Simple Routing Question - should be

RouterOS Beginner Basics
1

I have a class C from our provider for us to use. We also have a /30 for our wan port.
Internally I have 2 networks a 172.16 network and an 172.18 network and a DMZ. The DMZ is run on Public IP’s so I know

My class C I have broken down like so:
x.x.x.128/25 points to 172.16 gateway
x.x.x.32/25 points to DMZ Port

I have a couple left I am reserving until this is resolved to be used if needed.

I do not want masquarading on the DMZ or the 172.16 public ips, But I do on the 172.16.x.x and 172.18.x.x IPs I could use src-nat or masquerade but what do I set for the to-address. It wouldn’t be the providers /30 do I have to assign a public ip to the 172.16 and 172.18 interface, to the WAN or what…

2

I’m not sure, how you planned to setup DMZ on the network.

As you have only one address from /30 network available, you can forward ports from one available public IP Address.
However you need more public (routable) IP addresses to assign them to the devices from DMZ.

Currently you have only one address public IP address from /30 to set it to-addresses.