Fail over scripting

RouterOS Scripting
1

I kow it has been accomplished by moving gateway metrics, but i am looking for a basic failover method.

I have a main (cable) and a backup (cellular) connection. I am looking to script a ping every 5 seconds or so that looks to the outside world say google, if that fails, it will switch to the backup connection.

The only examples I see ping the gateway, I have tried this but been unsuccessful, perhaps I am doing it wrong.

2

Hi, i’ve tried two different methods:

  1. By assigning to every interface a route and then routing traffic through it with different metric. That actually works.

  2. By applying VRRP, different solution - equal result.

But the question that seems that no one can answer is: How to do a smart failover checking link quality?

I have a similar issue, i’m having 3 differents WAN but it always chooses that one that have the lowest metric, and can’t choose the one with the best performance.

I mean, if i have 80% loss over number 1 metric - Traffic goes over there anyway.

3

Thank you for the reply,

I am currently doing mangle fail over but the issue seems to be it will only failover if my modem or gateway is not reachable, I need a script that will ping the outside world. (i.e Google or nist)

Wan1 is a cable modem
Wan2 is a cellular backup.

Most of my outages have been beyond the node gateway of the cable company. because the Mtik can see the cable modem gateway it doesn’t redirect the metric.

4

If you are able to evaluate the link quality, why not to set the distance metrics according that?

5

Good point, if you already know who is the main ISP you only have to assign it the lowest metric.

Example:
[admin@Router] > ip route print

DST-ADDRESS PREF-SRC GATEWAY DISTANCE

0 A S 0.0.0.0/0 [IP GW main] 1
1 S 0.0.0.0/0 [IP GW bk ] 2


Then you can do something else, you can set the "check-gateway ping" for both conections.

In your main ISP, i see that you don't have any trouble... you already did it.

But with your secondary (the cell) you should do this:

add dst-address=8.8.8.8 gateway=[IP GW bk ] scope=10
add distance=2 gateway=8.8.8.8 check-gateway=ping

So... when you send any request to 8.8.8.8 it will be always by the GW BK. Then you have to set 8.8.8.8 as a Gateway (to get a reference IP) and you can now set check-gateway=ping

That is a homemade and easy way, but i recommend you to read about vrrp that is what you need to apply in this scenario.

Regards.