I'm so sorry this is so complex, but I couldn't figure out any simpler way to reproduce as they components involved do network configuration.
Anyway, please find attached a docker compose file and related dnsmasq configurations (mapped automatically in that compose file) that helps in the reproduction by setting up two different dhcp servers based on dnsmasq (focal and jammy) and a machine that can be used to request a dhcp address. To reproduce the bug: 1) first install everything needed by running docker-compose up -d 2) wait until everything has been installed, check for example that the output of has something from all 3 containers and is not getting any more lines docker-compose logs --follow 3) stop jammy version of the server with docker-compose stop jammy-server 4) get inside client machine to run dhclient. Run it first without fake relay address, then with one (to trigger the DHCP relay behaviour in dnsmasq) docker-compose exec client bash dhclient -d -v (ctrl-c after a while) dhclient -d -v -g 192.168.0.10 (ctrl-c after a while) 5) observe server's log dnsmasq-script-sample-focal-server-1 | dnsmasq-dhcp: DHCPREQUEST(eth0) 192.168.0.3 02:42:c0:a8:00:04 dnsmasq-script-sample-focal-server-1 | dnsmasq-dhcp: DHCPACK(eth0) 192.168.0.3 02:42:c0:a8:00:04 5a49beb3cd53 dnsmasq-script-sample-focal-server-1 | hello from dhcp hook script, IP argument is 192.168.0.3 dnsmasq-script-sample-focal-server-1 | dnsmasq-dhcp: DHCPREQUEST(eth0) 192.168.0.3 02:42:c0:a8:00:04 dnsmasq-script-sample-focal-server-1 | dnsmasq-dhcp: DHCPACK(eth0) 192.168.0.3 02:42:c0:a8:00:04 5a49beb3cd53 dnsmasq-script-sample-focal-server-1 | hello from dhcp hook script, IP argument is 192.168.0.3 6) now stop focal version of server and start jammy: docker-compose stop focal-server docker-compose start jammy-server 7) repeat steps 5 and 6, this time the output has the wroing ip in the 2nd hook script invocation dnsmasq-script-sample-jammy-server-1 | dnsmasq-dhcp: DHCPREQUEST(eth0) 192.168.0.1 02:42:c0:a8:00:04 dnsmasq-script-sample-jammy-server-1 | dnsmasq-dhcp: DHCPACK(eth0) 192.168.0.1 02:42:c0:a8:00:04 5a49beb3cd53 dnsmasq-script-sample-jammy-server-1 | hello from dhcp hook script, IP argument is 192.168.0.1 dnsmasq-script-sample-jammy-server-1 | dnsmasq-dhcp: DHCPREQUEST(eth0) 192.168.0.1 02:42:c0:a8:00:04 dnsmasq-script-sample-jammy-server-1 | dnsmasq-dhcp: DHCPACK(eth0) 192.168.0.1 02:42:c0:a8:00:04 5a49beb3cd53 dnsmasq-script-sample-jammy-server-1 | hello from dhcp hook script, IP argument is 192.168.0.10 ** Attachment added: "archive containing docker-compose.yml and needed configuration files" https://bugs.launchpad.net/ubuntu/+source/dnsmasq/+bug/2042587/+attachment/5716459/+files/sample.tar.gz -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to dnsmasq in Ubuntu. https://bugs.launchpad.net/bugs/2042587 Title: jammy's version breaks existing dhcp scripts with relay Status in dnsmasq package in Ubuntu: Incomplete Bug description: When upgrading from focal to jammy, existing dnsmasq dhcp-scripts stopped working in an environment where a DHCP relay is in use. Instead of the expected client IP address, the script gets the _relay_ IP address as an argument. From dnsmasq documentation for --dhcp- script: > The arguments to the process are "add", "old" or "del", the MAC address of the host (or DUID for IPv6) , the IP address, and the hostname, if known. I believe the change has been inadverently made in upstream commit 527c3c7d0d3bb4bf5fad699f10cf0d1a45a54692 (https://thekelleys.org.uk/gitweb/?p=dnsmasq.git;a=blobdiff;f=src/helper.c;h=02340a01c00031db0cc682c8a4a279cfc1db574e;hp=d81de9622e6d484a264496b2cd3638b4e15e9677;hb=527c3c7d0d3bb4bf5fad699f10cf0d1a45a54692;hpb=fcb4dcaf7cc8a86ac2533b933161b6455f75bf8f) as the commit message only speaks about inet_ntoa replacement and not the behavioral change it also introduces (previously the relay address was only set to the environment variable, now it effectively overrides the prevoiusly set client's IP address). dnsmasq 2.86-1.1ubuntu0.3 / Ubuntu 22.04 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/dnsmasq/+bug/2042587/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp
