Expired lease not renewing on GREEN


Been running IPFire for many years and this is a new one for me :

So I have two PC’s this morning that would not connect to the network - both are assigned dynamic ip’s via DHCP. So after some investigation i checked the DHCP list on the IPFire GUI and saw that both had expired and were now listed at the bottom of the page ( along with all the others that have expired since God was a boy, but thats another issue :slight_smile: ) with the ‘Lease Expires’ field struck out.

The only way i could get them to work was to ‘Add’ them and assign fixed IP’s.

The DHCP server is working because i added a USB Ethernet adaptor too one of the pc’s and it got an IP straight away - which leads me to the conclusion that the DHCP server is ignoring requests from the original MAC’s on the network cards.

Any idea why this would be the case and why they would not auto renew ? what log files should i check ?

Any help appreciated, because i’ve a feeling i’m going to get a lot of these over the next days and weeks if I can’t resolve the why of the problem.


Hi @uncle_numpty

I would have a search through the logs, looking for all dhcp messages with the ip address that was used for either of those two pc’s.

Normally there will be regular requests for lease renewal from 50% of the lease time onwards so if the leases have expired it means there should be quite a lot of messages in the logs about why the lease was not renewed for those requests. Normally the only reason a lease expires is that the pc has not been connected to the network for longer than 50% of the lease time.

Even if the lease has expired, if you connect the pc back to the network you should get a new lease, as long as there are enough available free leases in the dhcp range.

I would also look in the logs to see the messages related to why those mac addresses are not being given a dynamic ip address.

Well after much reading of log files and tinkering with network card settings etc i think i have nailed it down.

It appears to be a faulty netgear 24 port switch.

It’s strange in that allows traffic for existing leases and fixed ip’s that have been used before, but will not allow new lease or new ip traffic from an existing mac.

Oh well, live and learn I suppose.

As an aside is there a way to manualy restart the dhcp server ?


If you press the save button at the end of the dhcp box on the dhcp configuration wui page then this will restart the dhcp server for you.

If you are unable to access the wui page and need to restart from the command line then run

/etc/init.d/dhcp restart

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