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Old 06-25-2010, 05:31 PM   #1
Registered: Jun 2010
Distribution: Debian, Ubuntu, Win
Posts: 141

Rep: Reputation: 16
DHCP offers not being limiting to specified vlan interface on debian.

Hi All,

I have configured dhcp3-server on my debian box and I'm wanting to offer dhcp on one of the vlan interfaces. The dhcp is functioning but when I test applying it to a different vlan, the original PC can still get an IP.

For example:
eth1 has vlan100 and vlan200. Our managed switch has the ports configured such the pc1 is on vlan100 and pc2 is on vlan2. This works fine and I can inter-route between vlans with static IPs.

Our dhcp config is currently set as:

ping-check true;
ddns-update-style none;
default-lease-time 21600;
max-lease-time 86400;

subnet netmask {
option domain-name-servers;
option routers;
option broadcast-address;
option subnet-mask;

I've researched this issue but can't find a definative answer?

Old 06-26-2010, 01:48 AM   #2
Registered: Jun 2001
Location: UK
Distribution: Gentoo, RHEL, Fedora, Centos
Posts: 43,417

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well your config only has one subnet, are you running the same subnet on two vlan's?? I really hope not. As for what else is wrong, you can see that the INTERFACES line looks totally diffferent from the other lines doesn't it? It does not belong in that file at all, infact I'd have thought that it'd stop DHCPD loading at all as the symtax is totally illegal there. I assume it goes in /etc/sysconfig/dhpcd or similar, something that will be directly turned into a command line argument, not a config inside the program.
Old 06-27-2010, 02:12 AM   #3
Registered: Jun 2010
Distribution: Debian, Ubuntu, Win
Posts: 141

Original Poster
Rep: Reputation: 16
Hi Chris,

Thanks for your reply.

I've now added the additional subnets for all of the applicable network interfaces and just by this it is now doing what it should be doing.

I found the 'INTERFACES' part in another forum thread and thought I'd try it. I too find it strange that it allowed the daemon to start properly and it didn't throw up any errors in the syslog. However I've now removed it anyway as it had (obviously) no effect.

Thanks again for your help.


debian, dhcp, vlan

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