diff --git a/rootfs/src/entry.sh b/rootfs/src/entry.sh
index 91ed6be3..fbdbfd66 100644
--- a/rootfs/src/entry.sh
+++ b/rootfs/src/entry.sh
@@ -1,5 +1,12 @@
 #!/bin/bash
 
+test -z "$VNC_OFFSET" && export VNC_OFFSET=10
+# if PORT_XXX not set, quick set mode
+if [ $VNC_OFFSET -gt 10 ] && [ "$VNC_OFFSET" -lt 66 ]; then
+    test -z "$PORT_SSH" && export PORT_SSH=$(($PORT_SSH*1000+22))
+    test -z "$PORT_RDP" && export PORT_RDP=$(($PORT_SSH*1000+89))
+    test -z "$PORT_VNC" && export PORT_VNC=$(($PORT_SSH*1000+81))
+fi
 test -z "$PORT_SSH" && export PORT_SSH=10022
 test -z "$PORT_RDP" && export PORT_RDP=10089
 test -z "$PORT_VNC" && export PORT_VNC=10081
@@ -7,7 +14,6 @@ test -z "$PORT_VNC" && export PORT_VNC=10081
 test -z "$SSH_PASS" && export SSH_PASS=headless
 test -z "$VNC_PASS" && export VNC_PASS=headless
 test -z "$VNC_PASS_RO" && export VNC_PASS_RO=View123
-test -z "$VNC_OFFSET" && export VNC_OFFSET=10
 
 # TODO: check port: ssh, rdp, vnc
 # sudo: unable to resolve host x11-ubuntu: Name or service not known