Firewall rules don't work on 464xlat because they were created under an assumption that there's only one address for the server and it's ipv4, which doesn't go so well when we're on an ipv6-only network. Bug: 33159037 Test: runtest -x net/java/com/android/server/connectivity/VpnTest.java Change-Id: Id331526367fe13838874961da194b07bd50d4c97