Question: I have a Virtual Box machine with 2 net adapters, first is an "internal net" and the second a "bridge adapter". How could I config both for have an static ip for the internal network and a dynamic ip for bridge?

I tried modifying `/etc/network/interfaces`:

```
#localhost
auto lo
iface lo inet loopback

iface eth0 inet static
address 192.168.1.20
netmask 255.255.255.0
network 192.168.1.0
broadcast 192.168.1.255
gateway 192.168.1.1

# dns-* options are implemented by the resolvconf package, if installed
dns-nameservers 8.8.8.8
dns-search lcl

iface eth1 inet dhcp

```

But when I restart the machine I get:

```
lo        Link encap:Bucle local  
          Direc. inet:127.0.0.1  Másc:255.0.0.0
          Dirección inet6: ::1/128 Alcance:Anfitrión
          ACTIVO BUCLE FUNCIONANDO  MTU:16436  Métrica:1
          Paquetes RX:124 errores:0 perdidos:0 overruns:0 frame:0
          Paquetes TX:124 errores:0 perdidos:0 overruns:0 carrier:0
          colisiones:0 long.colaTX:0 
          Bytes RX:10400 (10.4 KB)  TX bytes:10400 (10.4 KB)

```

Answer: 
I found that `nsupdate` can be used as a workaround to create a PTR record from the Linux side:

```
banjer@myhost~> nsupdate
> update add 210.31.20.192.in-addr.arpa 3600 ptr myhost.example.com.
> send

```

That same command as a one-liner:

```
echo -e "update add 210.31.20.192.in-addr.arpa 3600 ptr myhost.example.com.\nsend" | nsupdate

```

Where 210.31.20.192 is your IP in reverse order. 

I'm open to a better answer for getting net ads to add the PTR record properly though.
First you need to create a primary reverse lookup zone for that network then windows server can automatically create the necessary PTR records when you add a A(AAA) host record in your primary forward lookup zones.