Need help to setup a small cluster, problem accessing the Internet
 

I setup the gateway which has two interfaces, one with a real IP and the second one has an internal IP. I can access the Internet with no problems using the gateway machine. I have six machines with internal IP that use te gateway I mentioned above. They can connect to each other with no problems but each time I try to access the Internet using any of the internal machines I get the message "connecting ..." then delay for a long time after which I get a page load error.

I tried dig +short yahoo.com and it could successfully resolve the IP on the internal machines but the ping does not work and I get host unreachable.

All machines are running Ubuntu 8.04. Any help please?

Thank you

You need to be more specific about your cluster setup for anyone to help you with the firewall setup.

Is it simply n boxes behind a firewall, or is it a true clustered setup where the cluster can be contacted via a single "virtual" IP address which acts as a "gateway" for the traffic coming to and from cluster?

Is the "cluster" really a server farm being load balanced, or is it a true clustered setup?
Is there a discrete load balancer?
Where is the LB located? (in subnet with servers, outside of your network etc.)
What type of load balancing are you doing?(packet header munging, dns redirect, round robin etc., is it a load balancing switch or router based? What layer is the load balancing occuring at?)


To help out we need exact details about how your load balancing is to work as well as details about how the IP addressing is setup (though not necessarily the correct addresses, only for illustrative purposes).

The reason for this is your firewall config could be drastically different depending on how you are load balancing.

Give up the details 8) A text diagram put within code tags would be very helpful.

If the cluster presents a single IP address to the user, things could be as simple as a port forward (which is very secure and easy to set up)... if the user gets redirected to any one of n IP addresses things get a little more tricky and a different type of firewall setup is required.

-Viz

It sounds like IP forwarding has not been enabled on the gateway machine. Also, there's no indication that you've setup NAT, which will be necessary on the gateway machine, otherwise it will pass unrouteable traffic.