Thank you for using Ubuntu and reporting a bug. Please note that 'sudo ufw disable' will flush the ufw chains and make them all 'pass through' (ie, think of them as NOPs) until reboot. On reboot, ufw won't run and even the pass through chains won't be added.
Furthermore, unless MANAGE_BUILTINS is set to 'yes' in /etc/default/ufw (it defaults to 'no'), ufw only manages its own chains in an effort to play nice with other software that adds rules to the firewall (eg, libvirt). Looking at your bug description, there are no ufw rules on the system, only rules in LIBVIRT_* chains, which ufw did not add when it was enabled before it was disabled. AFAICS, this is not a bug. ufw is behaving as expected and other software on the system is responsible for adding the aforementioned rules. ** Changed in: ufw (Ubuntu) Status: New => Invalid -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to ufw in Ubuntu. https://bugs.launchpad.net/bugs/1858464 Title: iptable rules are still present after disabling ufw Status in ufw package in Ubuntu: Invalid Bug description: If ufw is disabled, the iptable rules still remain active. This is wrong behavior, if an administrator has asked for the firewall to be disabled then no rules of any kind (except for the default policy ACCEPT) should be present in the iptables list. Actual results: root@r820-jq3yx12:~# iptables -L Chain INPUT (policy ACCEPT) target prot opt source destination LIBVIRT_INP all -- anywhere anywhere Chain FORWARD (policy ACCEPT) target prot opt source destination LIBVIRT_FWX all -- anywhere anywhere LIBVIRT_FWI all -- anywhere anywhere LIBVIRT_FWO all -- anywhere anywhere Chain OUTPUT (policy ACCEPT) target prot opt source destination LIBVIRT_OUT all -- anywhere anywhere Chain LIBVIRT_FWI (1 references) target prot opt source destination ACCEPT all -- anywhere 192.168.122.0/24 ctstate RELATED,ESTABLISHED REJECT all -- anywhere anywhere reject-with icmp-port-unreachable Chain LIBVIRT_FWO (1 references) target prot opt source destination ACCEPT all -- 192.168.122.0/24 anywhere REJECT all -- anywhere anywhere reject-with icmp-port-unreachable Chain LIBVIRT_FWX (1 references) target prot opt source destination ACCEPT all -- anywhere anywhere Chain LIBVIRT_INP (1 references) target prot opt source destination ACCEPT udp -- anywhere anywhere udp dpt:domain ACCEPT tcp -- anywhere anywhere tcp dpt:domain ACCEPT udp -- anywhere anywhere udp dpt:bootps ACCEPT tcp -- anywhere anywhere tcp dpt:67 Chain LIBVIRT_OUT (1 references) target prot opt source destination ACCEPT udp -- anywhere anywhere udp dpt:bootpc root@r820-jq3yx12:~# ufw status Status: inactive Expected results: root@r820-jq3yx12:~# iptables -P INPUT ACCEPT root@r820-jq3yx12:~# iptables -P FORWARD ACCEPT root@r820-jq3yx12:~# iptables -P OUTPUT ACCEPT root@r820-jq3yx12:~# iptables -t nat -F root@r820-jq3yx12:~# iptables -t mangle -F root@r820-jq3yx12:~# iptables -F root@r820-jq3yx12:~# iptables -X root@r820-jq3yx12:~# iptables -L Chain INPUT (policy ACCEPT) target prot opt source destination Chain FORWARD (policy ACCEPT) target prot opt source destination Chain OUTPUT (policy ACCEPT) target prot opt source destination ProblemType: Bug DistroRelease: Ubuntu 19.10 Package: ufw 0.36-1ubuntu3 ProcVersionSignature: Ubuntu 5.3.0-24.26-generic 5.3.10 Uname: Linux 5.3.0-24-generic x86_64 NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair ApportVersion: 2.20.11-0ubuntu8.2 Architecture: amd64 Date: Mon Jan 6 11:24:18 2020 InstallationDate: Installed on 2019-12-29 (8 days ago) InstallationMedia: Ubuntu-MATE 19.10 "Eoan Ermine" - Release amd64 (20191017) PackageArchitecture: all ProcEnviron: TERM=xterm-256color PATH=(custom, no user) LANG=en_US.UTF-8 SHELL=/bin/bash SourcePackage: ufw UpgradeStatus: No upgrade log present (probably fresh install) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/ufw/+bug/1858464/+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