I've tested the package from -proposed and I can confirm it fixes the problem:
Installed from -proposed: root@ubuntu:~# apt-cache policy klibc-utils klibc-utils: Installed: 2.0.4-9ubuntu2.2 Candidate: 2.0.4-9ubuntu2.18.04.1 Version table: 2.0.4-9ubuntu2.18.04.1 500 500 http://ppa.launchpad.net/mfo/lp1947099/ubuntu bionic/main amd64 Packages *** 2.0.4-9ubuntu2.2 500 500 http://archive.ubuntu.com/ubuntu bionic-proposed/main amd64 Packages 100 /var/lib/dpkg/status 2.0.4-9ubuntu2.1 500 500 http://archive.ubuntu.com/ubuntu bionic-updates/main amd64 Packages 500 http://security.ubuntu.com/ubuntu bionic-security/main amd64 Packages 2.0.4-9ubuntu2 500 500 http://archive.ubuntu.com/ubuntu bionic/main amd64 Packages Working well without timeout: root@ubuntu:~# ip l set dev ens9 down root@ubuntu:~# date; /usr/lib/klibc/bin/ipconfig ens9; date Thu May 12 12:54:48 UTC 2022 IP-Config: ens9 hardware address 52:54:00:f3:4e:0e mtu 1500 DHCP RARP IP-Config: ens9 complete (dhcp from 192.168.150.2): address: 192.168.150.105 broadcast: 192.168.150.255 netmask: 255.255.255.0 gateway: 192.168.150.1 dns0 : 192.168.150.2 dns1 : 0.0.0.0 domain : sts.lab rootserver: 192.168.150.2 rootpath: filename : Thu May 12 12:55:01 UTC 2022 Timeout being honored: root@ubuntu:~# ip l set dev ens9 down root@ubuntu:~# date; /usr/lib/klibc/bin/ipconfig -t 2 ens9; date Thu May 12 12:55:44 UTC 2022 IP-Config: ens9 hardware address 52:54:00:f3:4e:0e mtu 1500 DHCP RARP Lowered timeout to match user request = (2 s) IP-Config: no response after 2 secs - giving up Thu May 12 12:55:46 UTC 2022 Testing the original issue (timeout being ignored when not receiving any reply from a DHCP Server), which is now also getting honored: root@ubuntu:~# ip l set dev ens9 down root@ubuntu:~# date; /usr/lib/klibc/bin/ipconfig -t 2 ens9; date Thu May 12 12:56:32 UTC 2022 IP-Config: ens9 hardware address 52:54:00:f3:4e:0e mtu 1500 DHCP RARP Lowered timeout to match user request = (2 s) IP-Config: no response after 2 secs - giving up Thu May 12 12:56:34 UTC 2022 root@ubuntu:~# ip l set dev ens9 down root@ubuntu:~# date; /usr/lib/klibc/bin/ipconfig -t 5 ens9; date Thu May 12 12:56:43 UTC 2022 IP-Config: ens9 hardware address 52:54:00:f3:4e:0e mtu 1500 DHCP RARP Lowered timeout to match user request = (5 s) IP-Config: no response after 5 secs - giving up Thu May 12 12:56:48 UTC 2022 -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1947099 Title: ipconfig does not honour user-requested timeouts in some cases To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/klibc/+bug/1947099/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs