As a workaround, add a flush for the nat chains you want flushed at beginning of the section like this:
*nat :PREROUTING ACCEPT [4:478] :INPUT ACCEPT [4:478] :OUTPUT ACCEPT [0:0] :POSTROUTING ACCEPT [0:0] -F POSTROUTING -A POSTROUTING -o eth0 -j MASQUERADE -A POSTROUTING -o eth0 -j MASQUERADE COMMIT Warrning: This WILL also delete rules which may have been put there by other tools! ONLY do this if ufw is the only tool managing the specific tables/ chains (here: nat POSTROUTING) -- 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/881137 Title: UFW does not clean iptables setting from /etc/ufw/before.rules Status in ufw package in Ubuntu: Won't Fix Bug description: Adding some additional settings to /etc/ufw/before.rules is not deleted when ufw is stopped. I added these lines at top of file /etc/ufw/before.rules *nat :POSTROUTING ACCEPT [0:0] -A POSTROUTING -o eth0 -j MASQUERADE COMMIT Then I reloaded ufw firewall with command: ufw reload. Output from iptables-save $ iptables-save -t nat *nat :PREROUTING ACCEPT [4:478] :INPUT ACCEPT [4:478] :OUTPUT ACCEPT [0:0] :POSTROUTING ACCEPT [0:0] -A POSTROUTING -o eth0 -j MASQUERADE COMMIT Then I reloaded ufw firewall again: $ iptables-save -t nat *nat :PREROUTING ACCEPT [4:478] :INPUT ACCEPT [4:478] :OUTPUT ACCEPT [0:0] :POSTROUTING ACCEPT [0:0] -A POSTROUTING -o eth0 -j MASQUERADE -A POSTROUTING -o eth0 -j MASQUERADE COMMIT And ufw reload again $ iptables-save -t nat *nat :PREROUTING ACCEPT [4:478] :INPUT ACCEPT [4:478] :OUTPUT ACCEPT [0:0] :POSTROUTING ACCEPT [0:0] -A POSTROUTING -o eth0 -j MASQUERADE -A POSTROUTING -o eth0 -j MASQUERADE -A POSTROUTING -o eth0 -j MASQUERADE COMMIT And again and postrouting is never deleted when ufw is stopped and added again when stared. Same happen if I stop ufw firewall with: $ stop ufw. nat lines are not cleaned. UFW should remove all iptables settings specified in config files after ufw is stopped! This can be dangerous if apt-get is updating some ufw files and scripts needs to reload ufw (some lines will be more times). To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/ufw/+bug/881137/+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
