Prefer ipv6.

ansible/roles/jail/files/jail_netgraph_bridge.bash

@@ -23,11 +23,15 @@ function start_jail {
     jail_interface_name=$(sanitize_interface_name "$2")
     ip_range="$3"
 
+    local mac_address
+    mac_address=$(calculate_mac_address "$jail_interface_name")
+
     assert_bridge "$host_interface_name" "$bridge_name" "$ip_range"
 
     bridge_link_name=$(detect_available_link "${bridge_name}")
     ngctl -d -f - <<EOF
 mkpeer ${bridge_name}: eiface $bridge_link_name ether
+msg ${bridge_name}:$bridge_link_name set $mac_address
 name ${bridge_name}:$bridge_link_name $jail_interface_name
 EOF
     ifconfig $(ngctl msg "${jail_interface_name}:" getifname | grep Args | cut -d '"' -f 2) name "${jail_interface_name}" up
@@ -121,4 +125,11 @@ function sanitize_interface_name {
     echo "${1:0:15}"
 }
 
+function calculate_mac_address {
+    local name="$1"
+    local source
+    source=$(md5 -r -s "$name" | awk '{print $1}')
+    echo "06:${source:0:2}:${source:2:2}:${source:4:2}:${source:6:2}:${source:8:2}"
+}
+
 main "${@}"