Message 2 of 2: This is easy to use and/or test ifup dummy0 and ifdown dummy0
You don't need to know the complexities of the motivation for why this is important; the test case is very simple. In the context of the ifupdown package, this requires putting a stanza like this in /etc/network/interfaces or /etc/network/interfaces.d/dummy: auto dummy0 iface dummy0 inet static netmask 255.255.255.255 address 10.10.2.105 Then the static dummy interface (a) should come up automagically at boot time, and can be further controlled by :; ifup dummy0 :; ifdown dummy0 Desired behavior: It should just work. Observed behavior: :; ifup dummy0 Cannot find device "dummy0" Failed to bring up dummy0. Highly informative workaround: :; ip link add dummy0 type dummy That command works, and makes the problem go away permanently. The ifup and ifdown commands work fine after that. For convenient debugging, you can use the command: :; ip link del dummy0 type dummy which makes the problem come back. You can also experiment with dummy1 et cetera. See the detailed workaround script attached previously. FWIW the ifconfig command exhibits all the same misbehavior; net-tools and ifupdown are affected in the same way, but remarkably enough the ip command (from the iproute2 package) is apparently not affected by this bug. -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to ifupdown in Ubuntu. https://bugs.launchpad.net/bugs/1828749 Title: ifconfig dummy0 : Device not found Status in ifupdown package in Ubuntu: Incomplete Status in net-tools package in Ubuntu: New Bug description: Desired behavior: The ifconfig command should be able to deal with the dummy device. This worked fine until recently. Observed behavior: :; ifconfig dummy0 dummy0: error fetching interface information: Device not found This problem appeared when I upgraded to bionic. Highly informative workaround: :; ip link add dummy0 type dummy That command works, and makes the problem go away permanently. The ifconfig command works fine after that. The ifup and ifdown commands also work fine after that. For convenient debugging, you can use the command: :; ip link del dummy0 type dummy which makes the problem come back. You can also experiment with dummy1 et cetera. Package ownership issues: Compare: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=909204 That report was filed against ippusbxd, which is almost certainly not the relevant package. For that matter, I have no idea whether the root cause is in the net-tools package or the kernel networking stack. All I know is the ip command plays nicely with the kernel while the ifconfig command does not. Notes: The kernel module for the dummy interface is preloaded in all situations described here. That's not the issue. An apport file is attached, to describe the environment. Also, since you asked: :; apt-cache policy net-tools net-tools: Installed: 1.60-26ubuntu1 Candidate: 1.60-26ubuntu1 Version table: *** 1.60-26ubuntu1 500 500 http://ubuntu.cs.utah.edu/ubuntu xenial/main amd64 Packages 100 /var/lib/dpkg/status :; lsb_release -rd Description: Ubuntu 16.04.6 LTS Release: 16.04 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/ifupdown/+bug/1828749/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : [email protected] Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp
