Hi.
I have a problem. I have assigned by the ISP ip 5. I have a Mikrotik RB333 on it first assigned to eth1 ip address and the DHCP server on it other than a set of ISP. I need to set an IP DHCP published (DNAT and SNAT) in 2-5 ip address. I tried everything possible and not to me 
It explains the bad, the picture will be better
I am not exactly sure what your asking. You are getting assigned a ip address from your isp, and you have snats and dnats set up with the ip? What I think your asking is how do you set up something so it automatically changes those ips in the dstnats and srcnats? Is that what your asking?
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i think he’s encountering a similar issue to what i am having:
his ISP assigned (4) IP addresses and he has (4) subnets in his LAN. he wants to assign one IP to each subnet, but only has one interface connected from the MT to the ISP modem or router. he can’t figure out how to get the NAT to do what he wants because the single MT interface has one of the IPs assigned to it and the NAT isn’t working to route the other public IPs to the correct subnets in his LAN.
maybe he can verify whether that’s an accurate description or not.
enable proxy-arp on the interface facing to your provider.
add four masquerading rules. one for each public IP and lan-subnet
If you want to use all 4 of the IPs for NATing then add them all to the WAN interface.
Nick.
can you be more specific about how? in the IP addresses window, for the WAN interface i have the address as “x.x.x.146/29”, which i thought would do just that (our network starts at .144 with 8 IPs available, including network & broadcast - .145 is the WAN router’s address and .146 is what i use on the MT for gateway). in the interfaces window it only shows .146 as associated with that interface, though.
thanks for the suggestion. sorry if this is a thread hijack. hopefully the OP will be getting useful info from this as well (if he’s still looking for answers here).
EDIT:
nevermind, i just figured it out! really easy once you realize you can do it, lol. i am now able to ping my secondary address, which i was not able to do before, so i think i have finally solved my problem here.
i posted a screenshot of my config in this thread: http://forum.mikrotik.com/t/how-to-map-my-public-ip-to-be-equal-with-one-local-ip/53813/1 to show what i did to implement Nick’s solution.