Home internet now runs the heating, the doorbell, the television and whatever the children are doing upstairs. When it goes, most households phone the provider before checking anything at all, then spend forty minutes in a queue to be told to turn the router off and on again.
Do the checks first. Half of these faults you can clear yourself in ten minutes.
Your internet is slow
If you are using an ISP-supplied router, that is where I would start looking. Most of them are built to a budget and want restarting more often than they should. Power it off at the plug, wait ten seconds, put it back on and give it five minutes to sync.
Here in the UK I have seen some genuinely poor hardware shipped by XLN and TalkTalk over the years. What you get depends on the nature of the beast you signed up to. The one comfort is that the path back to the exchange is usually Openreach’s regardless of whose name is on the bill, so the line itself is often better than the box terminating it.
Measure it properly
Before you can say anything is slow you need a number that is not contaminated by the rest of the house.
Disconnect everything else, wireless included. Then connect one computer to the router with a cable. Use a gigabit-rated cable and a gigabit port, because a 100 Mbps link will cap you at around 94 Mbps and send you chasing a fault that is not there. Then run the test. We cover how to get a result worth quoting in how to test your internet speed.
Look under the bonnet
Still slow after a restart? Time to log into the router, which is less frightening than it sounds.
The login details for ISP-supplied routers are printed on the back. For everything else there is our default password directory, no pun intended. Failing that, the manual you have definitely kept somewhere safe.
Find the page showing the SNR margin. On DSL and FTTC you want something in the region of 6 dB. A margin much higher than that, say 18 dB, means the line has detected noise and backed itself off to stay stable, and you are paying for that stability in speed. The same page records the rate the router negotiated when it last connected, which is a hard ceiling on everything. Write both numbers down.
A high margin sends you looking for noise. Pick up the phone and listen for crackle. Try the router in the test socket behind the master socket faceplate with nothing else on the line.
Your pages take too long to load
On shared DSL and cable you are sharing capacity with your neighbours. If the line is quick at breakfast and treacle at eight in the evening, the segment is oversubscribed and that is the provider’s problem rather than yours.
Test across the day and keep the timestamps. That record is what gets a line properly investigated instead of dismissed.
You have forgotten the router password
You get into a router through a browser, at an address like 192.168.0.1 or 192.168.1.1. The address and the login are usually on a sticker underneath.
Tech tip: the router is your default gateway. Type ipconfig at a Windows command prompt or ifconfig in a Mac terminal and it will tell you the address to use.
If somebody has changed the password and nobody remembers it, the reset pinhole on the back returns the router to factory settings. Most ISP routers keep your broadband credentials through a reset and revert the login to what is printed on the case. Retail routers come back completely blank, and the factory login for those is in our directory.
One thing worth knowing before you press it: the router password and the Wi-Fi password are two different credentials, and mixing them up accounts for an enormous amount of unnecessary resetting. We explain the difference in Wi-Fi password versus router password.
The internet drops out
Weather does this more often than people expect, usually through water getting into a joint somewhere between you and the cabinet. It can equally be an outage upstream.
Run a continuous ping to something reliable and leave it going for an hour. If it drops at intervals, you have evidence. Ask the provider for a line test and for the DLM history, because a line that has been unstable often gets dropped to a slower, more conservative profile and stays there for days after the fault clears.
The neighbours are on your Wi-Fi
If your wireless is open or running WEP, anyone within range and a bit of knowledge can join. The result is a slower connection for you, and the rather worse possibility of somebody doing something illegal from an address registered in your name, or watching your cameras without your knowledge.
Change the passphrase. WPA2-PSK is still adequate with a long one, but WPA3 is the current standard and most routers sold in the last few years support it. If yours offers WPA2/WPA3 mixed mode, use that: newer devices get the better handshake and the old ones keep working. There is more on which settings genuinely help in Wi-Fi security basics.
No signal in the kitchen, the garden or the shed
Every house has somewhere the wireless gives up. For a permanent fix, run a cable and put a proper access point at the far end. I use Unifi access points and have done for years.
Mesh kit is the easier option and works well, particularly if you can give it a wired backhaul. Plug-in repeaters are the cheap option and generally a disappointment, because they halve the throughput and usually end up repeating a weak signal.
High ping and lag
Find out what is using the bandwidth first. Look at the connected device list in the router and think about what is out there: the satellite box, the television, the CCTV recorder, the speakers, everything with a plug and an update schedule.
Compromised devices matter here too. The Mirai botnet built itself out of exactly this sort of kit, and a recorder quietly participating in a denial of service attack will flatten your upload without ever showing itself.
If lag genuinely matters to you, look at bufferbloat rather than raw speed. A router that buffers badly will show a fine speed test and a terrible experience the moment anything else starts downloading. Smart Queue Management, on a router that supports it, fixes that properly.
Working through it
- Restart the router. Off at the plug, ten seconds, back on. Check the cables are seated while you wait. Give it up to five minutes to reconnect.
- Check which band you are on. Wi-Fi runs on 2.4 GHz and 5 GHz, and many routers advertise both as separate names ending -2G and -5G. The 5 GHz network is much faster close to the router and falls away quickly through walls. The 2.4 GHz network is slower but reaches further. If the signal is weak where you are, 2.4 GHz will often be quicker despite the lower link rate.
- Change the Wi-Fi channel. Wireless cameras, speakers and every neighbour in the street are competing for the same 2.4 GHz space, and only channels 1, 6 and 11 avoid overlapping each other. Pick whichever is quietest.
- Go wired. For anything that matters, a cable removes an entire category of problem. If you are short of ports, adding a switch costs about twenty pounds.
- Reset the router. The hardware pinhole returns it to factory defaults and clears settings that have gone bad. You will be reconfiguring the wireless afterwards, so treat it as a real step rather than a first guess.
- Update the firmware. Check the manufacturer’s support page for your exact model number. Updates fix real performance and security bugs, and older routers in particular benefit. Some check automatically, some want a file uploading by hand.
- Then call the provider. With your sync rate, your SNR margin and a set of timed wired results, that conversation goes very differently.
Before you phone them
Most providers now want faults reported through their app or website, and you will usually get further there than on the phone. Have the following ready either way.
- Your account number.
- The sync rate and SNR margin from the router’s status page.
- Wired speed test results with the times they were taken.
- Whether the fault follows a pattern, and what you have already tried.
Ask explicitly for a line test and for your DLM profile to be checked. If the fault has persisted, ask what your minimum guaranteed speed was at the point of sale, because the UK broadband code gives you the right to leave without penalty if they cannot bring the line up to it within the agreed window.
Common questions
How often should I restart my router?
You should not have to. If a weekly restart is the only thing keeping it working, the router is failing and needs replacing.
What SNR margin should I have?
Around 6 dB on a stable DSL or FTTC line. Much higher usually means the line has detected noise and reduced your speed to compensate.
Will resetting my router fix a slow connection?
Only if the cause is a bad configuration. A noisy line or a congested segment will be exactly as bad afterwards, and you will have to set the network up again.
Is 5 GHz always faster than 2.4 GHz?
Near the router, yes. Further away, no. A weak 5 GHz signal spends most of its time retransmitting and can end up slower than 2.4 GHz in the same spot.
How do I know if the problem is my router or my line?
Test with a cable. If the wired result matches your package, the line is fine and the problem is inside the house.
