Two ISP connections

[James]

> Hello.
> I have a server with two ISP connections: a flat ADSL with an ISP and pay-per-traffic HDSL with another.
> I'd like to use ADSL whenever possible, but switch to HDSL in case the first line drops.
> Any pointer?
> 
>  bye & Thanks
>         av.

Write a script and cronjob it to check every 5 minutes.

The script should:

   a) ping both ISP gateways or use other means to check connectivity
   b) If the primary connection is down, remove the default route and
      point the default route to backup ISP.
   c) If using NAT, flush the nat rules, and re-map the internal network
      to backup ISP's IP address.
   d) If the primary ISP is back online, do vice versa to switch back.

That's one way of doing it. You can also write a daemon too that's more robust
than a simple shell script.

-J

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James Jun (formerly Haesu)
Network Operations
TowardEX Technologies, Inc.
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