Dear Maintainer,

   * What led up to the situation?

Running "ifdown enp1s0f4"

   * What exactly did you do (or not do) that was effective (or
     ineffective)?

N/A

   * What was the outcome of this action?

N/A

   * What outcome did you expect instead?

No error message.


Here is the error I get:

#
Jan 21 04:17:30 ice dhclient[303659]: DHCPRELEASE of 1.1.1.1 on enp1s0f4 to 2.2.2.2 port 67
Jan 21 04:17:30 ice dhclient[303659]: send_packet: Invalid argument
Jan 21 04:17:30 ice dhclient[303659]: dhclient.c:2879: Failed to send 300 byte long packet over fallback interface.
#

I also had started a thread on the ISC dhcp-users mailing list:

https://lists.isc.org/pipermail/dhcp-users/2023-January/022820.html

From what I can tell (I could be wrong) - the logic to make dhclient send a RELEASE is compiled into ifup via inet.defn.

To me it looks like dhclient release happens first, before the "ip link" command shuts down the interface.

Nevertheless I still get this issue.
--- up and down scripts installed:
/etc/network/if-down.d:
total 12
-rwxr-xr-x 1 root root 289 Sep 21 06:40 bind9
-rwxr-xr-x 1 root root 372 May 14  2021 openvpn
-rwxr-xr-x 1 root root 800 Jan  7  2022 postfix

/etc/network/if-post-down.d:
total 4
-rwxr-xr-x 1 root root 1433 Feb  4  2019 vlan
lrwxrwxrwx 1 root root   33 Sep  6  2020 wide-dhcpv6-client -> ../../wide-dhcpv6/dhcp6c-ifupdown

/etc/network/if-pre-up.d:
total 12
-rwxr-xr-x 1 root root  344 Jun 30  2016 ethtool
-rwxr-xr-x 1 root root 4224 Feb 21  2019 vlan

/etc/network/if-up.d:
total 24
-rwxr-xr-x 1 root root  289 Sep 21 06:40 bind9
-rwxr-xr-x 1 root root 1685 Jun 30  2016 ethtool
-rwxr-xr-x 1 root root  677 Feb  4  2019 ip
-rwxr-xr-x 1 root root  385 May 14  2021 openvpn
-rwxr-xr-x 1 root root 1183 Jan  7  2022 postfix
-rwxr-xr-x 1 root root  312 Dec 10 17:30 sqm
lrwxrwxrwx 1 root root   33 Sep  6  2020 wide-dhcpv6-client -> ../../wide-dhcpv6/dhcp6c-ifupdown