how to reject connections which come from unknown mac address?

Winanjaya · 04-01-2009, 04:43 AM

Dear All,

I have a file (list_macs) that contains list of mac addresses, how to reject connections which come from unknown mac address?

please help

thanks & regards
Winanjaya

datopdog · 04-01-2009, 04:56 AM

use iptables for that.

win32sux · 04-01-2009, 05:07 AM

Assuming that list_macs contains one MAC address per line (and nothing else), here's an example:

Code:

MAC_LIST=`cat /etc/list_macs`
for i in $MAC_LIST; do
  iptables -A INPUT -i eth0 -m mac --mac-source $i -j ACCEPT
done
iptables -A INPUT -i eth0 -j REJECT

Keep in mind MACs only work inside Ethernet LANs.

Winanjaya · 04-01-2009, 08:57 PM

Hi..
but how to store it into /etc/sysconfig/iptables ?

please advise

thanks & regards
Winanjaya

win32sux · 04-02-2009, 05:48 AM

Quote:

Originally Posted by Winanjaya

but how to store it into /etc/sysconfig/iptables ?

If you're on a Red Hat-based distro, use:

Code:

service iptables save

Otherwise, use:

Code:

iptables-save > /etc/sysconfig/iptables

Winanjaya · 04-05-2009, 01:46 AM

Can I use "deny unknown-clients" options in /etc/dhcpd.conf for this? .. I meant I don;t want my dhcp server give IP to unknown clients

deny unknown-clients;
option domain-name-servers 172.16.1.3;
default-lease-time 600;
max-lease-time 7200;

...
...
...

host appio-wireless {
hardware ethernet 00:90:4B:6D:97:59 ;
}
host appio-wired {
hardware ethernet 00:90:3D:93:AD:3E ;
}

please help

thanks & regards
Winanjaya

win32sux · 04-05-2009, 09:40 AM

If you're using ISC DHCP, iptables wouldn't work anyways since ISC DHCP uses a RAW socket. At least, that's how it worked last time I used ISC DHCP. Someone please correct me if things have changed. And yes, it's very common to specify in dhcpd.conf the MACs you wish to provide service to. Keep in mind that MACs are easily sniffed/spoofed, though.