How does missing gateway affect guests?

[ScotofMKE]

This is a question that I am not able to test in a production environment, but would like an answer to.  If a firewall and its gateway IP used for a virtual host (we'll say 192.168.0.1) becomes unavailable, will that in any way block workstations from accessing virtual guest servers on the host that are using a different gateway (192.168.0.13)?  It doesn't seem like it should, but I had a similar problem that made me believe otherwise.

[mcowger]

Depends.  If all the endpoint systems involved are on the same phsyical broadcast domain and the same subnets, they dont need the gateway to communicate, and so failure of that gateway wont impact (except for stuff like DNS, which could be impacted if its behind that gateway).

If they are on different subnets, they absolutely need all gateways in between functioning.

THis is no different from a physical network.

[ScotofMKE]

The two DNS servers we have setup use Forwarders for external IP addresses.  These two servers are configured with a gateway that was shutdown.  Even though the workstations pointed to a different gateway and firewall that was still running, if the gateway used for forwarding by the DNS servers was down, no DNS resolution would happen.  Does that seem reasonable, or is there some other path the resolution would happen through?

[DSTAVERT]

If the DNS servers had no way to access the forwarded DNS servers then no resolution would occur. They may be able to provide cached results but the cache would expire. Is there some special reason the DNS servers were using an alternate gateway??

[weinstein5]

Think of it this way - think of a gatway as a door that network traffic can come in and go out - so a network with no gateway is a closed room with no door to get out or in so the traffic will only stay on that network segment -

[ScotofMKE]

I have some workstations and all servers using one Internet pipe, and the others using another.  The internal DNS servers of course forward through their firewall, but when the firewall was brought down, it appears that ended the forwarding for domain resolution for the other firewall.