Um... I observed that it happens because my wireless interface is down when knockd is about to start. It usually happens during boot and after the machine resumed from suspend.
I thought I'll give a try to "After=network-online.target" option for the systemd config of knockd but I didn't find any configuration. It looks like there's an old-style init script under the hood. Finally I wrote a bash script that starts or stops knockd when the interface is up/down, made it executable and placed to /etc/NetworkManager/dispatcher.d/ - it's working now. ** Attachment added: "Workaround" https://bugs.launchpad.net/ubuntu/+source/knockd/+bug/837954/+attachment/4505920/+files/90nmknockd -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/837954 Title: knockd service fails to start when connecting with NetworkManager To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/knockd/+bug/837954/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
