firewall: allow DHCPv6 traffic to/from fc00::/6 instead of fe80::/10

There is no RFC requirement that DHCPv6 servers must reply with a link local
address and some ISP servers in the wild appear to using addresses in the ULA
range to send DHCPv6 offers.

Signed-off-by: Jo-Philipp Wich <jow@openwrt.org>

SVN-Revision: 47048

package/network/config/firewall/files/firewall.config

@@ -59,8 +59,8 @@ config rule
 	option name		Allow-DHCPv6
 	option src		wan
 	option proto		udp
-	option src_ip		fe80::/10
-	option dest_ip		fe80::/10
+	option src_ip		fc00::/6
+	option dest_ip		fc00::/6
 	option dest_port	546
 	option family		ipv6
 	option target		ACCEPT