I am having a bit of a strange issue. I have a VMWare ESXi server with two virtual machines running on it. They are running just fine and can communicate on the network without a problem.

I am now trying to add a third. I am installing Ubuntu 8.04 Server. I assign it a static IP address and it's a fresh installation. Once installed I can ping the gateway but I cannot ping the DNS server. It's on the same network with the other two VMs which are communicating just fine. I have tried to reinstall the operating system but it still fails to connect.

Here is /etc/network/interfaces

auto eth0
iface eth0 inet static
    address 192.168.1.23
    netmask 255.255.255.0
    network 192.168.1.0
    broadcast 192.168.1.255
    gateway 192.168.1.1
    dns-nameservers 208.67.222.222 #opendns
    dns-search mydomain.com 

Here is route

Destination | Gateway     | Genmask       | Flags | Metric | Ref | Use | Iface
localnet    | *           | 255.255.255.0 | U     | 0      | 0   | 0   | eth0
default     | 192.168.1.1 | 0.0.0.0       | UG    | 100    | 0   | 0   | eth0

Since I'm running this behind a FortiGate this is what the sniff command gives me when I try to ping 208.67.222.222

arp who-has 192.168.1.1 tell 192.168.1.23
arp reply 192.168.1.1 is-at MAC
192.168.1.23 -> 208.67.222.222: icmp: echo request
192.168.1.23 -> 208.67.222.222: icmp: echo request
192.168.1.23 -> 208.67.222.222: icmp: echo request
192.168.1.23 -> 208.67.222.222: icmp: echo request
192.168.1.23 -> 208.67.222.222: icmp: echo request

As you can see it looks like I never get a response. One interesting thing I notice is the arp reply's MAC doesn't look right. I have cleared the FortiGate's ARP cache though and checked the entry and it seems correct. The MAC it lists is the one for the router. However if I ping from a different virtual machine that is also Ubuntu 8.04 with a nearly identical configuration I get this.

192.168.1.22 -> 208.67.222.222: icmp: echo request
208.67.222.222 -> 192.168.1.22: icmp: echo reply
192.168.1.22 -> 208.67.222.222: icmp: echo request
208.67.222.222 -> 192.168.1.22: icmp: echo reply
192.168.1.22 -> 208.67.222.222: icmp: echo request
208.67.222.222 -> 192.168.1.22: icmp: echo reply

So, what could I be missing?

Thanks.