Written 25 Aug 2026. This is a how-to, not a product card. Buy links are not tagged yet.

Keep the leftover box on the same number

SSH and Pi-hole keep working after a reboot when the router always gives the leftover box the same address.

You already found the leftover box once. That was find the leftover box on the house network. Then you SSHed with that number. After a reboot, the number may move. This note is how to tell the house router to keep handing out the same one.

Why the number moves

The house router hands out addresses for a while, then may pick a new one when the leftover box comes back. You reboot after updates, or the power blips, and suddenly SSH from the couch fails with the number you wrote down. Find the leftover box works again, but you should not have to hunt every morning. Pi-hole is the same story: the house looks for the box at the old number and ads come back.

What a DHCP reservation is

DHCP is how the router hands out numbers on the house network. A reservation means this leftover box always gets the same number. The box still asks the router for an address. The router just always answers with the one you chose. You do the work on the router, not by typing a static address into Linux on the box. Router menus call it Reserve, Always use this IP, or Static lease. Same idea.

Do it on the house router

Open a browser on your normal computer. Log into the house router with the address on the sticker, often 192.168.1.1 or 192.168.0.1. That password is on the sticker, or the one you set. Find the client list, device list, or DHCP list. That is the same list from find the leftover box on the house network.

Find the leftover box by name or by the number you already use for SSH. Choose Reserve, Always use this IP, or Static lease. Keep the number you already use. Do not invent a new one unless the old one is already taken. Save.

Then reboot the leftover box, or wait for the lease to renew. Reboot lives on shut down the leftover box without yanking the plug. When it is back, SSH again with that same number.

Check

From another computer on the house network, knock three times with the known number:

ping -c 3 192.168.1.50

Swap in your real number. Then SSH the way SSH from the couch taught you. If ping fails, see is the leftover box still on? before you touch the router again.

What next

If Pi-hole is not up yet, that is the first useful thing on the leftover box. If password SSH has been boring for a week, log in with a key, not the password every time. If the leftover name is still ugly, give the leftover box a name that sticks. If the leftover is still on Wi-Fi, plug a cable: a cable beats Wi-Fi for the leftover box. Do not buy a NAS for this.

Skip

Skip this note if SSH already works every day with the same number, or if the reservation is already set.
Skip typing a static IP into Linux on the leftover box for a first pass. The reservation on the router is enough.
Skip a new router.
Skip buying a Pi-hole just for this.
Skip a managed switch for this.

Sources

Router UIs differ, so stay on the sticker login and the client or DHCP list. No fake vendor docs. For the address hunt, see find the leftover box on the house network. For the login, see SSH from the couch. For Pi-hole later, see the first useful thing on the leftover box.

Also on this topic

A cable beats Wi-Fi for the leftover boxOnce the leftover box is doing real work, plug it into the router with a cable. House Wi-Fi can wait. Skip this if it is already on a cable. Find the leftover box on the house networkThe leftover box has a number on your house network. You need that number to SSH from the couch. You do not need a new router. SSH from the couchType commands on the leftover box from your laptop, on the house network. Password login first. Do not open this to the internet. The first useful thing on the leftover boxPut a house-wide ad block on the leftover box. The rest of the house keeps using the internet as usual. You do not need a Raspberry Pi.