I am not quite sure if this issue relates to iptables, routing or Xen virtual machines. Too many variables for my simple mind, so I'm asking some advice :)
This is my network setup:
Internet --- eth2 + CentOS dom0 / firewall / router + eth1 (xenbr1) --- LAN with private IPs --- separate file server and workstations + eth0 (xenbr0) | DMZ network with public IPs --- CentOS6 domU web server
Lets assume my dom0's eth2 public ip is 1.2.3.33 and my dmz network 11.22.33.96/255.255.255.224 . I have created NAT from my LAN with iptables. You can see my /etc/sysconfig/iptables here: http://pastebin.com/1FqSTvPH
And this is my routing table:
# route -n Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface 1.2.3.32 0.0.0.0 255.255.255.252 U 0 0 0 eth2 11.22.33.96 0.0.0.0 255.255.255.224 U 0 0 0 xenbr0 192.168.0.0 0.0.0.0 255.255.255.0 U 0 0 0 xenbr1 169.254.0.0 0.0.0.0 255.255.0.0 U 1004 0 0 eth2 169.254.0.0 0.0.0.0 255.255.0.0 U 1005 0 0 xenbr0 169.254.0.0 0.0.0.0 255.255.0.0 U 1006 0 0 xenbr1 0.0.0.0 1.2.3.34 0.0.0.0 UG 0 0 0 eth2
My goal:
To access NFS shares on a (non-virtualized) file server in the LAN network from the domU web server in the DMZ network.
What I tried:
I attached the domU to both bridges using this Xen config:
vif = [ "mac=00:0c:29:de:3a:fe,bridge=xenbr0","mac=00:0C:29:76:19:85,bridge=xenbr1" ]
and then created two eth interfaces inside the domU mapping to the MAC addresses above, giving eth1 an IP from the DMZ (11.22.33.111) and giving eth2 an IP from the LAN (192.168.0.12). After this I mounted the NFS share from the file server (192.168.0.2).
My problem:
If my domU web server is connected to both LAN and DMZ using the two bridges xenbr0 and xenbr1, I can access the NFS share from the domU web server and everything else works as expected, except for one thing -- my workstations in the LAN cannot anymore access the web server: web pages do not open anymore and from the workstations I cannot ping the domU. If the web server domU is only connected to DMZ via xenbr0, the workstations can access it ok.
Any advice what I am doing wrong and I could fix my setup?
Regards, Peter