I have a client that has contracted 2 ISPs for a small office with 8 workstations. He does web site development but not the hosting. He wants me to setup the following so that the second ISP is always available as a backup:

  • On the modem/router of ISP-1, set the LAN IP to and disable DHCP.

  • On the modem/router of ISP-2, set the LAN IP to and disable DHCP.

  • Connect each modem/router by cables to LAN ports on a Belkin N+ router and enable DHCP.

  • All the workstations have fixed IPs set in each workstation's network config. The workstations are 4 Macs, 2 Windows, 2 Linux Ubuntu. Each programmer will choose which ISP to use by specifying the gateway ( or in the workstation network config.

FYI The client used to have a Peplink Balance 20 before my time. I put in a TP-Link TL-R470T+. The client just wants to pull the TP-Link and try this. Any chance it will work? What can I tell him?

The next objective is that the head programmer (Linux) can SSH to the Test Bed Web Server (also Linux) from outside the office via either ISP.


Yes it can work. A few points to notice.

1.Disable DHCP on both modems, while you leave it on on your router; make sure the range of addresses to be served does not include and; also, choose as the LAN subnet;

2.Disable the Router function of your router; it must act as a pure switch,i.e. it routes packets at the layer-2 level, via MAC addresses, not IP addresses;

3.Connect the cables from the modems to the LAN-side ports of the router; leave the WAN side of the router empty.

4.Assign an IP address to your router, so that you can always reach its GUI.

If the company employees are savvy enough to choose their own ISP (and router), then no problem.

  • You can also configure their machines to have 2 gateways with different weights. Windows for example will switch to it's second if the first fails. I am not sure how to do it on the other machines. – Andrew M. Jan 28 '14 at 20:48

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.