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Re: Need help w/ dhcpd and shared-network option . . .

There are no other routers between the subnets that I know of. 

When we configure our machines statically, all use the same static
route at address X.Y.D.254 (same as static route?) and all use the same
subnet mask of regardless of subnet and has been that way
for nearly 2 years.  (netmasks have always been a bit of voodoo magic
for me anyway (see question below) ack!)  However, our IS dept. told
us to use that subnet mask and additionally delegated us a domain and
the 4 class C subnets for our testing use.  At least I thought they were
class C address blocks:


where the '0' is the network and '255' is the broadcast address.

Also, the dhcp server is also our dns server ( address: X.Y.D.252 )
with a single NIC (eth0) and I can browse the web and ping anything in
or out of our lab by name or address from this machine, so the interface
seems to be working.

Regardless, I added the 'option routers' and 'option broadcast-address'
to each subnet declaration as you suggested and still the same message:

     Warning: subnet X.Y.B.0/22 conflicts with subnet X.Y.A.0/22
     Address range X.Y.B.201 to X.Y.B.254 not on net

If I change the netmask to I get this message:

     No subnet declaration for eth0 (
     Please write a subnet declaration in your dhcpd.conf file for the
     network segment to which interface eth0 is attached.

I then added an additional subnet declaration for <subnet4> inside the
shared-network section but with no range (we don't want any of this
subnet in the dhcp pool) and now it seems to work.  I am most confused. 
Maybe I need to really figure out the netmask thing.  Is the netmask
that is part of the subnet declaration different from the 'option
subnet-mask' statement?

>>> Jeff <jcoppock1@attbi.com> 12/11/01 06:11PM >>>
Jeff Vincent, 2001-Dec-11 17:16 -0700:
> Our test lab has 4 class C address blocks assigned to it that are all
> the same wire (segment?) and we are finally getting around to
> a dhcp server.  We have a Debian-woody (testing) server up, but when
> start it, it says:
> Address range <subnet2>.201 to <subnet2>.254 not on net
> <subnet2>.0/

Have you configured the interface?  This usually occurs because
the interface is not configured or is not up.

Also, I think your netmask is wrong.  A class C is

Also-also, I added two line to one of the subnets below in your
config.  You should add these and duplicate it for each subnet.
Since you are multinetting a single 'wire', it is important to
make sure the broadcasts are unique for each subnet, especially
for the dhcp service.  And, configuring the router is important.

> and then the server exits.  Here is my dhcpd.conf (specific
> ommitted for security reasons):
> shared-network TestLab {
> 	option routers <subnet4>.254;
> 	option ntp-servers <subnet4>.252 , <subnet4>.253;
> 	option domain-name-servers <subnet4>.252 , <subnet4>.253;
> 	option domain-name "<mydomain>";
> 	subnet <subnet1>.0 netmask {
 		range dynamic-bootp <subnet1>.201 <subnet1>.254;
		option broadcast <subnet1>.255;
		option router <subnet1>.1;
> 		}
> 	subnet <subnet2>.0 netmask {
> 		range <subnet2>.201 <subnet2>.254;
> 		}
> 	subnet <subnet3>.0 netmask {
> 		range <subnet3>.201 <subnet3>.254;
> 		}
> 	}
> We statically allocate addresses 1-200 for <subnet1>, <subnet2>,
> <subnet3> and all addresses in <subnet4>.  We now want to put the
> 54 addresses of the first three subnets (e.g., 201-254) in the dhcp
> pool.  What am I doing wrong?  I can't find (or didn't understand)
> correct use of the shared-network block.  
> I also assume the netmask part of each subnet statement is the same
> netmask we set on each statically allocated machine.
> Thanks for any help.
> Jeff


Jeff Coppock		Systems Engineer
Diggin' Debian		Admin and User

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