Hello!
I use NS 7 + latest updates!
I have two wan connecting, main and reserved!
MultiWan configured as Active Backup.
Everything works, everything is fine!
If failure of the main wan connect, its switches to reserved wan.
My suggestion is what it is.
I have in the organization of more than 200 Internet users.
My reserved wan is very slow…
I want that when switch to reserved wan, work only specific users and/or group users,
and/or specific websites.
Sorry for my English…
well not sure it is implemented, your request is a bit specific but interesting, @giacomo some clues ?
One option would be to create two different zones for each WAN connection and define which host or subnet can access each zone.
Not sure if this will work, best way to know is to test it.
Actually, another way is to use Firewall Rules
You could do it as James suggested, but as far as I understand you need dynamic rules that are activated when the main wan goes down.
The only way to it, is adding on-the-fly rules using a script inside the wan-uplink-update event (/etc/e-smith/events/wan-uplink-update/).
It’s not easy, and it requires a little of programming skills and iptables knowledge.
My advice is to simply the whole configuration, and give low priority to all non-important users using the traffic shaping feature.
Yes 
how to do it?
Just create the priority rules from the Firewall rules pages.
it will be a permanent rule
I want to work only on a specific interface wan