Yeah, useful info.
Some info about my router:
Firmware: 3.9.7 Build 090821 Rel.58159n
Hardware: WR841N v5 00000000
Perhaps my router is old and have alot of flaws.
But I got a new question.
How about "satellite internet" ? (In this case, I figured out, that person always connects extra device (because of noise I hear), perhaps it is adapter.)
Can satellite router( or receiver ) bypass my router, im sure it requires WAN port, etc...?
Because If I Unplug my router and 'black anthena wire' ( which is connected to device named 'Power Active LAN POE') , that person goes mad.