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Old 05-08-2015, 09:23 AM   #1
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Registered: May 2015
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Hi guys,

New member and first time poster. I was wondering if anyone can help me configuring a dhcp relay agent. I have tried everything and Googled high and low before I came here, so I tried my best to figure it out myself.

So short story, I am a total newbie as I only ever worked on Windows Server.

My configuration is very simple and consists of client <--> (eth0)Router(eth1) <--> Server. Using Ubuntu 14.04 LTS.

auto eth0
iface eth0 inet static

auto eth1
iface eth1 inet static




auto eth0
iface eth0 inet static

ddns-update-style none;
#option domain-name "";
#option domain-name-servers,;
default-lease-time 600;
max-lease-time 7200;
log-facility local7;

option subnet-mask;
option broadcast-address;
option routers;

subnet netmask {

subnet netmask {

Now the problem. I ensured the dhcp-relay is running on the router

sudo service isc-dhcp-relay status
isc-dhcp-relay start/running, process 4107


But when I try to obtain an IP address from the client - Nothing!

But, if I issue this command on the router dhcrelay -d

Internet Systems Consortium DHCP Relay Agent 4.2.4
Copyright 2004-2012 Internet Systems Consortium.
All rights reserved.
For info, please visit
Listening on LPF/eth1/00:0c:29:32:ca:5d
Sending on LPF/eth1/00:0c:29:32:ca:5d
Listening on LPF/eth0/00:0c:29:32:ca:53
Sending on LPF/eth0/00:0c:29:32:ca:53
Sending on Socket/fallback
Forwarded BOOTREQUEST for 00:0c:29:37:88:c5 to
Forwarded BOOTREPLY for 00:0c:29:37:88:c5 to
Forwarded BOOTREPLY for 00:0c:29:37:88:c5 to

Bang, right away a glorious IP address. Now if I exit out of the terminal, again the client will not obtain an IP address. It's only when I run dhcrelay -d and let the terminal window sit there will the dhcp-relay work properly.

I am seriously confused, what am I doing wrong and why can't I run dhcp relay as a service?

Last edited by gigz021; 05-08-2015 at 09:24 AM.
Old 05-08-2015, 10:28 AM   #2
Senior Member
Registered: Dec 2003
Location: The Key Stone State
Distribution: CentOS Sabayon and now Gentoo
Posts: 1,249
Blog Entries: 3

Rep: Reputation: 194Reputation: 194
Your network statements in your config files are wrong.

Code:   network = network =
The second interface the network you have configured is outside the assigned ip address.
Not saying this is the problem but it could be.
And the network statement is deprecated.


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