security for my home network

[k_mohsen]

hello

I use DSL modem/hub, "Planet ADE-4400 ", for connecting to internet and share it in my home.
my problem is that:
some friends come to my room, un-plug a network cable and plug his/her network cable and connect and use my internet and network. they can access to shared folders in any PCs.

physical protection may harm our friendship. thus I need another method for protection an level-up our security.

so, my question is:
how can I block them to access my network? physical protection is last way to do.

thanks

[mroilfield]

How about talking to your friends and asking them to stop?

[k_mohsen]

yes, I can ask them to stop,
but
it is better to level up security of my home network.

a day will coming that someone access my network that he/she is not my friend.

[WillLik]

Turn off DHCP, change the IP range to something like 192.168.111.XXX.
Change the gateway (the internal router address) to 192.168.111.222.
Static IP on all your devices.
Use a non admin account on all computers in house so IP can't be seen by a passerby.

I know there's more, but without knowing the device that will probably stop it.

[k_mohsen]

when i turn off (or disable) DHCP server, i can not change IP range 

[jason2074]

they can access to shared folders in any PCs.

Turn off your network sharing and discovery.  http://www.lytebyte.com/2007/02/21/how-to-share-one-internet-connection-with-another-computer-using-vista/

[The_Valkyrie]

hello

I use DSL modem/hub, "Planet ADE-4400 ", for connecting to internet and share it in my home.
my problem is that:
some friends come to my room, un-plug a network cable and plug his/her network cable and connect and use my internet and network. they can access to shared folders in any PCs.

physical protection may harm our friendship. thus I need another method for protection an level-up our security.

so, my question is:
how can I block them to access my network? physical protection is last way to do.

thanks

Login to the router and use MAC filtering and the ports will be shutdown not letting them access anything