diff --git a/tests/compat.sh b/tests/compat.sh
index 06243bde4..dc03ebdb3 100755
--- a/tests/compat.sh
+++ b/tests/compat.sh
@@ -965,7 +965,7 @@ MAIN_PID="$$"
 
 # Pick a "unique" port in the range 10000-19999.
 PORT="0000$$"
-PORT="1$(echo $PORT | tail -c 4)"
+PORT="1$(echo $PORT | tail -c 5)"
 
 # Also pick a unique name for intermediate files
 SRV_OUT="srv_out.$$"
diff --git a/tests/ssl-opt.sh b/tests/ssl-opt.sh
index ddb7a0ac0..f43f1eb54 100755
--- a/tests/ssl-opt.sh
+++ b/tests/ssl-opt.sh
@@ -316,7 +316,7 @@ fi
 
 # Pick a "unique" port in the range 10000-19999.
 PORT="0000$$"
-PORT="1$(echo $PORT | tail -c 4)"
+PORT="1$(echo $PORT | tail -c 5)"
 
 # fix commands to use this port
 P_SRV="$P_SRV server_port=$PORT"