Is your WiFi secure.

Someone may be using your WiFi connection, they may well not be doing so
maliciously or even knowingly. Sometimes people can't tell which is
their own connection and they may honestly believe that they are using
their Wi-Fi router rather than yours. The best way to deal with this is
to set up your own security.

The optimal solution is to set up a strong password using WPA and change
it regularly. Once your network is functioning, you can switch off the
SSID broadcast [which prevents it from advertising the name of your
network] so it would effectively disappear as far as your neighbours are
concerned.

Firstly you need to determine the ip address of your
modem/router/gateway by finding the Gateway address [try the bookwork
that came with your modem] and putting that ip in the Address line of
your favorite Internet browser [You may not be able to do this via the
wireless (a security feature) so you may need to connect via an ethernet
cable] The address will be something like 192.168.1.1 or 192.168.2.1 or
10.1.1.1 or 192.138.1.254 etc.

At this point you will need to know the default username and password to
login to your device. Login is usually something like administrator or
admin, with a blank or admin password or just a blank username field
with the word password for the login credentials [try the bookwork that
came with your modem for this too].

After you login to the device look for a tab or link that simply says
"Wireless" or "Wireless Security" where you can select the type of
security [use WPA-PSK as it is the strongest of the encryption methods,
or WPA2 if your computer will support it, it is the optimal security
method] that you would like to use for wireless access by computers
connecting to your network. You will need to add a shared-key, to
protect against an attack, a random passphrase of 8 to 63 printable
ASCII [Letters/numbers/symbols]characters is sufficient.

This key will basically be the PASSWORD to your Network [other
computers on your network will also need to use this same key], so only
people who know it will be able to log on to your network. The name of
your network will still appear for people in range, but they will have
to know your shared-key key.

Anyone now trying to access your network will be asked to log in with
your shared-key key. With them not knowing it your network is secure.