MAC address change

Jan Markus markus.jan at seznam.cz
Thu Nov 24 15:59:50 UTC 2011


Hello,

we have a customer in VLAN 101. For this customer, we have a 10.0.0.0/29 pool. We also offer one 
public IP per customer (with subnet /30). DHCP server v4.1.2 is running on our router.

One day customer wanted public IP for one of his servers with MAC 00:11:22:33:44:55. I added first 
address of this IP subnet to VLAN interface on the router, so:

	# ifconfig vlan101
	vlan101:
		...
		inet 10.0.0.1 netmask 255.255.255.248 ...
	        inet 1.1.1.1 netmask 255.255.255.252...
	        ...

And I put this into dhcpd.conf:

	host customer101public {
	    hardware ethernet 00:11:22:33:44:55;
	    fixed-address 1.1.1.2;
	}
	
	shared-network vlan101 {
	    subnet 10.0.0.0 netmask 255.255.255.248 {
	        range 10.0.0.2 10.0.0.6;
	        option routers 10.0.0.1;
	    }
	
	    subnet 1.1.1.0 netmask 255.255.255.252 {
	        range 1.1.1.2;
	        option routers 1.1.1.1;
	    }
	}

Everything works all right. Now the customer wants to purchase a new server and he wants me to 
remove public IP from his old server, until he will send me MAC address of the new one. So I just 
changed MAC in the "host" declaration, restarted DHCP daemon (even removed leases file).

But the old server is still "getting" the public IP address, or it is "keeping" it. How can I 
specify in the dhcpd.conf, that this IP is no more for him, so he will lease address from the 
10.0.0.0/29 pool?

Thank you very much for your time.
-Jan



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