What about configuring DHCP to assign IP addresses to known MAC addresses only? I know ISC dhcpd does this and have used it for a couple of clients. It was fairly easy to build a dhcpd.conf from the dhcp log file .. so no real headche with collecting MAC addresses for the initial configuration. But you may still want to match each MAC address to its owner before putting it in the config file.
This still allows the smarter people to pick and choose an unused IP to bypass the DHCP mechanism altogether. There's a cycle-intensive solution: use iptables with MAC-matching for all known MACs. -- Hasnain ----- Original Message ----- From: "Sarbjit Singh Gill" <[EMAIL PROTECTED]> To: "Rick Darsey" <[EMAIL PROTECTED]>; "jon kintner" <[EMAIL PROTECTED]>; <[EMAIL PROTECTED]> Sent: Thursday, December 05, 2002 7:14 AM Subject: RE: Preventing DHCP from allocating IPs > That was one of my options but seems like the Administrators did want to be > bothered every time somebody needed an IP. > > Gill > > -----Original Message----- > From: Rick Darsey [mailto:[EMAIL PROTECTED]] > Sent: Wednesday, December 04, 2002 4:05 AM > To: jon kintner; [EMAIL PROTECTED]; > [EMAIL PROTECTED] > Subject: RE: Preventing DHCP from allocating IPs > > > > I know this sounds like a really bad way of doing this, but it is the only > way I can come up with off the top of my head: > > Turn of DHCP!! Statically assign all addresses in your LAN. If a visitor > wants access to your network, they will have to come to you to obtain the > address, or better yet, create a small DHCP pool that visitors can use, but > limit the size to prevent users you do not want from accessing the network. > The initial setup of the static addresses will take time, but the small DHCP > pool will still allow visitors to plug in when needed. > > Rick > > -----Original Message----- > From: jon kintner [mailto:[EMAIL PROTECTED]] > Sent: Monday, December 02, 2002 1:04 PM > To: [EMAIL PROTECTED]; [EMAIL PROTECTED] > Subject: Re: Preventing DHCP from allocating IPs > > > I know mac addresses can be spoofed pretty easily, but could you setup an > access list or filter that would disallow all mac addresses except for the > ones specified on your network(s)? > The initial setup would probably be tedious, but it's worked fairly well to > keep most unauthorized logins off the network at the college I attend. > > -jon kintner > > ----- Original Message ----- > From: "Sarbjit Singh Gill" <[EMAIL PROTECTED]> > To: <[EMAIL PROTECTED]> > Sent: Monday, December 02, 2002 7:22 AM > Subject: Preventing DHCP from allocating IPs > > > > Greetings all, > > > > How do i prevent a client from getting an IP from my DHCP in an Ethernet > > network. I know i could reserve IPs for all other clients and nobody gets > an > > IP unless reserved earlier, but i have hundreds of clients. I frequently > > have visitors who need to plug in their laptops into the network and i > have > > visitors who are not allowed to plug in their laptops into the network and > > get IPs. I do not want these visitors who are not allowed to access the > > network to get an IP and start accessing internet through my network. > > > > What about in a wireless environment. How do i prevent it in a similar > > capacity. > > > > Kind Regards > > Gill > > > > > >
