[BRIDGING]: Update Kconfig files for bridging firewall.

net/Kconfig

@@ -191,9 +191,11 @@ config BRIDGE
 	  information.
 
 	  If you enable iptables support along with the bridge support then you
-	  turn your bridge into a bridging firewall.
+	  turn your bridge into a bridging IP firewall.
 	  iptables will then see the IP packets being bridged, so you need to
 	  take this into account when setting up your firewall rules.
+	  Enabling arptables support when bridging will let arptables see
+	  bridged ARP traffic in the arptables FORWARD chain.
 
 	  If you want to compile this code as a module ( = code which can be
 	  inserted in and removed from the running kernel whenever you want),
@@ -243,6 +245,12 @@ menuconfig NETFILTER
 	  box can transparently forward the traffic to a local server,
 	  typically a caching proxy server.
 
+	  Yet another use of Netfilter is building a bridging firewall. Using
+	  a bridge with Network packet filtering enabled makes iptables "see"
+	  the bridged traffic. For filtering on the lower network and Ethernet
+	  protocols over the bridge, use ebtables (under bridge netfilter
+	  configuration).
+
 	  Various modules exist for netfilter which replace the previous
 	  masquerading (ipmasqadm), packet filtering (ipchains), transparent
 	  proxying, and portforwarding mechanisms. Please see

net/bridge/netfilter/Kconfig

 #
 # Bridge netfilter configuration
 #
+
+menu "Bridge: Netfilter Configuration"
+	depends on BRIDGE && NETFILTER
+
 config BRIDGE_NF_EBTABLES
-	tristate "Bridge: ebtables"
-	depends on NETFILTER && BRIDGE
+	tristate "Ethernet Bridge tables (ebtables) support"
+	help
+	  ebtables is a general, extensible frame/packet identification
+	  framework. Say 'Y' or 'M' here if you want to do Ethernet
+	  filtering/NAT/brouting on the Ethernet bridge.
 #
 # tables
 #
@@ -172,3 +179,5 @@ config BRIDGE_EBT_LOG
 
 	  If you want to compile it as a module, say M here and read
 	  <file:Documentation/modules.txt>.  If unsure, say `N'.
+
+endmenu