Run the connection test first and read where it stops. That single detail tells you which half of the chain to work on, and it saves you rebooting things at random for an hour.
Settings > Network > Connection Status > Test Internet Connection.
- Fails at Obtain IP Address — nothing is reaching the router. Cable, port, or DHCP.
- Gets an IP, fails Internet Connection — the link is fine. This is DNS or your ISP.
- Gets internet, fails PSN Sign-In — your network is working. Check PSN's status page before touching anything.
Those three are genuinely different problems. Fixing the wrong one is why this takes people all evening.
If it fails at Obtain IP Address
Swap the cable first. Not because cables fail often in an obvious way, but because they fail quietly and it takes ten seconds to rule out. Use a Cat 5e or Cat 6 you know works, and listen for the click at both ends.
Then move to a different port on the router. Individual LAN ports die while the rest of the router carries on, and the symptom looks exactly like a console fault. Check the port's link light comes on.
Then power-cycle in order: router unplugged 30 seconds, brought up first and allowed to fully boot, then the PS5 — and shut the PS5 down properly rather than leaving it in Rest Mode. Rest Mode keeps the network stack alive, which means it keeps whatever stale DHCP lease is causing the problem.
If you're going through a switch or a powerline adapter, take it out and go straight to the router as a test. That's not the permanent setup, it's a way of finding out whether the middle box is the problem.
If it gets an IP but says no internet
The wired link is fine. Stop looking at cables.
Re-run setup and set DNS by hand: Set Up Internet Connection > Wired LAN > Custom > IP Address Automatic > DHCP Host Name Do Not Specify > DNS Manual, then 8.8.8.8 primary and 8.8.4.4 secondary. MTU Automatic.
Before you do, check whether anything else in the house has internet. If nothing does, it's your ISP and no PS5 setting will help.
Leave MTU alone unless you're on DSL or PPPoE. Setting it to 1473 gets passed around as a general fix and it isn't one — 1500 is correct for almost everyone. If you're on PPPoE and seeing instability, 1473 is worth a try, and revert it if speeds get worse.
If it connects but crawls
This is the case people don't realise is a separate fault. The console is online, the test passes, and the link sits just under a 100 Mbps link speed on a gigabit line.
Gigabit Ethernet needs all four pairs in the cable. 100Mbps only needs two. So when a pair is broken — a kinked cable, a bent contact in the plug, corrosion on a connector that's lived behind a unit for three years — the link doesn't fail. It negotiates down to 100Mbps and carries on working, which is why nobody suspects the cable.
Anything clustering just under 100Mbps is this, near enough every time. The number is the giveaway: real congestion gives you a messy figure that moves around, and a downgraded link gives you a hard ceiling.
Replace the cable, and check the ports at both ends for a bent pin while you're there. If it's still capped, try a different router port — the port can negotiate down for the same reason.
If Wi-Fi works and wired doesn't
That narrows it to three things: the cable, the router's port, or the PS5's Ethernet port.
Take the same cable and the same router port and plug a laptop into them. If the laptop gets online, the two you've just tested are fine and the console's port is the remaining suspect, which is a Sony repair rather than something you can fix. If the laptop also fails, you've cleared the PS5 entirely.
It's a five-minute test and it's the difference between buying a cable and booking a repair.
FAQ
Where does the connection test stop? That's the question to answer first. Failing at Obtain IP Address is physical; failing at Internet Connection is DNS; failing at PSN is Sony's end.
It gets an IP but no internet. Set DNS manually to 8.8.8.8 and 8.8.4.4. Check another device in the house first — if nothing has internet, it's the ISP.
Should I change MTU to 1473? Only on DSL or PPPoE. 1500 is right for most connections and changing it blindly causes problems rather than fixing them.
Wired is connected but only 100Mbps. A damaged pair in the cable. Gigabit needs all four, 100Mbps needs two, so a broken pair downgrades the link instead of breaking it. New cable.
Wi-Fi works, Ethernet doesn't. Test that exact cable and port with a laptop. That tells you whether it's the console's port or everything upstream of it.