Hi all.
My main router, x86 Mikrotik 3.17, serves a large number of networks, each with its own private IP range.
Each network has many different users, and these users can change IP, (within their own private network), and add or remove users as needed.
Right now, all the networks masquerade out thru a single public IP. This is no longer acceptable, for many reasons, I need to masquerade each network to its own public IP.
I do not need or wish to map each user to their own public IP, just each network.
Does any one know how to do this?
Theoryman
Are your public IPs on separate interfaces?
Static IP or dhcp assigned?
One IP per interface, or more than one?
There is also an entry in the wiki under the routing section on load balancing that you might find useful.
You can do what you want with the SRCNAT & DSTNAT rules in the IP>FIREWALL>NAT menus.
SRCNAT rules are used to make traffic FROM a subnet appear to come FROM a public IP.
DSTNAT rules are used to make traffic TO a public IP be sent to a specific Private IP. AKA Port forwarding. Or IP Alias.
So Private suibnet 1 is srcnatted to public IP 1 and private subnet 2 is src natted to publci ip 2 etc…
But watch out if you are using web proxy on the same router… 
The Wiki article mentioned before is well worth looking at. wiki.mikrotik.com…
Rgds
Alex
As Alex mentioned, I set up a router to do this once:
/ip firewall nat
add action=src-nat chain=srcnat comment=“CCU1 Nat” disabled=no src-address=172.16.4.0/22
to-addresses=xxx.xxx.xxx.xx1
add action=src-nat chain=srcnat comment=“CCU2 Nat” disabled=no src-address=172.16.8.0/22
to-addresses=xxx.xxx.xxx.xx2
where xxx.xxx.xxx.1 and 2 are the public addresses that I wanted to nat to.
Tom