iptables, virtualbox and port forwarding

[berenger.morel@neutralite.org]

Hello list.

I am trying to build a virtual network exposing servers accessible from 
the LAN.
I have done a lot of searches on the web and it worked last week, but 
since then, I have restarted my computer and had the nice surprise to 
learn that the iptables command does not save it's configuration.
I tried to retrieve my configuration, but am failing ( I tried to 
understand what I did with the history command, but sadly I am always 
working with tons of terminals and so, I suspect that it is not the 
correct history... ), and same to find anew the articles which actually 
make things working.

I had some network knowledge in the past, but never really practiced 
it, so I have lost almost everything. I already have used some 
firewalls, but those were some Windows ones ( I was not a linux user at 
that time ) and so I have never played  with iptables.

So I ask for 2 things:
_ help on this particular problem
_ if someone knows about resources to learn and understand how exactly 
iptables work, this would help me a lot in the future

For my particular problem.

I have an eth0 interface, the real one, on ip 172.20.14.0/24.
I made a vlan in my /etc/network/interfaces, like this:
##############################
auto eth0.1
iface eth0.1 inet static
	address 10.10.10.1
	netmask 255.255.255.0
	vlan-raw-device eth0
##############################

On that network, I have some VMs with static IPs, and the one on which 
I try to make the configuration for testing and learning purpose have an 
apache2 server running and up ( I can query on it from my physical 
computer ). It is using 2 network interfaces, a NAT one and a bridge 
one, but for others I would like to remove the NAT one, since I need 
them to simulate the production servers ( which are VMs too, but my 
company does not control the system on which they are running. Otherwise 
it would have be far easier: I would have read how it does to understand 
things ) which only have one interface ( eth0 ).

Both LANs ( the physical one and the virtual one ) works perfectly, but 
now I would like to allow 2 things:
_ VMs to access the physical LAN, so that they could access the apt 
proxy I have installed there for installing softwares and updates
_ physical computers accessing VMs through some ports of my computer. 
For example, redirecting "172.20.14.XX:80" to "10.10.10.30:80". I will 
do that port forwarding for ssh ( port 22 ), http ( port 80 ) and 
postgresql ( port 5432 ) connections in a first time.

Thanks