ISC-DHCP not providing address

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http://askubuntu.com – I just replaced my old router using server with Ubuntu. Everything's fine except DHCP. When I tried connecting iPhone - it works: http://pastebin.com/NNEeiRLY but unfortunately some of my devices can't get IP from server, e.g. my computer: http://pastebin.com/N6LnsEWC Here's my isc configuration: http://pastebin.com/N5KQnhZV I've also tried running DHCP server as root (because of some permission denied in logs on lease file). What can I do? (HowTos)