I think im getting lost here. I read some of the documentation on how to use different public IPs on a network. Well heres the issue. I have a private nat network and I want A single piece of CPE I have to be public. Is this possible? Here is my network layout

(Comcast Router)----Public IP----Eth01(MTRB750)Eth02--Private(10.20.20.1){DHCP Sever}-----(MTRB Bridge)~~~~~(wireless)~~~~~(MTRB Bridge)------(MTRB AP) ~~~~(Client CPE)<--- is it possible to have this device be public?

If so how?

The only thing I could figure out how to do is to make that client go out an IP but I need that device to be reachable publicly.

Thanks

Not truly possible unless you have routed public IP space from your provider, or own public IP space from your RR. Do you? You can also set up NAT on the router that does have a public IP.

Yes I have about 10 pub ips. As of right now 5 are usable. So I should check the router that Comcast gave me?

Are those IPs ROUTED to you, or do you just have them available on the subnet on your router's WAN interface? If they're routed, this is easy. If they are on the subnet facing Comcast you can - if you own the ENTIRE subnet that is facing Comcast - use the ugly hack that is proxy ARP, or destination NAT if the CPE just needs to be reachable but doesn't need the public IP actually assigned to an interface.

My apologies on such a late response, I was on vaca.
Yes I believe they are routed to us. They gave us a router as well... So how should I set this up?

Just because you have a router doesn't mean you have routed public IP space. Is the IP address you want to assign to the CPE in the same IP network as the WAN IP address of your router? If yes, you destination and source NAT as per the wiki manual. If no, you just add the IP directly to the CPE and make sure all routers in-between either are running a common routing protocol so they know how to get to that IP, or have static routes in place.

It's possible with VLAN, I did it with two VLAN-aware switches. Before that I used an EoIP tunnel to bridge through a wireless link so one node on the other end could get a public IP.

VLAN: http://wiki.mikrotik.com/wiki/VLAN

EoIP Tunnel: http://wiki.mikrotik.com/wiki/Manual:Interface/EoIP

Edit: Added a network diagram for illustration purposes.

Will I be able to EoIP over this connection or do I need a true MT link?

The idea is to give CPE that connects to the MT AP a public IP.

Any ideas?