Re: RH7.1 / 2.4.5 / ipvs

["Carlos Maynard" <carlos@xxxxxxxxxxxxxxxx>]

(**it was supossed to show up as a table**) ;-)

 

Hi there Nick...

I think it has something to do with the Real server's default gateway being
the Director.

If the real server has a local interface in the network where the webpage
has been requested... it will send the webpage directly.
And the source IP is going to be different than the one the Web Browser is
expecting... and therefore from the Webserver's point of view... the
webserver is not replying.

For example:

VS = 100.100.100.1
RS1=1.1.1.1
RS2=1.1.1.2

Client:    200.200.200.1

 

On the VS

PacketSource	PacketDest	Info
200.200.200.1	100.100.100.1	The Web browser on client1 request a webpage.
200.200.200.1	1.1.1.2	The VS selects a RS and sends the package to it. Setting packet's destination Address to the RS IPAddress.

Then On the RS:

200.200.200.1	1.1.1.2	The request from the VS arrives.
1.1.1.2	200.200.200.1	RS replies to the request... sending the packet back to the Client But the packet is going to pass thru the VS (default gateway rule).

Back on the VS

1.1.1.2	200.200.200.1	The VS receives the packet from the RS.
100.100.100.1	200.200.200.1	The VS forwards the packet to the client. Setting packet's source Address as his own IPAddress. so the client is going to receive the packet from the "Server" it requested it from.

Now the point is... at the end of the transaction, when the packet is sent back from the RS to the Client. If the destination ip address is in the same network where the RS is... (i.e. 1.1.1.3) then the packet is not going to go thru the default gateway (Virtual Server) and therefore the packet is going to arrive to the Client's Web browser but with the wrong Source Ip Address.

 

That's just a thought. I might not be making too much sense...
Please remember.... i'm Brand new to IPVS....    :-)

Regards,