multiple VLAN's public IP's and NATd's : HowTo ?

[Kristian Rask]

Hi all

How would one go about running several instances of natd with unique public IP's for several VLAN's terminated on the same interface ?

The idea being that multiple seperate RFC-1918 networks are
terminated as VLANS in the FreeBSD machine and that
each VLAN goes through a seperate NAT'd instance in order to
NAT on a particular public IP.

1. House full of businesses.. (here shown w. 5/8)
2. Each buisiness has it's own LAN
3. Each LAN goes into a switch where the port is configured as a particular LAN
4. The switch is connected to a FreeBSD machine w. a set of
VLAN's matching those in the seperate businesses
5. There should be 1 instance of NATd running for each VLAN
6. Each NATd uses seperate public IP's
7. WAN Staticly configured using a /30
8. /29 net for 5/8 seperate NATd's (a.b.c.0/29) routed to the wan.
9. possibly "ifconfig SomePhysIf0 a.b.c.1/29"

I think for 5 IP's it would be something like:

for i in  2 3 4 5 6; do
  natd -port 100${i} \
  -f /etc/natd_${i}.conf \
  -n <phys-if or vlan ?> \
  -a a.b.c.${i}
done

for i in 2 3 4 5 6; do
  ipfw add divert 100${i} all .... 
   (from VLAN-if | VLAN-CIDR | ... ?) 
   to any ...(in via VLAN-if | out via WAN-if | .... ?)
done

i *assume* i need to configure the /29 somewhere ..
i *suspect* that i can do something "weird" and actually
use all 8 IP's  ... perhaps configure the 8 IP's as aliases on lo ?

we will have more than a few addresses in order to be able to deliver
routeable addresses if anyone so requests..
like.. a /26 of wich we use a /28 for permanent IP's and can deliver
6 /29 for the few who actually needs a routable network.

anyone has any experiences or hints / pointers ?



TIA and regards

Kristian aka The eternal newbie