View Full Version : No NAT

2009-08-04, 08:22
Hi gurus

I was wondering

I have a site where I want to use official IP-addresses on all computers.

I have one IP-range (24-bit), and have to define it on both WAN and LAN. Will that be a problem? Should I configure wan with one address, and LAN with another, or should it have the same address on inside and outside?

I haven't tried yet, 'cause the UTM-1 is on a location long from here and if it crashes I have a problem.

Any good ideas, people?

2009-08-05, 06:28
You will have to subnet your /24 if you want to use IP from the same /24 on the WAN and LAN side of the UTM-1.

The easiest way ( and what I would STRONGLY suggest ) would be to get a /30 to use on the WAN side.

1 for Network
1 for ISP Router
1 for UTM-1
1 for Broadcast

Then just use the /24 on the inside and do no NAT Rules at all.

If you want to use the same /24 on both sides then you will lose a lot of IP in the subnetting as would need to use a /30 from the /24 to provide the WAN side. After the /24 then next usable would be the /25 which would halve what is available to you to on the inside.