[CentOS] Forward all traffic from public IP A to public IP B?

[John R Pierce]

Morten Sundstrøm wrote:
> No nothing will go back from B through A, traffic from B vil go 
> directly to the quering host. Sort of like manipulate the header of 
> every packet changing destination IP to New destination IP and let the 
> new destination host answer the query. Maybe im way of here :) and if 
> I am then somone just say it and i will forget the whole ting.


yeah, that flat won't work.

    client C sends packet with source address:C, destination address A, 
port P
    A forwards packet to B with src: C, dest: B, port P
    B replies to C with src: B, dest C

C goes 'wtf is this packet?  I don't have any open socket like this' and 
rejects it.


rather...

    client C sends packet with source address:C, destination address A, 
port P
    A forwards packet to B with src: C, dest: B, port P
    B replies to A with src: B, dest C
    A forwards response to C with src:A dest C,

and this response packet matches C's open outbound socket and is accepted