Written 26 Aug 2026. This is a how-to, not a product card. Buy links are not tagged yet.

When something broke, look at the leftover-box log

SSH works, but a house job does not. Ask the leftover box what it just said before you buy a monitoring box.

SSH from the couch works. A house job does not: ads are back, the share vanished, or a restart after a reboot did not help. Ask the leftover box what that program just said. You are not buying a monitoring box for this look.

Skip until SSH works

If ping fails and SSH hangs, start with is the leftover box still on? If you have never logged in from the couch, that is SSH from the couch. If the leftover box is off, fix that first. This note assumes you can log in from the couch.

Skip until you know which job failed

If you just rebooted and have not checked the house jobs yet, start with after a reboot, check the leftover box still does its jobs. If ads are back, that is when ads come back, check the leftover-box ad block. If the share vanished, that is when the house share disappeared, check the leftover box. This note is the next look when systemctl said inactive, or a restart did not help.

What this is

A log is a diary the leftover box keeps of what programs said. journalctl is the Debian/Ubuntu tool that reads that diary. You are reading recent words from one program. You are not installing Grafana. You are not buying a monitoring appliance.

Ask about one service

SSH in from the couch. Ask about the job that failed, not the whole leftover box. For house ad block:

systemctl status pihole-FTL

For the house share:

systemctl status smbd

Then read the recent diary lines for that same program. For Pi-hole:

journalctl -u pihole-FTL -n 50 --no-pager

For Samba:

journalctl -u smbd -n 50 --no-pager

-u picks the program. -n 50 is the last fifty lines. --no-pager prints them without a scrolling trap.

If the name is wrong

If the leftover box says the unit was not found, do not invent a fancy name. Ask which services actually failed:

systemctl list-units --type=service --state=failed

That list is the leftover box telling you the real names. Stick to the jobs this site already named: Pi-hole as pihole-FTL, Samba as smbd. Do not chase exotic unit names that are not on this site.

What to do with what you see

Read the last lines. A clear error about a full disk is see if the leftover box still has room, then clear old package downloads when the leftover disk is tight. Permission or firewall is turn on a simple firewall without locking yourself out. Otherwise copy the last error lines into a note for yourself and re-check the matching how-to. Do not paste logs to strangers on day one.

What next

Leave it. Skip a monitoring box. Skip a NAS. Skip opening SSH to the internet. Weekly habit stays keep the leftover box updated.

Skip

• Skip if SSH fails. That is is the leftover box still on? or SSH from the couch.
• Skip if nothing is broken.
• Skip Grafana or Prometheus tonight.
• Skip a second leftover box.
• Skip buying a KVM because a log line scared you.