Server Fault is a question and answer site for system and network administrators. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I took down my DHCP server to change some stuff, and after bringing it back up (down for 15 mins or so), I noticed that four other Ubuntu 12.04 servers set to use DHCP were unreachable. Running ifconfig on them returned just lo, so the eth0 and eth1 had been disabled.

I'm assuming the DHCP server missing caused them to shutdown the interface? Not sure why, they've been assigned static dhcp ips in dnsmasq. How do I set Ubuntu to never give up trying for a dhcp address on a connected interface?


share|improve this question

Yes of course, lease time is 1h by default, so if you want to avoid this, just make the lease e.g. 1 week.

On client, in /etc/dhcp/dhclient.conf set send dhcp-lease-time 604800.

share|improve this answer
wait, isn't lease time set by the server? the dnsmasq range was static, so I figured the lease time was infinite then. – Cyclone Jul 20 '12 at 0:45
Nope, on this Ubuntu the lease time is on the client. Static range, what do you mean by this? There is no infinite lease. The IPs are never dynamic (it's not a dialup connection). – Andrew Smith Jul 20 '12 at 10:38
In dnsmasq you can explicitly set aside an IP range as 'static', which means dnsmasq will only issue IPs in that range if you have explicitly assigned it to a particular hostname/mac-address/clientid. – Cyclone Jul 20 '12 at 15:54

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.