diff --git a/tunmgr/tunmgr.py b/tunmgr/tunmgr.py
index 017f31b00b187746a71fe0c527765bc17b2e0108..44795ddd1ef7a16e70281ca8ddb9e388a73b6061 100755
--- a/tunmgr/tunmgr.py
+++ b/tunmgr/tunmgr.py
@@ -9,9 +9,10 @@ import traceback
 
 tun = TunTapDevice()
 
-
-tun.addr = '10.8.0.1'
-tun.dstaddr = '10.8.0.2'
+addrs = ("10.8.0.1", "10.8.0.2")
+if len(sys.argv)>2:
+    addrs = tuple(reversed(addrs))
+tun.addr, tun.dstaddr = addrs
 tun.netmask = '255.255.255.0'
 tun.mtu = 100