How to use two isps for two specific applications

[Dread10ck]

Hello,
I have two ISP's (ISP1: expensive, low bandwidth but almost 100% reliable and ISP2: very cheap and a little unreliable, )
I manage a 20 user (windows client) network with 1 windows 2003 server.

How do I dedicate one ISP (ISP1)to my mail server exclusively and retain the other ISP (ISP2) for general uses such as web browsing and other such.

Thanks.

 

[eibgrad]

So I assume you have two routers, each associated w/ different ISPs. So how are clients choosing among these ISPs currently? Are they just arbitrarily configured for one or the other by DHCP? Are these routers offering DHCP service, or has that been centralized on the windows 2003 server (it would seem that would have to be the case since you can't have multiple DHCP servers on the same network)?

Just trying to get a feel for the current configuration since you had to solve some of these problems already, even if incomplete.

 

[sturm]

Put two nics in your mail server. Run one to ISP1 and the other to your network. hard set appropriate IPs on each nic. Set gateway on the ISP1 connection and NO gateway on the 2nd
On the 2003 server setup DHCP with the gateway leading to ISP2. All clients will use ISP2 and Mail Server will use ISP1.

 

[Dread10ck]

@ebibrag I understand. I obviously have to elaborate a little more Clients don't have a choice. They are configured for any parameters I want them to have via server based DHCP (from Windows Server 2003).

At the moment everything goes through the expensive but reliable ISP1 via my only router (I was considering buying another router for ISP2 but I suspect that I don't really need one).

I just wanted to hear from someone who had tried this successfully as I don't wan't to experiment on a live network and don't have the resources to experiment elsewhere!

 

[Dread10ck]

Put two nics in your mail server. Run one to ISP1 and the other to your network. hard set appropriate IPs on each nic. Set gateway on the ISP1 connection and NO gateway on the 2nd
On the 2003 server setup DHCP with the gateway leading to ISP2. All clients will use ISP2 and Mail Server will use ISP1.

Strum, thank you. Sounds brilliant. I believe this is the right thing to do. I'll try it and let you know.

 

[eibgrad]

Strum, thank you. Sounds brilliant. I believe this is the right thing to do. I'll try it and let you know.

Oh, I thought by mail server you meant a pop3 server. I didn't realize you meant your OWN mail server (e.g., Exchange). That would have been helpful to know. That's why I thought it was a configuration issue for the clients, not ONE server machine.

Note this exposes your mail server directly to the public IP space unless you take additional precautions. It should still be placed behind a firewall imo if at all possible (even another router preferrably).

Anyway, as long as it works.

 

[Dread10ck]

Best answer selected by Dread10ck.