diff --git a/client/site_tests/platform_Firewall/platform_Firewall.py b/client/site_tests/platform_Firewall/platform_Firewall.py
index ff60d05..181ee9c 100644
--- a/client/site_tests/platform_Firewall/platform_Firewall.py
+++ b/client/site_tests/platform_Firewall/platform_Firewall.py
@@ -17,8 +17,12 @@
     version = 1
 
     _PORT = 1234
+    _IFACE = "eth0"
+
     _TCP_RULE = "-A INPUT -p tcp -m tcp --dport %d -j ACCEPT" % _PORT
     _UDP_RULE = "-A INPUT -p udp -m udp --dport %d -j ACCEPT" % _PORT
+    _IFACE_RULE = "-A INPUT -i %s -p tcp -m tcp --dport %d -j ACCEPT" % (_IFACE,
+                                                                         _PORT)
 
     _POLL_INTERVAL = 5
 
@@ -39,22 +43,34 @@
 
         self.tcp_r, self.tcp_w = os.pipe()
         self.udp_r, self.udp_w = os.pipe()
+        self.iface_r, self.iface_w = os.pipe()
 
         try:
             tcp_lifeline = dbus.types.UnixFd(self.tcp_r)
-            ret = pb.RequestTcpPortAccess(dbus.UInt16(self._PORT), tcp_lifeline)
+            ret = pb.RequestTcpPortAccess(dbus.UInt16(self._PORT), "",
+                                          tcp_lifeline)
             # |ret| is a dbus.Boolean, but compares as int.
             if ret == 0:
                 raise error.TestFail(
                         "RequestTcpPortAccess returned false.")
 
             udp_lifeline = dbus.types.UnixFd(self.udp_r)
-            ret = pb.RequestUdpPortAccess(dbus.UInt16(self._PORT), udp_lifeline)
+            ret = pb.RequestUdpPortAccess(dbus.UInt16(self._PORT), "",
+                                          udp_lifeline)
             # |ret| is a dbus.Boolean, but compares as int.
             if (ret == 0):
                 raise error.TestFail(
                         "RequestUdpPortAccess returned false.")
 
+            iface_lifeline = dbus.types.UnixFd(self.iface_r)
+            ret = pb.RequestTcpPortAccess(dbus.UInt16(self._PORT),
+                                          dbus.String(self._IFACE),
+                                          iface_lifeline)
+            # |ret| is a dbus.Boolean, but compares as int.
+            if (ret == 0):
+                raise error.TestFail(
+                        "RequestTcpPortAccess(port, interface) returned false.")
+
             rules = self._iptables_rules()
             if self._TCP_RULE not in rules:
                 raise error.TestFail(
@@ -62,19 +78,25 @@
             if self._UDP_RULE not in rules:
                 raise error.TestFail(
                         "RequestUdpPortAccess did not add iptables rule.")
+            if self._IFACE_RULE not in rules:
+                raise error.TestFail(
+                        "RequestTcpPortAccess(port, interface)"
+                        " did not add iptables rule.")
 
             # permission_broker should plug the firewall hole
             # when the requesting process exits.
             # Simulate the process exiting by closing both write ends.
             os.close(self.tcp_w)
             os.close(self.udp_w)
+            os.close(self.iface_w)
 
             # permission_broker checks every |_POLL_INTERVAL| seconds
             # for processes that have exited.
             # This is ugly, but it's either this or polling /var/log/messages.
             time.sleep(self._POLL_INTERVAL + 1)
             rules = self._iptables_rules()
-            if self._TCP_RULE in rules or self._UDP_RULE in rules:
+            if (self._TCP_RULE in rules or self._UDP_RULE in rules
+                or self._IFACE_RULE in rules):
                 raise error.TestFail(
                         "permission_broker did not remove iptables rule.")
 
@@ -87,6 +109,7 @@
         try:
             os.close(self.tcp_w)
             os.close(self.udp_w)
+            os.close(self.iface_w)
         except OSError:
             pass
 
@@ -98,3 +121,6 @@
         utils.system(cmd, ignore_status=True)
         cmd = self._IPTABLES_DEL_CMD % ("udp", "udp", self._PORT)
         utils.system(cmd, ignore_status=True)
+        cmd = self._IPTABLES_DEL_CMD % ("tcp", "tcp", self._PORT)
+        cmd += " -i %s" % self._IFACE
+        utils.system(cmd, ignore_status=True)