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Two ISPs (single IP each) and two SSL sites on two servers - can ISP failover be done with ISA?

Last Modified: 2012-05-06
Dear Experts,

I am running two Windows servers with an SSL site each (one Exchange OWA, the other one with an ASP.net application). Each server has its own internet connection with a single IP address. There are two routers installed at the moment. So far so good.

I would now like to make the internet connections (somewhat) failsafe, i.e. if one ISP goes down, the server should be reachable via the second ISP. (The DNS entries are hosted by our domain providers, so I could live with different hostnames for "normal" and "failover" modes, e.g. www for normal- and www2 for failover-mode, if needed.)

I understand (correctly?) that if I go out and buy a dual WAN router (e.g. a Cisco/Linksys RV042) I would get ISP failover for outgoing connections. For incoming connections I think I would need to set up port redirections, as I only have one public IP remaining when one ISP fails. SSL would then not be possible anymore, creating a further degree of complexity.

Wouldn't it be better to set up another PC with ISA that connects to both ISPs and which handles the routing, failover, SSL redirection, etc.? I need to add that so far I haven't touched an ISA server yet (this is not to say that I'm afraid of this, I just have never done that and don't know the full range of features and functions ISA gives me). If you feel that ISA is the right way to go for my given application, I'll start learning ISA :-)

Thanks a lot for your advice.

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