how to set a subnet mask on home network

[pedro.smith4444]

Id like to set a subnet mask so i can limit my network to 6 devices.
Im kind of paranoid somebody might be trying to get on my wifi.
How do i do it?
Edit:Btw i posted a screenshot but its not showing up. Im using an at&t router.

 

[kanewolf]

This netmask reference page -- http://www.unixwiz.net/techtips/netmask-ref.html shows what you want.

Using WPA2 with a strong password is a much better implementation.

 

[nigelivey]

Good luck setting a /29 (255.255.255.248) on a domestic router!!