I'm using wireshark on lubuntu to sniff on my wifi(WPA-PSK encrypted). No frames from other ip's are shown. Tried ifconfig wlan0 promisc But without result.
Not all wifi adapters allow promiscuous mode, you may have one. And what's more, libpcap can't do it natively. WireShark's wiki has some tips on getting it running. Specifically, you'll probably need the aircrack-ng packages and use the airmon-ng script included in it.