From time to time it can be necessary to reboot your router.  If your internet connection drops out or speeds are sluggish, it's worth resetting it, or restarting it, to see if it fixes the problem.

Your router might have a 'reset' button, but be careful as this may wipe its settings, including your broadband username and login details. If you just want to restart your router, look for a power button. If there isn't one, simply turn off the switch at the mains socket for 10 seconds and then turn it back on.

This technique is known as a 'soft reset'.

How do I factory reset my router?

If you need to wipe all the settings - maybe because you've forgotten the admin password you set - then you'll need to find the user manual which will explain which button to press and how long to hold it for. 

Most routers have a similar hard reset procedure which involved using a pen or a pin to press a tiny, recessed button for 10 seconds or so until the lights flash and it reboots. Again, this may vary depending on the manufacturer, but most manuals are available online if you search for the exact make and model.

A hard reset is your only recourse if you have changed (and then forgotten) the default admin password that's used to gain access to the router's settings pages. Without that password you're unlikely to be able to change any settings such as the Wi-Fi password or network name.

When the router reboots, it should be just as it arrived in the box and will probably require some configuration such as your ISP username and password.

Typically, routers supplied by your ISP (such as BT, Virgin, Sky & TalkTalk) use a generic login so should reconnect to the internet without your intervention.

Is my router infected with malware?

You’ve got to have your wits about you these days: scammers and hackers are everywhere. From the patently obvious email and Facebook scams to the invisible keyloggers and fake websites that steal your passwords and identities, it’s almost as if you can’t escape them. Even your router is hackable.

Strictly speaking, it's very unlikely your router has been hacked. What typically happens is that cyber criminals use the known default username and password to change your router’s settings – usually the DNS (Domain Name Servers). The router could then redirect your web browser to fake versions of websites. Since they look the same as sites you already know, you type in your username and password and hand your login straight to the hackers.

Fortunately, most modern routers have individual usernames and passwords which prevents the problem. There's a new generation of 'security routers' which replace or run alongside your existing router and protect all connected devices - including thermostats and other IoT gagets - from hackers. One such product is the Bitdefender Box 2, which includes parental controls and a year's subscription to Bitdefender Total Security on top.

Bitdefender Box

But you should still make it a habit to check in your browser that any website is genuine, especially if it’s your bank or any other financial institution. Such websites have https:// at the start of their address and your browser should also a padlock symbol. If you want to double-check, you can make sure your router is using the correct DNS.

How to check your router’s DNS servers

You will need to log in to your router’s settings, which is accessed via a web browser. Here’s our guide on logging in even if you don’t know its IP address, username or password.

Every router is different, but you should check its menus for DNS servers. They are usually in the WAN, Broadband or Internet connection menu.

In most cases, it should be set to “Automatically obtain DNS server settings from ISP”. This means it will use the server addresses from your internet provider: BT, TalkTalk, Sky, Virgin or other supplier.

If it’s set to “Use the following” and numbers are present, check these using Google to find out if they are within the ranges allocated by your ISP. If they don’t match up, be suspicious. Note that you can’t simply enter the numbers into Google as it will try to open it as a website. Instead, include the name of your ISP, for example: “BT DNS 217.32.171.21”.

How to check if your router is infected with malware, and how to fix it if it is.

Either enter the correct DNS servers (there are usually two different addresses, a primary and a secondary, such as 62.6.40.178 and 62.6.40.162) or change the setting to automatically obtain the addresses, save the changes and reboot your router. (It should tell you it needs to reboot, and either do it automatically or ask you to click ok.)

How to rid your router of malware

We’ve already explained how to check your router is using the correct DNS settings, but if after a reboot or unplugging from the mains for a minute, your router is still reporting spurious DNS servers, it could be infected with malware.

The only way to remove this is to install the latest firmware from your router manufacturer. As before, every router is different, so you’ll have to look through its settings menus to find the option to upgrade the firmware.

And if your router is using the wrong DNS servers, it’s best to download the latest firmware using a different router, which probably means doing it at work or a friend’s house, unless you have an old router lying around.

Head to your router manufacturer’s website, look for a Support section and then search for your particular router model. This is always printed on a sticker somewhere on the router.

You’ll have to download the firmware to your hard disk or a USB stick. Then, back in the router’s menus, look for an Upgrade firmware option and direct the router to where your firmware file is saved. It might be possible to plug in a USB stick containing the firmware directly to the USB port on your router, but you’ll still need a laptop or PC to start the update process.

If your router won’t accept the file because of the malware, it might – in extreme cases – be necessary to replace the router with a new one.