Re: Finishing deprecation of isc-dhcp-client in ifupdown*
On Tue, 4 Nov 2025, Daniel Gröber wrote:
>It falls on you to keep up with system changes then. Hope you're an avid
>NEWS reader :-).
I am.
>Thanks for the hint on which pseudoheader to use!
More help on <debian-init-diversity@chiark.greenend.org.uk> or,
if needed, #debian-init on OFTC.
>anyhow. My preferred solution is porting the fixes to Trixie too, I'm just
>not sure whether the needed changes are "small" enough for a stable update
>at this point :D.
That’s why one can ask the SRM for pre-approval.
>To get there without hacks or re-architecting ifupdown I see a need to
>transition such systems to having `inet6 auto` lines in /e/n/interfaces so
>that ifupdown can come in and decide to launch the DHCPv6 client.
But I want to specifically NOT use a DHCPv6 client, only rtsol.
>Hmm. I think I know whats going on but can you post output for:
>
> $ ps fax | grep dhcpcd # to see which instance types are active
> $ sysctl net.ipv6.conf | grep -E 'accept_ra |autoconf'
tg@tgb1:~ $ ps fax | grep dhcpcd
3088 ? S 0:00 dhcpcd: [manager] [ip4] [ip6]
3089 ? S 0:00 \_ dhcpcd: [privileged proxy]
3163 ? S 0:00 | \_ dhcpcd: [BPF ARP] wlan0 192.168.0.208
3090 ? S 0:00 \_ dhcpcd: [network proxy]
3091 ? S 0:00 \_ dhcpcd: [control proxy]
15069 pts/4 S+ 0:00 \_ grep dhcpcd
tg@tgb1:~ $ sysctl net.ipv6.conf | grep -E 'accept_ra |autoconf'
E: /usr/bin/mksh: sysctl: inaccessible or not found
1|tg@tgb1:~ $ cat /proc/sys/net/ipv6/conf/wlan0/accept_ra
0
tg@tgb1:~ $ cat /proc/sys/net/ipv6/conf/wlan0/autoconf
0
This is from the system now running your code.
On my bullseye systems, which behave as expected, both are 1.
>I've added more hacks to make this work. See
>https://salsa.debian.org/debian/ifupdown/-/merge_requests/28/diffs?commit_id=acc9455eef698b4d51f08c3dfa87e31bdcc1147e
>
>To test it you have to either revert to ifupdown=0.8.44 before upgrading or
>touch /run/network/dhcpcd-inet6-stanza-hack.needed to get the equivalent
>behaviour. LMK how that works out on your machine.
I can pile on the extra commits and rebuild, but I fail to see
how something in /run would persist across reboots…
>I am still hoping we can show upstream the right path here, but that's an
>ongoing effort everyone's welcome to help with on the upstream issue
>tracker :-).
I’m overwhelmed by the stuff already under my wings…
>here. The only case where things get tricky is inet6 auto with dhcp=1 but I
>don't think that's what you're thinking about?
I’m… not in enough context to answer that, either.
We’ll see if the latest iteration helps…
bye,
//Thorsten
--
Thorsten Glaser
Linux / Unix Developer
Tel.: +49 160 91168501
E-Mail: tglaser@b1-systems.de
B1 Systems GmbH
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