I'm trying to restrict my dhcp server to only allow known machines by their mac addresses. I'm using dhcpd (ISC). My question is, when I put an entry for each client I want to allow does the name after host have to be the accual hostname of the client computer, or is it just a name that the dhcpd server uses to refer to each mac address?

It's just the name used internally.
(It can be used to populate a dns structure later, but that's a different programme..)

dhcpd doesn't know about Micro$oft...

thanks for the reply. Now I have another problem, I'm trying to restrict dhcpd so it only gives out ips to known computers (by mac address). here is my dhcpd.conf file:

subnet 134.84.86.0 netmask 255.255.255.0 {
# range 134.84.86.200 134.84.86.239;
option routers 134.84.86.254;

# pool{
option domain-name "stat.umn.edu";
option domain-name-servers 128.101.101.101;
range 134.84.86.200 134.84.86.239;

default-lease-time 600;
max-lease-time 7200;
# }
}

ddns-update-style none;
deny unknown clients;

authoritative;
log-facility local7;

host lab1 { hardware ethernet xx:xx:xx:xx:xx:xx; }
host antler { hardware ethernet xx:xx:xx:xx:xx:xx; }


when I try to start dhcpd it complains about the line "deny unknown clients". I tried moving that inside (and uncommenting) the pool and putting it before the subnet but nothing seems to work. Does anyone have any ideas?

Yes, move the line ¨deny unknown clients;" inside the pool....

BUT you are forgetting a } sign! You have the one that ends your pool declaration, but you need one more to end your subnet declaration...

You could always allow the mac addresses to your port 67/68 with iptables. and deny all others. There is an option in iptables to filter by mac address.

iptables -A INPUT -p tcp --dport 67:68 -m mac --mac-source 00:60:08:91:CC:B7 -j ACCEPT
iptables -A INPUT -p tcp --dport 67:68 -j DROP

of course list all wanted mac addresses before the -j DROP