Re: Sharing ISPs

I have succeeded in using two ISPs by setting the default gateway merit for
the faster ISP below the one for the slower. I then added some of the slower
ISP's networks to the routing table using a merit value that was below
either default gateway, but pointing to his gateway.

This seems to work very well since I can use tracert to see which gateway is
being used for any specific destination. All I had to do was re-run the SBS
connection wizard to make ISA accept this scenario without complaining!

Those URLs you provided seem to indicate that the problem of one ISP failing
is already taken care of. They also explain why the default route
mysteriously changes by itself if I don't set the merit values far enough
apart. THANKS!

Now if only I could dynamically "bump" the default route for every third
outgoing TCP connection request (SYN flag set) to send it out the slower ISP
to do some load sharing. This simple feat alone would go a long way in
improving my total bandwidth while avoiding extra equipment purchases. That
is the purpose of my posting to this forum.



"Phillip Windell" <philwindell@xxxxxxxxxxx> wrote in message
news:OreL9kleJHA.3520@xxxxxxxxxxxxxxxxxxxxxxx
"rg" <rg@xxxxxxxxxxxxx> wrote in message
news:eSjE10IeJHA.6012@xxxxxxxxxxxxxxxxxxxxxxx

Anyway, I thought SBS meant "Small Business Server," the single platform
solution to all the needs of a small business. I'm not asking about "Big
Business Server Facility" where we have separate RAS, Exchange, Web,
etc., platforms and all the fancy hardware that goes with it.

There's marketing,...then there is the real world. It is "Small Business"
because of the limitations built into it. It doesn't meet *all* needs of
a small business,...it meets the needs it was designed to meet,...there is
a big difference there.

The duel ISP thing has nothing to do with SBS. SBS is not a Server, not a
"Router",...when you add ISA to it you have a Firewall and a simple "low
end" LAN Router.

The newer "home user" NAT Boxes have been incorporating line failover for
may a year or so. Commercial grade Routers have always been able to do
this but they do it with Dynamic Routing Protocols like RIP, IGRP, OSPF,
etc.

Without an upstream device built to handle this you are stuck with the
abilities built into Windows,...and ISA just depends on Windows for that.
It is clunky, undependable, and not likely to satisfy what you are looking
for,...hence why we hardly ever mention it and the standard answer is "No
you can't do that".

I couldn't verify it with these articles, but the multiple Gateways may
need to be on the same subnet on the same Nic,...which is not going to
happen with two ISPs.
Here's the links if you want to "punish" yourself with trying this:

128978 - Dead Gateway Detection in TCP/IP for Windows NT
http://support.microsoft.com/default.aspx?scid=kb;EN-US;128978

171564 - TCP/IP Dead Gateway Detection Algorithm Updated for Windows NT
http://support.microsoft.com/default.aspx?scid=kb;EN-US;171564


--
Phillip Windell
www.wandtv.com

The views expressed, are my own and not those of my employer, or
Microsoft,
or anyone else associated with me, including my cats.
-----------------------------------------------------






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