We are taking 512kbps internet bandwidth from one ISP to our office A and they are giving /29 public IP ( or if we want they will give more on the same segment ).
The point is we are having one more office E where we will going to setup mail server and webserver . from office A to reach office E 3 hops are there mean in middle 3 routers are there it has to cross 3 locations ( management don't want to take one more pipe from location A to E ). if i assign the public ip address to our mail server and web server which will be going to locate at Location E how i can propagate this public ip to internet , i thought of creating tunnel between office A and office E but how i can propagate these public IP's please help me.
Can you use NAT on your internet router in office A?
If you can, you could just set up a static mapping between a dedicated internet address and the internal address of your mailserver. Your internet-facing router would translate the address to the one you defined on your internal network, and you internal network should then be able to route it to office E.
Alternatively, can't you put your mailserver and webserver at office A? It would avoid unnecessary traffic going to and fro across your routers