Expanding DHCP pool [Solved]

mawhii · 2009-09-29 20:48:14

Currently i've got a dhcpd server setup I inherited with a range of 192.168.0.1 -> 192.168.0.254 (mask 255.255.255.0) and it's close to filling up.

I'm looking to expand that to 192.168.0.1 -> 192.168.3.254 (mask is 255.255.252.0 i think?) to cope with the expansion. I've got the dhcpd server to assign the addresses, but it seems something on 192.168.2.x can't see a 192.168.0.x computer.. I'm guessing this is an issue with the subnet mask. What are my options on going around this so that each block can see the other?

I set the bcast on the new setup to 192.168.3.255 which is the settings i've calc'd, aswell as the mask on the iface and dhcpd.conf to 255.255.252.0.

Is there anything else I need to do? Or do I just need a basic primer on subnets? The dhcpd server is setup to use the IP 192.168.0.15.

Thanks!

Last edited by mawhii (2009-09-30 01:18:58)

crankyadmin · 2009-09-29 21:02:49

May be something as silly as getting the machine in question to renew its DHCP lease... there is not much more to do. As long as all the machine are sitting on the same subnet in your case /22 there isn't a hole lot more todo.

mawhii · 2009-09-29 21:18:47

I don't think that's it, after the system with 2.x gets it's IP, it can't even see our DNS server (same ip as dhcpd).

I'll give it a shot with a few machines and updated ips though.

fukawi2 · 2009-09-29 22:30:10

mawhii wrote:

I don't think that's it, after the system with 2.x gets it's IP, it can't even see our DNS server (same ip as dhcpd).

apologies for asking a stupid question, and again if you've already answered it in your post and I missed it, but have you updated the IP config on the DHCP/DNS server to the new subnet mask?

Also, install tcpdump on the DHCP/DNS server and try running something along the lines of:

tcpdump -lnn -i ethX arp and host X.X.X.X and host Y.Y.Y.Y

ethX = LAN interface
X.X.X.X = DHCP server IP (eg, 192.168.0.1)
Y.Y.Y.Y = client IP (eg, 192.168.3.100)

mawhii · 2009-09-30 01:18:41

Aha! got it! cranky was right. The Pc I was connecting to still had the 255.255.255.0 subnet.

As for DNS.. turns out it was only setup to accept 192.168.0.0/24!

Switched over now and everythings smooth

crankyadmin · 2009-09-30 09:18:09

mawhii wrote:

Aha! got it! cranky was right. The Pc I was connecting to still had the 255.255.255.0 subnet.
As for DNS.. turns out it was only setup to accept 192.168.0.0/24!
Switched over now and everythings smooth

FTW!

Arch Linux

#1 2009-09-29 20:48:14

Expanding DHCP pool [Solved]

#2 2009-09-29 21:02:49

Re: Expanding DHCP pool [Solved]

#3 2009-09-29 21:18:47

Re: Expanding DHCP pool [Solved]

#4 2009-09-29 22:30:10

Re: Expanding DHCP pool [Solved]

#5 2009-09-30 01:18:41

Re: Expanding DHCP pool [Solved]

#6 2009-09-30 09:18:09

Re: Expanding DHCP pool [Solved]

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