Package: ifupdown Version: 0.8.35 Severity: important I've now run into this problem on several systems running buster. Whenever a script in /etc/network/if-up.d/ fails (see, e.g., #959864) the dhclient instance dies. This behaviour may actually predate buster, but is much more noticeable now that dhclient-script sets the interface's valid_lft to the actual, finite lifetime of the lease (cf. #834532). The result is that the system drops off the network when the initial DHCP lease expires.
I'm not sure how well specified the behaviour of ifup is on script failure; I couldn't find it documented. Maybe this needs to be clarified? That's also why I've filed a bug against postfix, whose if-up.d script really shouldn't be failing so casually. Still, doing things halfway (killing dhclient but leaving the interface up) doesn't feel right. I'd rather deal with an immediate failure than with a delayed one. Here is information about the same incident as in #959864, but with a focus on ifup rather than postfix. From systemctl status: ● [email protected] - ifup for eno1 Loaded: loaded (/lib/systemd/system/[email protected]; static; vendor preset: enabled) Active: failed (Result: exit-code) since xxxxxxxxxxxxxx 11:56:04 UTC; x days ago Process: 713 ExecStart=/bin/sh -ec ifup --allow=hotplug eno1; ifquery --state eno1 (code=exited, status=1/FAILURE) Main PID: 713 (code=exited, status=1/FAILURE) 11:56:04 HOST dhclient[729]: DHCPACK of 192.168.1.68 from 192.168.1.67 11:56:04 HOST dhclient[729]: bound to 192.168.1.68 -- renewal in 11512 seconds. 11:56:04 HOST sh[713]: bound to 192.168.1.68 -- renewal in 11512 seconds. 11:56:04 HOST sh[713]: Sending network state change signal to nslcd...done. 11:56:04 HOST sh[713]: run-parts: /etc/network/if-up.d/postfix exited with return code 69 11:56:04 HOST sh[713]: ifup: failed to bring up eno1 11:56:04 HOST systemd[1]: [email protected]: Main process exited, code=exited, status=1/FAILURE 11:56:04 HOST systemd[1]: [email protected]: Failed with result 'exit-code'. From process accounting: dhclient-script |v3| 0.00| 0.00| 0.00| 0| 0| 2388.00| 0.00| 1138| 1131| F | 0|__ |xxxxxxxxxx 11:56:04 2020 dhclient-script |v3| 0.00| 0.00| 23.00| 0| 0| 2388.00| 0.00| 1131| 729| | 0|__ |xxxxxxxxxx 11:56:04 2020 dhclient |v3| 0.00| 0.00| 519.00| 0| 0| 8456.00| 0.00| 725| 723| | 0|__ |xxxxxxxxxx 11:55:59 2020 sh |v3| 0.00| 0.00| 519.00| 0| 0| 2388.00| 0.00| 723| 716| | 0|__ |xxxxxxxxxx 11:55:59 2020 postfix |v3| 0.00| 0.00| 0.00| 0| 0| 2388.00| 0.00| 1219| 1217| F | 0|__ |xxxxxxxxxx 11:56:04 2020 postqueue |v3| 1.00| 0.00| 3.00| 0| 0| 45576.00| 0.00| 1222| 1217| | 69|__ |xxxxxxxxxx 11:56:04 2020 postfix |v3| 0.00| 0.00| 4.00| 0| 0| 2388.00| 0.00| 1217| 1194| | 69|__ |xxxxxxxxxx 11:56:04 2020 run-parts |v3| 0.00| 0.00| 13.00| 0| 0| 2284.00| 0.00| 1194| 1193| | 1|__ |xxxxxxxxxx 11:56:04 2020 sh |v3| 0.00| 0.00| 13.00| 0| 0| 2388.00| 0.00| 1193| 716| | 1|__ |xxxxxxxxxx 11:56:04 2020 ifup |v3| 0.00| 0.00| 533.00| 0| 0| 2344.00| 0.00| 716| 713| | 1|__ |xxxxxxxxxx 11:55:59 2020 sh |v3| 0.00| 0.00| 534.00| 0| 0| 2388.00| 0.00| 713| 1|S | 1|__ |xxxxxxxxxx 11:55:59 2020 dhclient |v3| 0.00| 0.00| 520.00| 0| 0| 11416.00| 0.00| 729| 1|SF X| 0|__ |xxxxxxxxxx 11:55:59 2020 Examination of the raw process accounting data (dump-acct doesn't print out this information) reveals that process 729 was killed by signal 15 (SIGTERM).
