Free Internet without using up your own data volume? Sounds tempting, but be careful!

Whether in big cities or on vacation beaches - online users are increasingly able to access a free open Wi-Fi network. Sounds great and is incredibly practical - but open Wi-Fi has its pitfalls when it comes to data protection.

Open Wi-Fi: Never use networks without encryption

The German Federal Office for Information Security warns: Stay away from public networks that you can use without a password. In theory, anyone could read what you enter into your cell phone, tablet or notebook.

Always take warning messages seriously

If you see error messages when surfing while using open Wi-Fi, this could be a hacker attack. Typical messages include: "There is a problem with the site's security certificate. It is recommended that you close the website and do not switch to this website". If you see this message, it is best to close the website immediately.

Check virus protection and firewall before use

If you are surfing with your notebook, you should definitely update your firewall - otherwise hackers will have an easy time of it. The selection of virus protection programs for smartphones is currently still quite limited. Therefore, the most important and simplest measure is to always update regularly as soon as a new one is available.

Never choose the same password everywhere

TÜV Süd recommends choosing a different password for all accounts that are used online. Combinations of upper and lower case letters with numbers and special characters are ideal. Different passwords make it more difficult for hackers to gain access to your accounts via the "forgotten password" function.

Only switch on WLAN and Bluetooth when required

If you are outside a secure network and do not need an open WLAN, switch off the function. This way, you don't leave yourself open to attack. Bluetooth should also be switched off to be on the safe side. And: As soon as you leave an open WLAN, delete it from the list so that your cell phone does not automatically dial in when you are in the vicinity.

Do not carry out any banking transactions via the hotspot Online banking or other sensitive transactions should never be carried out in an open WLAN. Experts even advise against simply checking your account balance.