Your Synology Router suddenly changed its subnet range (e.g., from 192.168.1.0/24 to 10.0.4.0/24).

If Synology Router detects a subnet conflict, it will automatically change the subnet from its default range to avoid disconnection from the Internet.¹

On SRM 1.2

Synology Router will change the subnet from 192.168.1.0/24 to 10.0.4.0/24. If the conflict keeps happening, Synology Router will continue changing the subnet from 10.0.5.0/24 through 10.254.254.0/24 until the subnet conflict is resolved.

For example:

On SRM 1.3

On the primary network, Synology Router will search for a usable subnet from within 10.0.0.0/8. If the conflict keeps happening, Synology Router will continue changing the subnet starting from within 172.16.0.0/12 until the subnet conflict is resolved.²

After the primary network has found a usable subnet, the guest network will continue as described above until a usable subnet is found. For example, if the primary network has found a usable subnet at 10.0.4.0/24, the guest network will continue searching from 10.0.5.0/24, through the three types of private networks (10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16 in this order) until all private network IP addresses in the Classless Inter-Domain Routing (CIDR) have been tried.

For example:

If you cannot find your Synology Router with its original IP address (e.g., 192.168.1.1), try to search for it via router.synology.com.

If you want to keep the subnet range of your Synology Router’s primary network at 192.168.1.0/24, do the following:

1. Make sure that your parent router/modem dispatches another subnet range other than 192.168.1.0/24.
2. In SRM, go to Network Center > Local Network to change your IP address and subnet mask.