I am running my application through internet, It's very important to use an uninterrupted internet connection. So
how can I set the Backup ISP to my router(Dual WAN or 3G/4G modem) to connect automatically when first ISP is down?
Thank in advance to your Response..
Actually I am using the DWR 116 router it has WLAN and 3G backup now i am fine with this, But the problem is this model going to be end in the market I am looking for this kind of solution
At the most basic level you will need to purchase a router that supports "WAN failover" as a feature. The problem with using this is that your IP address will change when you failover between ISPs, and at that point your web app/site will become unreachable a the old IP address, and users will have to start using the alternate IP until things are fixed.
If they're accessing it via a domain name, you'll (also) need a mechanism in place to update your DNS entries (and quickly).
My advice would be to discuss it with your ISP, as they can probably provide a solution that uses two different delivery technologies (e.g.: DSL and Cable, or DSL and 4G, etc.) but when the failover happens, your IP (as assigned by your ISP) will stay the same.
Couple of "Failover" Routers you can look at.
Liknsys LRT224 Dual Wan Router. Would just need to ISP feeds
Cradlepoint ARC MBR1400 has Verizon Sim Chip Installed
TP-Link TL-MR3220 You would need to provide a Cell USB Modem
The bottom two will utilize a cell data plan for fail-over. Might not be what you are wanting to use for backup.
For your setup, I'd use something like the Linksys Dual Wan that will support fail-over. If you can I'd get two Internet connections from different providers, one cable & one dsl. If you only have two cable Wan feeds, and service is down in your area. You are down on both ends.
For updating your domain address, i'd look at a DDNS (Dynamic DNS) client that you would run on your application server that would update the name entry when a fail-over happened. NO-IP.com is an example of a DDNS service
Only problem I can see, without knowing how long people are connected, would be what happens when someone is connected to your application and a fail-over happens.
I use the DUAL-WAN routers in small business that process credit cards, so have not had to deal with users being connected to a service/application you are running. My clients just need to get out to the Internet to process a credit card.
Still, talk to your ISP they might have a solution.
Also, I'd look into a cloud-server solution.
Hope this helps.
I've used a software firewall like endian.com (community version works great) that runs great on a surplus computer with 2 nics.
In the interfaces tab of the configuration page, you can configure the secondary NIC to become active based on a rule-set applied to to the first.
Example: If NIC 1 can't contact www.yahoo.com then switch to NIC 2
You can also configure segment preference based on protocol type
Example: Send all HTTP traffic over NIC 1, but email traffic goes over NIC 2
Hope that helps.
