dhcpcd-discuss

RE: Problematic Buster dhcpcd lease renewal behavior

bls s

Mon Dec 21 14:33:53 2020

Thanks, Roy. I'll check these out.

-----Original Message-----
From: Roy Marples <roy@xxxxxxxxxxxx> 
Sent: Saturday, December 19, 2020 11:19 PM
To: bls s <bls3427@xxxxxxxxxxx>; dhcpcd-discuss@xxxxxxxxxxxx
Subject: Re: Problematic Buster dhcpcd lease renewal behavior

Hi

On 19/12/2020 22:50, bls s wrote:
> I'm seeing a problematic dhcpcd behavior difference on a Raspberry Pi 
> between Stretch (dhcpcd 6.11-5) and Buster (dhcpcd 8.1.2) when used on the built-in WiFi.
> 
> On my network, once the DHCP lease time is 50% expired, the Buster dhcpcd starts requsting a new DHCP address every minute or so, for what appears to be forever.
> 
> Contrast that with Stretch dhcpcd where the lease was correctly renewed and there were no extraneous DHCP requests.
> 
> For some reason that I can't sort out, Buster dhcpcd thinks that the DHCP server ACK is not good, sends an ICMP destination unreachable packet, and then goes into a state that I've never seen before, eventually getting a lease but shortly thereafter restarts the cycle.
> 
> Both tests were run on the same Pi, against the same isc-dhcp-server 4.4.1-2. (The DHCP lease time is normally 24 hours, and that's where I first saw this, but I set it down to 10 minutes because who has the patience for that?).
> 
> Is there some additional configuration required on either the DHCP server or in dhcpcd to make this work correctly, as it did on Stretch?
> 
> Thanks!

There have been some fixes around this in dhcpcd-8 and a final one today as well which fixed a similar reported issue in dhcpcd-8.1.9 in NetBSD-9.0

Patches from dhcpcd-8 branch of note:
https://roy.marples.name/cgit/dhcpcd.git/commit/?h=dhcpcd-8&id=ecb8f4b14de3ad9e8d0901db43269fd36c972123
https://roy.marples.name/cgit/dhcpcd.git/commit/?h=dhcpcd-8&id=002e7ccc2ade2379d4d5d1e8b9a5f6a3fc448d64

Hopefully these fix it for you.

Roy

References:
Problematic Buster dhcpcd lease renewal behaviorbls s
Re: Problematic Buster dhcpcd lease renewal behaviorRoy Marples
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