In this configuration single computer gateways will be used for each WAN link. These computers will have a NIC for the WAN and a gigabit NIC for the internal network. Xion will likely be used for the Quest DSL link since it has higher outbound speeds and Hal will be used for the Comcast WAN because of faster download speeds.
The Apache server on Xion will listen on the WAN NIC and on the Gigabit NIC side as well. Hal will be configured to NAT incoming http traffic to this. If the Quest link goes down, the ddclient script will update zoneedit.com to point to the current alternate Comcast IP and NAT routed appropriately through Hal.
We are assuming both 'gateways' will be able to relay DNS services to the internal network, and all internal devices will have Xion as the primary DNS and Hal as a secondary DNS. We are assuming that internal computers will be able to specify default and secondary routs and gateways through these systems in a load balancing way.
This solution has the best redundancy allowing most of the system to remain functional if any single part fails. If a second Xion mirrored system is added, this would likely take over the secondary services from Hal providing complete redundancy of everything.
Remaining questions and unknowns:
- What software can be used to handle:
- NAT to internal Gigabit network software for both Linux and Windows.
- DNS forwarding and failover on both Linux and Windows.
- Appropriate routing of outbound traffic.
- Failover detection and reconfiguration for all possible failure modes.
- Will it be possible to leverage or load balance all or at least some available bandwidth for personal downloading without effecting Canonizer services? If so, how?