Every Guide Says "Reserve the Address on Your Router." What If the Router Is Not Yours?

This guide addresses the issue of maintaining a consistent IP address for an Android phone used as a security camera, particularly when the router is not under the user's control. Many guides suggest reserving an IP address within the router's settings, but this advice may not be applicable in situations where the user cannot access the router's admin page.

In cases where the user cannot log into the router, they can still run the phone as a camera, but will lose the convenience of a permanent, never-changing address. Instead, the user should learn to read the phone's current address from the phone itself, keep the phone continuously on the network to prevent address rotation, and only manually set the address on the phone if necessary.

This is because the phone's IP address changes due to the Dynamic Host Configuration Protocol (DHCP) allocation mechanism, which does not guarantee the same address for an extended period.

The problem lies with the router, not the phone. The router may reuse addresses after the lease has expired, the router might not remember leases after a restart, or the camera may not be assigned the same address if it leaves the network for an extended period. The issue is rarely related to Android's MAC address randomization, as the phone typically presents the same identity to the router every time.

The only real exception is when the developer setting "Wi-Fi non-persistent MAC randomization" is enabled, which re-randomizes the phone's address under specific conditions, such as after the DHCP lease duration has expired or if the MAC address for a network profile is more than 24 hours old.