diff --git a/Samples/one-interface/zones b/Samples/one-interface/zones
index 321c416bc..5f23e5155 100644
--- a/Samples/one-interface/zones
+++ b/Samples/one-interface/zones
@@ -20,16 +20,16 @@
 #		Example:
 #
 #			#ZONE     TYPE     OPTIONS
-#			a	  plain
-#			b	  plain
-#			c:a,b     plain
+#			a	  ipv4
+#			b	  ipv4
+#			c:a,b     ipv4
 #
 #		Currently, Shorewall uses this information only to reorder the
 #		zone list so that parent zones appear after their subzones in
 #		the list. In the future, Shorewall may make more extensive use
 #		of that information.
 #
-#	TYPE	plain -	This is the standard Shorewall zone type and is the
+#	TYPE	ipv4 -	This is the standard Shorewall zone type and is the
 #			default if you leave this column empty or if you enter
 #			"-" in the column. Communication with some zone hosts
 #			may be encrypted. Encrypted hosts are designated using
@@ -90,5 +90,5 @@
 #ZONE	TYPE	OPTIONS			IN			OUT
 #					OPTIONS			OPTIONS\
 fw	firewall
-net	plain
+net	ipv4
 #LAST LINE - ADD YOUR ENTRIES ABOVE THIS ONE - DO NOT REMOVE
diff --git a/Samples/three-interfaces/zones b/Samples/three-interfaces/zones
index b66bddc2a..88f916725 100644
--- a/Samples/three-interfaces/zones
+++ b/Samples/three-interfaces/zones
@@ -20,16 +20,16 @@
 #		Example:
 #
 #			#ZONE     TYPE     OPTIONS
-#			a	  plain
-#			b	  plain
-#			c:a,b     plain
+#			a	  ipv4
+#			b	  ipv4
+#			c:a,b     ipv4
 #
 #		Currently, Shorewall uses this information only to reorder the
 #		zone list so that parent zones appear after their subzones in
 #		the list. In the future, Shorewall may make more extensive use
 #		of that information.
 #
-#	TYPE	plain -	This is the standard Shorewall zone type and is the
+#	TYPE	ipv4 -	This is the standard Shorewall zone type and is the
 #			default if you leave this column empty or if you enter
 #			"-" in the column. Communication with some zone hosts
 #			may be encrypted. Encrypted hosts are designated using
@@ -88,7 +88,7 @@
 #ZONE	TYPE	OPTIONS			IN			OUT
 #					OPTIONS			OPTIONS
 fw	firewall
-net	plain
-loc	plain
-dmz	plain
+net	ipv4
+loc	ipv4
+dmz	ipv4
 #LAST LINE - ADD YOUR ENTRIES ABOVE THIS ONE - DO NOT REMOVE
diff --git a/Samples/two-interfaces/zones b/Samples/two-interfaces/zones
index af7b5181b..7e3e8a14e 100644
--- a/Samples/two-interfaces/zones
+++ b/Samples/two-interfaces/zones
@@ -20,16 +20,16 @@
 #		Example:
 #
 #			#ZONE     TYPE     OPTIONS
-#			a	  plain
-#			b	  plain
-#			c:a,b     plain
+#			a	  ipv4
+#			b	  ipv4
+#			c:a,b     ipv4
 #
 #		Currently, Shorewall uses this information only to reorder the
 #		zone list so that parent zones appear after their subzones in
 #		the list. In the future, Shorewall may make more extensive use
 #		of that information.
 #
-#	TYPE	plain -	This is the standard Shorewall zone type and is the
+#	TYPE	ipv4 -	This is the standard Shorewall zone type and is the
 #			default if you leave this column empty or if you enter
 #			"-" in the column. Communication with some zone hosts
 #			may be encrypted. Encrypted hosts are designated using
@@ -88,7 +88,7 @@
 #ZONE	TYPE	OPTIONS			IN			OUT
 #					OPTIONS			OPTIONS
 fw	firewall
-net	plain
-loc	plain
+net	ipv4
+loc	ipv4
 
 #LAST LINE - ADD YOUR ENTRIES ABOVE THIS ONE - DO NOT REMOVE
diff --git a/Shorewall/changelog.txt b/Shorewall/changelog.txt
index 74044987f..2ee007583 100755
--- a/Shorewall/changelog.txt
+++ b/Shorewall/changelog.txt
@@ -6,6 +6,8 @@ Changes in 2.5.7
 
 3) Add capabilities report to "shorewall dump".
 
+4) Rename 'plain' to 'ipv4'
+
 Changes in 2.5.6
 
 1) Finish install/fallback cleanup.
diff --git a/Shorewall/firewall b/Shorewall/firewall
index c05017dfe..c847be05c 100755
--- a/Shorewall/firewall
+++ b/Shorewall/firewall
@@ -553,8 +553,8 @@ determine_zones()
         esac
 
 	if [ -n "$new_zone_file" ]; then
-	    case ${type:=plain} in
-		plain|-)
+	    case ${type:=ipv4} in
+		ipv4|plain|-)
 		    list_search $zone $ZONES $FW && startup_error "Zone $zone is defined more than once"
 		    merge_zone
 		    ;;
diff --git a/Shorewall/releasenotes.txt b/Shorewall/releasenotes.txt
index 11b583789..e05c93696 100755
--- a/Shorewall/releasenotes.txt
+++ b/Shorewall/releasenotes.txt
@@ -61,9 +61,9 @@ Migration Considerations:
 			Example:
 
 				#ZONE     TYPE     OPTIONS
-				a	  plain
-				b	  plain
-				c:a,b     plain
+				a	  ipv4
+				b	  ipv4
+				c:a,b     ipv4
 
 		        Currently, Shorewall uses this information only
 		        to reorder the zone list so that parent zones
@@ -71,7 +71,7 @@ Migration Considerations:
 			future, Shorewall may make more extensive use
 		        of that information.
 
-	TYPE	plain -	This is the standard Shorewall zone type and is
+	TYPE	ipv4 -	This is the standard Shorewall zone type and is
 			the default if the column is left empty or if
 			it is entered as "-".  Communication with some
 			zone hosts may be encrypted. Encrypted hosts
diff --git a/Shorewall/zones b/Shorewall/zones
index 09bcaf7fa..c02c74f7a 100644
--- a/Shorewall/zones
+++ b/Shorewall/zones
@@ -20,16 +20,16 @@
 #		Example:
 #
 #			#ZONE     TYPE     OPTIONS
-#			a	  plain
-#			b	  plain
-#			c:a,b     plain
+#			a	  ipv4
+#			b	  ipv4
+#			c:a,b     ipv4
 #
 #		Currently, Shorewall uses this information only to reorder the
 #		zone list so that parent zones appear after their subzones in
 #		the list. In the future, Shorewall may make more extensive use
 #		of that information.
 #
-#	TYPE	plain -	This is the standard Shorewall zone type and is the
+#	TYPE	ipv4 -	This is the standard Shorewall zone type and is the
 #			default if you leave this column empty or if you enter
 #			"-" in the column. Communication with some zone hosts
 #			may be encrypted. Encrypted hosts are designated using