There are two very different reasons behind this search, and each needs a different route.
The first: an unfamiliar device is piggybacking and you want it gone. The second: the device belongs to someone in the house, but you want to limit when it is used.
For the first, blocking per device is not actually the best answer, and the reason is worth knowing before you spend time in the wrong menu.
Seeing who is currently connected
Open the router's settings page at its IP address, usually 192.168.1.1. How to find that address is explained in the guide to local IPs and DHCP.
Look for a menu called Client List, Attached Devices, DHCP Client, or Network Map. It lists the devices along with their MAC and IP addresses.
The trouble is that the list rarely gives clear names. How to work out which is which:
- Switch Wi-Fi off on one device you recognise.
- Reload the list after a minute or two.
- The entry that vanished is that device. Note its MAC address.
- Repeat until every household device is identified.
Whatever entries remain unidentified once every household device is accounted for are the ones worth suspecting. Other symptoms to read are covered in the guide to spotting a compromised Wi-Fi network. Where you stand as the network owner if someone really is piggybacking is covered in the guide to using a neighbour's Wi-Fi without permission.
Do not jump to conclusions. An ordinary house has far more devices than its residents imagine, the television, a games console, cameras, smart plugs, even the washing machine. A long list does not necessarily mean anyone is piggybacking.
Three ways to block, and when each fits
| Method | Effective for | Lasts? |
|---|---|---|
| Blocking by MAC address | Household devices you recognise | No, if the address is randomised |
| Access scheduling | Limiting hours of use | Yes, for permanent devices |
| Changing the password | Removing everyone uninvited | Yes |
Blocking through the device list
Once the MAC address is noted, look for the filtering menu. The name differs by brand:
| Brand | Menu path |
|---|---|
| TP-Link | Advanced → Security → Access Control → Blacklist |
| ZTE | Network → WLAN → WLAN Access Control |
| Huawei | WLAN → WLAN MAC Filter |
| Asus | Network Map → Client → Block, or Wireless MAC Filter |
| Tenda | Advanced → Client Filter |
| D-Link | Features → MAC Filter |
There are generally two modes. Blacklist blocks the addresses you list and allows the rest, this is what is normally used. Whitelist is the opposite: only listed addresses may join. Whitelist is stricter, but every guest and every new device has to be registered manually first.
Why MAC blocking often does not last
This part is rarely mentioned in other guides, yet it is decisive.
For several years now, Android and iOS have used a randomised MAC address, different for each network, as a privacy protection so users' movements cannot easily be tracked between locations.
The consequence is simple: the moment someone forgets your network and reconnects, their phone gets a new address. Your block list still holds the old one, and that device walks back in as an entirely unfamiliar guest.
MAC addresses can also be changed manually on a laptop without special tools. So MAC filtering is genuinely useful, but as a household management setting, not as a barrier against someone determined to get in.
The steps that actually settle it
If what you face is a piggybacker, the following order is far more effective than blocking one device at a time.
Change the Wi-Fi password
This single step cuts off every device you have not given the new password to, however many there are and whatever their MAC addresses. The steps are in the guide to changing your Wi-Fi password.
Switch on the guest network
So you never need to hand out the main password again. Guests use a separate network whose password can be changed at any time without disturbing household devices. How to do it is in the guide to separating a guest network.
Make sure the encryption is WPA2 or WPA3
A network using WEP or no password at all can be entered without knowing anything. Blocking devices on a network like that achieves nothing.
Turn off WPS
That quick-pairing button has a long-known weakness that lets people in without the password. More on this in the guide to securing a home router.
Limiting rather than blocking
For household devices, cutting the connection entirely is often excessive. Two gentler alternatives:
- Access scheduling. Found in the parental controls menu on most routers. A given device can only connect during the hours you set.
- Speed limits. Through the QoS or bandwidth control menu, one device is given an upper limit so it cannot consume all the capacity while downloading. This often settles the complaint of "the internet is slow whenever so-and-so is home" without cutting anyone off.
If the complaint really is slowness, first check whether the cause is genuinely the number of users. Often it is not, discussed in the guide to fixing slow Wi-Fi.
For a business, do not do this manually
Blocking one device at a time will never keep up in a cafe or clinic where the visitors change daily. What is used there is a portal with time-limited sessions and per-device speed limits, so control runs itself and there is nothing to block.
Capacity calculations and the arrangement are discussed in the guide to venue Wi-Fi capacity.
A closing note: everything above applies to networks you own or manage yourself. Changing settings on someone else's network is an entirely different matter, and not what is discussed here.
Frequently asked questions
Does a blocked person know they have been blocked?
There is no notification of any kind. From their side, the device fails to connect or connects with no internet, much like an ordinary fault. Some routers give a different message, but generally it is indistinguishable from a network having trouble.
Why does a blocked device reappear?
Because modern phones use a randomised MAC address for each network. Once the user forgets the network and reconnects, their phone gets a new address that is not on your block list, and appears as an entirely different device.
Is it better to block by MAC or change the password?
Change the password. MAC blocking closes one address, while changing the password cuts off everyone you have not given the new password to. MAC blocking is useful for household devices you recognise, not for removing a piggybacker.
Can you block only at certain hours?
Yes, through the parental controls or access scheduling menu on most routers. This suits household devices better, limiting a child's tablet during study hours, say, than unfamiliar ones.
