Multicast setup

Chuck Anderson cra at WPI.EDU
Fri Nov 3 16:39:00 UTC 2006


On Fri, Nov 03, 2006 at 09:29:54AM -0600, Cody Holland wrote:
> assigned to the local dhcp server network card. For some reason the dhcp
> server is trying to assign IP's out of the subnet for the local
> interface and getting errors that there are no free leases. The
> following is the dhcp config that I am currently using, any help on this
> would greatly be appreciated.

The server matches subnets based on the giaddr value in the incoming 
DISCOVER packets.  If the giaddr is 0.0.0.0, then the server will 
assign an IP out of the local interface subnet.

> # Server IP Network
> subnet 172.17.101.0 netmask 255.255.255.224 {
>         option routers 172.17.101.1;
>         authoritative;
>         # DHCP Server
>         host DHCPServer {
>                 hardware ethernet 00:30:48:78:5b:c8;
>                 fixed-address 172.17.101.5;
>                 }
>         }

host { } statements are always global semantically, even if they are 
put into other scopes syntactically.  To avoid confusion, it would be 
best to put all host { } statements outside of all other subnets, 
pools, etc.

> # Mesh INF
> subnet 172.16.0.0 netmask 255.255.252.0 {

I would run tcpdump or ethereal (wireshark now) to check the incoming 
packets to be sure the "ip helper" is acting as a proper DHCP Relay 
Agent and is setting giaddr correctly to the router's subnet 
interfaces on the client networks.


More information about the dhcp-users mailing list