Networking Question

Greg Kettmann greg at kettmann.com
Fri Nov 6 09:48:48 EST 2015


SHORT VERSION -

Would a Networking expert mind giving me a call (or I can call them) to 
discuss the best way to have two ISP's, on my home network, with the 
ability to easily switch back and forth?

Greg Kettmann (603) 496-6071

LONG VERSION -

Thanks in advance for any help.  I'm no stranger to networking, although 
more for flat networks.

For various reasons, including reliability, I have two ISP's.  In my 
original configuration I had two Gateways, GW1-192.168.1.1 and 
GW2-192.168.1.2 on one subnet.  I used DHCP for the primary GW1.  If I 
needed to switch I'd use static addresses, and point the Default Gateway 
to GW2 instead.  However, the wife approval factor (WAF) on this is 
fairly low as it requires intervention on my part (she runs Win7).

I have a few "old" wireless routers around so I fired one up.  I know 
it's not recommended, but I tried having two DHCP servers (specifying 
different ranges to avoid conflicts) but this didn't work and didn't 
allow me to reliably switch from GW1 to GW2 and back.  With that in mind 
I've broken things out into two subnets (GW1=192.168.1.1, 
GW2=192.168.2.1) each with it's own equipment. There is effectively no 
connection between them.  So, WAF is higher... pick a Wireless Access 
Point (WAP) and it defaults to one ISP.  To switch, use the other WAP.  
So far, so good.

The problem is the rest of the house infrastructure.  I have printers, 
servers and media devices.  No problem when using GW1 but the "new" 
network, and GW2 are currently standalone.

  In my lab I run VMware (ESXi 5.5 - free).  it's a very simple matter 
to have an Ubuntu machine with two adapters, one on the 1.1 network and 
one on the 2.1 network.  What I need help with is the routing rules and 
where to apply them.  Almost everything is on the 1.1 network so I think 
I only need rules, on the 2.1 network, to allow "External" or "web" 
traffic to go through the 2.1 GW2 and "local" or 1.1 traffic to get 
routed to the "other side".

That's where things get fuzzy to me.  On the "secondary" network the 
Default Gateway is set to 192.168.2.1, so that's where I'd need to add 
the routing rule(s) but that device has no access to the 1.1 network.  
The Linux box, with two adapters, isn't the default gateway so it's 
routing rules would only apply to it's own traffic (I think).  I don't 
understand the routed flow of traffic so I don't understand how and 
where to apply the rules so that traffic bound for 192.168.1.1 
(255.255.255.0) goes there and anything else goes out GW2 (192.168.2.1).

Could someone get me pushed in the right direction?  Any help is 
appreciated.  BTW, "you're doing it all wrong and you should be doing 
something else instead" is a perfectly acceptable response. I'm not 
proud, just curious.

I've read dozens and dozens of forums, and I've posted questions, but 
haven't found any clarity yet.

Thanks in advance for any help.

GGK

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