Dynamically reconfigure WAN routing via script?



  • Does anyone know if there is a way to dynamically reconfigure multi-WAN routing via a cron script, scanning for route changes?

    I am in a rural area with absolute crap for Internet access. I need a low latency, high speed connection, but all we can get for landline service is 1.5 megabit DSL. Also we are in a situation that if we dropped the DSL, we would probably never get it back due to others wanting it, and no additional capacity available.

    I am looking into getting cellular broadband from AT&T, which is going to be quite expensive and limited in capacity. I don't want to be wasting this on unnecessary data that I don't care about, so what I am planning to do is use both the DSL and the Cellular broadband together in a multi-WAN configuration. All the unnecessary background data will be routed through the DSL.

    One of the biggest bandwidth burners is Microsoft Windows updates. Microsoft does not publish addresses / network-CIDRs for their cloud services, but it is possible to get those addresses via nslookup queries of their various DNS addresses, as described here:

    https://social.technet.microsoft.com/Forums/windows/en-US/b596aa81-2775-496c-b159-dcfc5c5bf22d/windows-update-ip-addresses-range-and-subnet-mask-for-windows-server-2008?forum=winserversecurity

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    I could go through this list, manually do an nslookup for each one, then retrieve the addresses and enter routes for the DSL..

    But if these Microsoft cloud addresses randomly change at some point, then they will start eating my precious limited cellular data.

    I do not want to have to periodically recheck these routes by hand once a week to catch any changes.

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    There must be some way to automate this process, to daily run an nslookup for these and other "bandwidth hog" DNS names (Adobe update, iTunes update, Autodesk update, etc), then automatically reconfigure the routes directed through the DSL.