Privet,
ISP -> Linux -> LocalNet.
 Izpolzvam maskarading. Iskam da davam dostyp do Linux-a samo
 na opredeleni IP-ta, no taka 4e te da sa asociirani s MAC
 adresite. Molia pomognete! S iptables li stava tova? A kak
 da im vijdam MAC adresite? Za sega gi gledam samo pod
Windows s "nbtstat".

Blagodaria!

Koito se zanimava s linux e dobra du6a! :o)

 Znachi poneje ne znam dokyde si se sprawil s
 masquerade-inga. Priemam che si se sprawil i ti paste-wam
samo info-to za MAC match
------------------------------------------------------------
6.4.3.2. MAC match

 The MAC (Ethernet Media Access Control) match can be used to
 match packets based on their MAC source address. As of
 writing this documentation, this match is a little bit
 limited, however, in the future this may be more evolved and
 may be more useful. This match can be used to match packets
on the source MAC address only as previously said.

Note

 Do note that to use this module we explicitly load it with
 the -m mac option. The reason that I am saying this is that
 a lot of people wonder if it should not be -m mac-source,
which it should not.

Table 6-9. MAC match options

Match --mac-source

 Example: iptables -A INPUT -m mac --mac-source
00:00:00:00:00:01

 Explanation: This match is used to match packets based on
 their MAC source address. The MAC address specified must be
 in the form XX:XX:XX:XX:XX:XX, else it will not be legal.
 The match may be reversed with an ! sign and would look like
 --mac-source ! 00:00:00:00:00:01. This would in other words
 reverse the meaning of the match, so that all packets except
 packets from this MAC address would be matched. Note that
 since MAC addresses are only used on Ethernet type networks,
 this match will only be possible to use for Ethernet
 interfaces. The MAC match is only valid in the PREROUTING,
FORWARD and INPUT chains and nowhere else.
------------------------------------------------------------
  P.S. M/u drugoto ako si sys statichno IP te sywetwam wmesto
MASQUERADE da izpolzwash SNAT

 A pyk za gledaneto na MAC-ovete na drugite, dokato PC-tata
im sa pusnati nai lesno:
ping $IP
arp -n | grep $IP
i ste vidish MAC-a mu

 mojesh da si reshish si4kite problemi kato pusnesh edno
 DHCPD neka vsi4ki mashini ot mrejata da si zimat IP-tata i
drugitenastroiki ot nego  
piske s iptables:
 iptables -A INPUT -m mac --mac-source ! xx:xx:xx:xx:xx:xx -j
DROP

tva se seki mac adres koito imash v DHCPD-to 

mdaaa, obache ima edin problem.
 Znachi az sum v tozi LAN i ne se predpolaga da poluchavam
internet, demek ne sum si platil primerno :)
 obache sum tarikat i si pravia edna tablichka  na list
 hartia: IP - MAC na userite, koito sa v LAN-a, po-tochno
 interesuvat me samo tezi, deto sa si platili i poluchavat
 internet. Sled tova izdebvam koga niakoe ot tezi pc-ta ne e
 vklucheno. I togava s komandata ifconfig si zadavam negovoto
 IP i MAC :))) Dokolkoto se seshtam, zavisi ot vida na NIC-a,
 poniakoga ne stava, no primerno pri 3com NIC niama problemi.

 E neka togava niakoi da mi ogranichi dostupa po IP/MAC ako
moje :)