Very Computer

by **B. T** » Sat, 07 Aug 1999 04:00:00

Hi.

I am setting up a Linux box to run I.P. Masquerading for other machines
on my LAN. Question is I want to be able to give access to those machines
that
satisfy two prerequisites: The I.P. address the machine has been
assigned must match the mac address of the NIC card. It's probably
some simple switch in the software I'm not aware of, but I neither have been
able to locate
it in the software or in the HOWTOs.

Does anybody know how to do this?

Thanks,
B.T.

by **Juergen Pabe** » Sat, 07 Aug 1999 04:00:00

how are you planing to do that? the mac address is 48bit while ip
addresses are 32bit. even if you'd decide to chop off 16bit, you also
have to consider that all boxes *should* be in the same subnet (meaning:
all mac#s need to be in a very small range, unlikely to happen)

jp

> Hi.

> I am setting up a Linux box to run I.P. Masquerading for other machines
> on my LAN. Question is I want to be able to give access to those machines
> that
> satisfy two prerequisites: The I.P. address the machine has been
> assigned must match the mac address of the NIC card. It's probably
> some simple switch in the software I'm not aware of, but I neither have been
> able to locate
> it in the software or in the HOWTOs.

> Does anybody know how to do this?

> Thanks,
> B.T.

by **B. T** » Sat, 07 Aug 1999 04:00:00

The Internet-enabled T3 network at my college makes sure that the mac
address
of the NIC and the IP address of the computer match before allowing a
student
to access the Internet. At the beginning of the school year, each computer
is assigned
an unique IP address. The server "locks" onto the mac address of the NIC
and checks
to make sure the mac address corresponds to the IP address before allowing
the user to access
the Internet. So, if the user gets a new NIC, he will not be able to access
the Internet because
the mac address of the new NIC is different from the one on record. The
reason for this is that
last year people were using other people's IP address to do bad things. I
am trying to do
the same thing on my private network.

So, I am not trying to match the IP address to the mac address.

B.T.

Quote:> how are you planing to do that? the mac address is 48bit while ip
> addresses are 32bit. even if you'd decide to chop off 16bit, you also
> have to consider that all boxes *should* be in the same subnet (meaning:
> all mac#s need to be in a very small range, unlikely to happen)

> jp

by **Juergen Pabe** » Sun, 08 Aug 1999 04:00:00

ok, as long as we're clear about that....

in the /etc/dhcpd.conf file you can set host options, for more examples
check out

man dhcpd.conf

but in general like this:

host windoof
{
hardware ethernet 00:40:95:33:85:cc;
fixed-address 192.168.1.10;

}

> The Internet-enabled T3 network at my college makes sure that the mac
> address
> of the NIC and the IP address of the computer match before allowing a
> student
> to access the Internet. At the beginning of the school year, each computer
> is assigned
> an unique IP address. The server "locks" onto the mac address of the NIC
> and checks
> to make sure the mac address corresponds to the IP address before allowing
> the user to access
> the Internet. So, if the user gets a new NIC, he will not be able to access
> the Internet because
> the mac address of the new NIC is different from the one on record. The
> reason for this is that
> last year people were using other people's IP address to do bad things. I
> am trying to do
> the same thing on my private network.

> So, I am not trying to match the IP address to the mac address.

> B.T.

> > how are you planing to do that? the mac address is 48bit while ip
> > addresses are 32bit. even if you'd decide to chop off 16bit, you also
> > have to consider that all boxes *should* be in the same subnet (meaning:
> > all mac#s need to be in a very small range, unlikely to happen)

> > jp

by **David G. Mack** » Mon, 09 Aug 1999 04:00:00

Quote:>So, I am not trying to match the IP address to the mac address.

Do a "man arp". What it sounds like you want to do is assign static
arp table entries for the machines on your network, so pay extra
attention to the -s and -f options.

-Dave

Very Computer

IP Masquerading with IP Address and Mac Address Restrictions

IP Masquerading with IP Address and Mac Address Restrictions

IP Masquerading with IP Address and Mac Address Restrictions

IP Masquerading with IP Address and Mac Address Restrictions

IP Masquerading with IP Address and Mac Address Restrictions

IP Masquerading with IP Address and Mac Address Restrictions