dhclient: lease renewal woes

Mr Dash Four mr.dash.four at googlemail.com
Wed Aug 29 12:47:54 UTC 2012


> Correct approach - contact your provider and get them to fix their 
> broken network.
I know, but lets just say that they are a bit "unresponsive" (to put it 
bluntly, they don't give a damn).

>> As it stands though, when the lease renewal comes about, my dhclient 
>> becomes "stuck" and I have to restart it.
>
> What *should* happen is that as the lease expiry time is looming, the 
> client should try contacting the server directly a few times. If that 
> fails, then shortly before the lease expires, it should try 
> broadcasting the request - at which point you should get your answer.
That is indeed what happens (I figured this out when requesting a short 
lease just to see how this is going to end), *but* the lease I am 
normally granted from my provider lasts quite long and the time between 
"renew" and "rebind" is a good couple of days. dhclient only tries the 
broadcast approach when the rebind date/time comes about. That means it 
is "trying" to get answers from the external DHCP server non-stop for a 
couple of days!

Is there a way to force dhclient to stop after x number of tries and use 
the broadcast address instead?

Also, I tried to force the issue by including 255.255.255.255 as the 
dhcp-server-identifier value by issuing "supersede 
dhcp-server-identifier 255.255.255.255;" in my dhclient.conf file, but 
that doesn't work because as soon as my cable modem responds to the 
broadcast (using its private IP address) dhclient ignores it as it 
expects answer, quite rightly, from "255.255.255.255". Using "supersede 
dhcp-server-identifier <cable_modem_private_ip_address>;" doesn't work 
either. Any ideas?


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