Hi Torsten, On Mon, Jul 07, 2025 at 12:45:04PM +0200, Thorsten Glaser wrote: > In contrast to earlier Debian releases with ISC dhcp-client, a “sudo ifup > wlan0” > with DHCP enabled runs the post-up command from /etc/network/interfaces and > returns to the shell (consider “sudo ifup wlan0 && sudo rdate -nv ntpserver”) > before the network interface is ready: rdate tells me no connection to host, > and a few seconds later only it works.
I think what's happening is that dhcpcd's default is to wait for "any IP
address to be assigned" meaning that in a network with IPv6 SLAAC it's
going to return with only a v6 address assigned as that's almost always way
faster than legacy DHCP which may not be what you're expecting.
You can test this yourself by doing the following (replace eth0 obv.):
$ dhcpcd eth0; ip a; ip route; ip -6 route
(Notice how there's no IPv4 address or default route yet)
I'm working on a patch for the dhcpcd<>ifupdown integration that will fix
this.
--Daniel
signature.asc
Description: PGP signature
