1 computer to 2 ISPs via 2 phone lines?

I've got 2 'phone lines and at the moment each has a broadband service set up on it. I've also got 2 ADSL modem / routers. (A solwise SAR 715 and a Speedtouch 546). So I'm wondering if I can connect 1 computer to both internet connections at the same time.

I've been running a fixed rate broadband connection on one of the 'phone lines. But it turns out that the other 'phone line has a better line quality for ADSL Max purposes (a better attenuation figure), so I've gone for a Max service on it. That's a new service with a new ISP. That leaves me with my old fixed rate broadband connection with my original ISP on the other line. Rather than cease it and lose the ADSL set up on the line at the exchange, I'm toying with the idea of migrating it to a provider with a simple "pay as you go" type service. If I use 2 different ISP's that would give me a back up service for those times when there are glitches and outages etc.

I've got some spare network cards, so I can put a second network card in my computer easily enough. So in theory I can run the ideal setup of two networks each running out to its own router to its own 'phone line to its own internet service. I'd like to keep both active at the same time so that I can simply switch between them from my desktop rather than by having to plug and unplug cables at the back of the computer etc. But would it work? Or would I be heading for a technical nightmare?

do you know how to do load balancing between two networks on your PC's operating system ? if not you might find a load balancing router or similar twin-WAN device helpful.

If you just want to switch between them then set one router as 192.168.0.1 and the other as 192.168.0.2 and change the default gateway setting on the PC to whichever you want to use. A single network card will suffice, and a patch lead between a LAN port on each router.

That was a quick reply! Thanks - much appreciated. It's the ability to switch between connections that interests me. Having a back-up connection quickly available appeals to me - gone are the days when I maintained a dial-up modem on a com port ready to run in case of need. Your default gateway and patch lead suggestion looks like a nice elegant solution - I wish I'd thought of that!

the back up idea only works if its the provider thats having issues. Your two connections most likely go through the same exchange, line and route so if theres an issue on one (outside of provider) then the other one will most likely have an issue too.

As to suggestion.
My router (zyxel p2602hw) has the option of defining a second gateway if the primary goes down which it will then redirect to, might be worth checking to see if the option is in one of your routers too.

Not always true. I have two lines and have had one fail due to fault at the exchange leaving the other on OK.

Add to that the DNS settings on the computer to use one ISP as the primary Name Server and the other ISP as the Secondary and you have a bit of automatic fault redundancy.

Manually switching between gateways is easy and quick on Windows XP. (no dreaded restart)

Re:- "gone are the days when I maintained a dial-up modem"

Long time since I used it for real but I still have it set up through a software router on a Windows 98 box. Just need to change the gateway as suggested elsewhere.

(Depending in the router you can even do the re-routing by changing settings on that.)

e.g.
All PCs use ADSL router as gateway,
ADSL service is dead, so manually set router to route all outgoing requests to Win98 box
Win98 box routes all requests to Internet via dialup.

SLOW but it gets there.

Wonderful thing routing! Play with it all day..

Some interesting ideas to play with - thanks folks. I'm taking a half term holiday break with the family at the moment, so internet tinkering time will have to wait for a few days!

Hi, I have 4 network connections installed for broadband made switchable on my Windows XP Pro computer.

1 3Com EtherLink 10/100 3C905C-TX NIC PCI Adapter.
1 3Com 3CRDAG675B Wireless LAN PCI Adapter.
1 BT Voyager 1040 Wireless PCI Adapter.
1 D-Link AirPlus G DWL-G122 Wireless USB Adapter. (I am testing this adapter for a friend).

The PCI adapters wired and wireless connect at 100 Mbps, the USB Adapter only connects at speed 54 Mbps.
I have a shortcut for each connection placed on the desktop created from within Windows control panel

Edited by deleted (Fri 02-Nov-07 18:34:49)

As you obviously have experience of this, does this mean that you can leave each ISP and network link running on the same computer at the same time without detriment?

My set up is two lines, two ISP, 2 modem and a choice of wireless or hardware routers, plus the option for dial-in if all else fails (which would be unlucky or BT digging up the road outsiide) . I have a hardware firewall I would like to add, but need to get the set up running seamlessly first - which it ain't, mainly because of my ignorance and tendency to forget one day what I learned the first.

Generally have no more than two and never more than five computers networked at the same time. However, I started to use Network Magic, which does not seem to like a computer to be linked to more than one modem or network at a time (using an away from home description). My laptop wireless manager also seems to disable itself to avoid conflict with Netork Magic. I am beginning to wonder if I should actually dispense with Network Magic and rely on XP especially as it seems to insist on repairing broken connections in a very fundamental way (disconnecting modem etc). Windows 2000 never did that. Iis there any simple way of switching between the two ISP's on the same computer without breaking connections or disabling networks?.

At the moment, I disable one network before tapping the other, especially when performing a comparative speed check between the two ISPs, but this is a real pain.