Backroute

Backroute is a lightweight shell script, that monitors a primary router, and switches to a backup router and back as the primary router comes back online. Backroute is for you, if you want to have automatic router failover to a backup router, but want to avoid the complexities of dynamic routing daemons.

Typical usage scenario:

• you have a new, fast (ADSL oder cable) internet connection, which sometimes may fail.
• you have a backup internet connection (ISDN or even modem), which is not used anymore.
• you have a linux server, which handles things like dhcp, smb filesharing, www proxy, etc.
  

Principle of operation:

• The linux server is entered as the default gateway of all clients. Since the linux server adapts it's routing automatically, clients will no longer notice when the fast router goes offline.
• Automatic changing of the linux server's routing table:
  • a static route to the next upstream router is entered into route.conf.
• backroute shell script is called regulary as a cron job and:
  it checks the next upstream router
  • if upstream router fails, the routing table is changed to switch to default route to the backup router
  • if upstream router is back online, the routing table is changed to the fast router

Download

Version 1.1: backroute.tar

Backroute is licensed under GPL. Also check out the project page at www.freshmeat.net

 

Installation:

• Please see the README file in the tar distribution. Basically, you just copy the script to a location of you choice, change some configuration variables, test it and add a cron job once everything works.

Caveats:

• As you switch routers, your clients may experience problems when sending mail. This is because your ISP's smtp server will not accept mail if you come from an "alien" IP. See the README for a fix for this type of problem.
  

Comments

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