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On Sat, Sep 09, 2000 at 02:03:24PM -0500, David D.W. Downey wrote:
>
> OK, I'm using NAT based LVS right now for the company website.
> Could someone explain to me how Direct routing works? (Is that for FOS
> only or can it be used in LVS mode?) If I understand DR right, it takes
> the incoming packet(s) and shunts them directly to servers on the backenbd
> which ALSO have to have real FQIPs correct? If this is true, how is it
> doing the routing BACK to the requesting client? How can one save state
> information between the client and the responding server?
Basically DR works as follows
* Client connects to Linux Director
* Linux Director selects a back end server and sends the packet to it.
Think of this in terms of forming a new Ethernet Frame and pushing
it onto the wire. The IP packet remains intact.
* Back end server receives the packet and terminates the connection.
There are several methods of convincing the Back end server to treat
this packet as local traffic even though it has the destination IP
of the virtual IP address. Two of these methods are:
Set up a hidden interface for the VIP
Use Transparent proxying
* Back end server sends response directly to client.
All the forward packets follow the data path:
Client -> Linux Director -> Back End Server
All the return packets folow the data path:
Back End Server -> Client.
--
Horms
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