    G_SERVER_ARGS="-p $PORT --http"
     G_SERVER_PRIO="EXPORT:+NULL:+MD5:+PSK:+DHE-PSK:+ECDHE-PSK:+RSA-PSK:-VERS-TLS-ALL:$G_PRIO_MODE"
 
-    P_CLIENT_ARGS="force_version=$MODE"
-    O_CLIENT_ARGS="-$MODE"
-    G_CLIENT_ARGS="-p 4433 --debug 3"
+    P_CLIENT_ARGS="server_port=$PORT force_version=$MODE"
+    O_CLIENT_ARGS="-connect localhost:$PORT -$MODE"
+    G_CLIENT_ARGS="-p $PORT --debug 3"
     G_CLIENT_PRIO="NONE:$G_PRIO_MODE:+COMP-NULL:+CURVE-ALL:+SIGN-ALL"
 
     if [ "X$VERIFY" = "XYES" ];
@@ -952,7 +952,10 @@ for PEER in $PEERS; do
     esac
 done
 
-killall -q gnutls-serv openssl ssl_server ssl_server2
+# Pick a "unique" port in the range 10000-19999.
+PORT="0000$$"
+PORT="1$(echo $PORT | tail -c 4)"
+
 trap cleanup INT TERM HUP
 
 for VERIFY in $VERIFIES; do
diff --git a/tests/ssl-opt.sh b/tests/ssl-opt.sh
index f4fbc019b..4df999eb6 100755
--- a/tests/ssl-opt.sh
+++ b/tests/ssl-opt.sh
@@ -153,7 +153,7 @@ run_test() {
 
     # psk is useful when server only has bad certs
     if is_polar "$SRV_CMD"; then
-        "$P_CLI" request_page=SERVERQUIT tickets=0 auth_mode=none psk=abc123 \
+        $P_CLI request_page=SERVERQUIT tickets=0 auth_mode=none psk=abc123 \
             crt_file=data_files/cli2.crt key_file=data_files/cli2.key \
             >/dev/null
     else
@@ -276,7 +276,16 @@ if which $OPENSSL_CMD >/dev/null 2>&1; then :; else
     exit 1
 fi
 
-killall -q openssl ssl_server ssl_server2
+# Pick a "unique" port in the range 10000-19999.
+PORT="0000$$"
+PORT="1$(echo $PORT | tail -c 4)"
+
+# fix commands to use this port
+P_SRV="$P_SRV server_port=$PORT"
+P_CLI="$P_CLI server_port=$PORT"
+O_SRV="$O_SRV -accept $PORT"
+O_CLI="$O_CLI -connect localhost:$PORT"
+
 trap cleanup INT TERM HUP
 
 # Test for SSLv2 ClientHello