[maaarghk]

You can set a static IP in your wireless settings.

[spockz]

Or ‘better’ fix an IP to your device MAC in your dhcp settings.

[gonvaled]

Usually not needed, since your router will usually try to assign a fixed address for already known devices.

[JdeBP]

What spockz said takes the words "usually" and "try" out of that. (-:

[gonvaled]

But means more work, with web interfaces of varying quality

[voltagex_]

What happens when the DHCP lease expires?

[gonvaled]

The router will try to reassign it, usually.

[andreareina]

Not all routers support this. In fact at work we've got a router that seems to black-hole anything whose source or destination isn't in the DHCP table (TP-Link 480t+).

In the end I solved this by accessing this only while I'm tethered, that fixes the phone's IP address.

Too bad there doesn't seem to be an option to select keys according to host key instead of hostname or alias.