Question Synology NAS unable to connect after changing ISP ?


Jul 14, 2014
Hello everyone,

I have been testing two different ISPs that we have had setup and paying for at the same time. These two ISPs was one, starlink and the other was a local county co-op.

Currently I have been swapping back and forth between the two different ISPs by unplugging the source router then connecting the other source router into our system. I have noticed that I need to restart computers and machines to have them be able to properly connect to the internet.

At this point, I have been testing the two ISPs but I have specifically been running into major issues with my Synology NAS. I am currently unable to now connect to my Synology NAS through the Original ISP where I have it setup to be networked drives on my current machine. I have done everything to my knowledge to try and get connected back to this machine without having to do a full reset of the machine itself.

I have attempted to turn off the machine by pressing the front of the button (not ideal at all) unplugging the networking on the back of the machine and then restarting. When I do this it still does not connect me back. Also have attempted to connect directly to the machine itself and it is not helping. Also connecting the other ISP and seeing nothing for the connection.
Going to be messy when you do stuff like that.

Likely you are using 2 different IP ranges for the lan like 192.168.1.x and 192.168.0.x are 2 very common ones used by routers. End devices get assigned IP by the router and unless they figure out somehow the router has changed they will continue to use the wrong one.

So to make it somewhat better I would change both routers to use the same IP range. That way you can swap the router out and it will cause less issues. You still have the problem that both router even though they are using the same IP have different mac addresses. The end devices figure this out a bit faster. The communication between your pc and the NAS though should not be affected because nothing changes.

If the NAS does not work on either network all I can suggest is to find the process that resets the IP address. If you manually set the IP it will only work on that one network.

So maybe a better way to test would be to run both ISP on the same network. So take one ISP and configure it like normal. Make sure everything works. Now take the second ISP router change its lan IP to say 192.168.x.2....assuming your main router is 192.168.x.1. Disable the DHCP function on the second router.

So at this point nothing hopefully changes everything uses the main router. On the device you want to test on change the gateway in the setting to 192.168.x.2. All traffic from this device will now use ISP2 and everything else will continue to use ISP1. If you really want to get fancy you can actually use both ISP at the same time
for different traffic. The magic command is ROUTE. I will let you look that up. You need to know that the default route is the entry and you need to put in lists of IP to go to the other ISP.
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