IP forwarding

Hi everyone,

I have installed kvm on my ubuntu pc.
I have created 3 VMs, two on the 192.168.122.0 network and one on the 192.168.100.0 network



When a packet comes from 192.168.100.190 (outside.example.org) and goes to the 192.168.122.0/24 network the 2 VMs (server.example.com and client.example.com) see it as coming from 192.168.122.1 and NOT from 192.168.100.190 as expected !!

Examples:

When I run a ping command from 192.168.100.190 (outside.example.org) the output of the tcpdump command on 192.168.100.103 shows this:

# tcpdump -i eth0 -v icmp
tcpdump: listening on eth0, link-type EN10MB (Ethernet), capture size 65535 bytes
14:40:57.249450 IP (tos 0x0, ttl 63, id 0, offset 0, flags [DF], proto ICMP (1), length 84)
	192.168.122.1 > server.example.com: ICMP echo request, id 13, seq 1, length 64

When I send an http client request (elinks browser) from 192.168.100.190 to the httpd server on 192.168.100.103 the logs file on this shows :

192.168.122.1 - - [06/Apr/2014:14:39:43 +0200] "GET / HTTP/1.1" 200 17

Any idea ?