detly's questions

I'm running Ubuntu 18.04 (upgraded from some earlier version) which uses Network Manager and systemd-resolved for name resolution. When I boot, my ethernet connection enp0s31f6 is brought up by Network Manager and given three nameserver addresses via DHCP, 10.1.13.10, 10.1.141.10, 10.1.13.36. Running nmcli shows the three nameservers under "DNS configuration". Running systemd-resolve --status shows them under a "Link 2 (enp0s31f6)" section. I can ping each one. No other connection is active.

testuser ☼ systemd-resolve --status
Global
          DNS Domain: (my org's domain)
          DNSSEC NTA: 10.in-addr.arpa
                      16.172.in-addr.arpa
                      168.192.in-addr.arpa
                      17.172.in-addr.arpa
                      18.172.in-addr.arpa
                      19.172.in-addr.arpa
                      20.172.in-addr.arpa
                      21.172.in-addr.arpa
                      22.172.in-addr.arpa
                      23.172.in-addr.arpa
                      24.172.in-addr.arpa
                      25.172.in-addr.arpa
                      26.172.in-addr.arpa
                      27.172.in-addr.arpa
                      28.172.in-addr.arpa
                      29.172.in-addr.arpa
                      30.172.in-addr.arpa
                      31.172.in-addr.arpa
                      corp
                      d.f.ip6.arpa
                      home
                      internal
                      intranet
                      lan
                      local
                      private
                      test

Link 3 (wlp4s0)
      Current Scopes: none
       LLMNR setting: yes
MulticastDNS setting: no
      DNSSEC setting: no
    DNSSEC supported: no

Link 2 (enp0s31f6)
      Current Scopes: DNS
       LLMNR setting: yes
MulticastDNS setting: no
      DNSSEC setting: no
    DNSSEC supported: no
         DNS Servers: 10.1.13.10
                      10.1.141.10
                      10.1.13.36
          DNS Domain: (my org's domain)

However, when I actually try to resolve a name, even the name of one of the nameservers, dig claims that "connection timed out: no servers could be reached".

testuser ☼ dig dcpdc001.(my org's domain)

; <<>> DiG 9.11.3-1ubuntu1.1-Ubuntu <<>> dcpdc001.(my org's domain)
;; global options: +cmd
;; connection timed out; no servers could be reached

Note that this name should resolve to 10.1.13.10, the first nameserver.

I have configured resolvconf to use dynamic updates. /etc/resolv.conf points to /run/resolvconf/resolv.conf. This file contains only (non-comments):

nameserver 127.0.0.53
search (my orgs local search domain)

If I add nameserver 10.1.13.10 to this file manually, suddenly dig can resolve again, and anything else that needs to see local names can do so. Removing the nameserver breaks that again.

I don't know much about the servers. They're part of a Windows-based network, but I can use them if I edit resolv.conf manually so I don't think that's the issue, and it implies I don't need to be authenticated to the domain to use them. (I can authenticate to the domain via Ubuntu using Realmd/SSSD, but not if I can't resolve the domain controller...)

The journalctl entries for systemd-resolved show only a few messages about "Using degraded feature set ... for DNS server" but they only refer to the third nameserver, not the others. Nothing for the primary nameserver.

How can I get name resolution working without having to manually edit resolv.conf every time I boot?

I assume the contents of my resolv.conf mean that Network Manager or Systemd has some sort of local caching resolver running? If so, would bypassing it fix things?

I increased the logging level of systemd-resolved and journalctl -f -u systemd-resolved shows:

Jul 20 10:33:23 heerij-ubuntu systemd-resolved[2352]: Got DNS stub UDP query packet for id 19836
Jul 20 10:33:23 heerij-ubuntu systemd-resolved[2352]: Looking up RR for dcpdc001.(org domain) IN A.
Jul 20 10:33:23 heerij-ubuntu systemd-resolved[2352]: Switching to DNS server 10.1.13.10 for interface enp0s31f6.
Jul 20 10:33:23 heerij-ubuntu systemd-resolved[2352]: Cache miss for dcpdc001.(org domain) IN A
Jul 20 10:33:23 heerij-ubuntu systemd-resolved[2352]: Transaction 12728 for <dcpdc001.(org domain) IN A> scope dns on enp0s31f6/*.
Jul 20 10:33:23 heerij-ubuntu systemd-resolved[2352]: Using feature level UDP+EDNS0+DO+LARGE for transaction 12728.
Jul 20 10:33:23 heerij-ubuntu systemd-resolved[2352]: Using DNS server 10.1.13.10 for transaction 12728.
Jul 20 10:33:23 heerij-ubuntu systemd-resolved[2352]: Sending query packet with id 12728.
Jul 20 10:33:23 heerij-ubuntu systemd-resolved[2352]: Processing query...
Jul 20 10:33:23 heerij-ubuntu systemd-resolved[2352]: Timeout reached on transaction 12728.

I have a machine running Ubuntu Server 18.04. The network is configured using Netplan, so I have this config in /etc/netplan/01-netcfg.yaml:

network:
  version: 2
  renderer: networkd
  ethernets:
    enp1s0f0:
      optional: false
      addresses:
        - 10.0.0.1/24    
  wifis:
    wlp2s0:
      optional: true
      dhcp4: yes
      access-points:
        [...]

enp1s0f0 is connected to a device that may or may not be on (at boot or any other time). I want to run a DHCP server on this interface.

The trouble is, when I boot there's a delay of a few minutes and I see this message:

A start job is running for Wait for Network to be Configured

Eventually it times out, the boot continues, but enp1s0f0 is never configured or brought up. ip link show enp1s0f0 gives:

2: enp1s0f0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc mq state DOWN mode DEFAULT group default qlen 1000
    link/ether 10:dd:b1:ef:65:21 brd ff:ff:ff:ff:ff:ff

I have no idea what the significance of NO-CARRIER is, but in case it's relevant, here's the output of sudo lspci -v:

01:00.0 Ethernet controller: Broadcom Limited NetXtreme BCM57766 Gigabit Ethernet PCIe (rev 01)
    Subsystem: Broadcom Limited NetXtreme BCM57766 Gigabit Ethernet PCIe
    Flags: bus master, fast devsel, latency 0, IRQ 16
    Memory at a0400000 (64-bit, prefetchable) [size=64K]
    Memory at a0410000 (64-bit, prefetchable) [size=64K]
    Capabilities: [48] Power Management version 3
    Capabilities: [50] Vital Product Data
    Capabilities: [58] MSI: Enable- Count=1/8 Maskable- 64bit+
    Capabilities: [a0] MSI-X: Enable+ Count=6 Masked-
    Capabilities: [ac] Express Endpoint, MSI 00
    Capabilities: [100] Advanced Error Reporting
    Capabilities: [13c] Device Serial Number 00-00-10-dd-b1-ef-65-21
    Capabilities: [150] Power Budgeting <?>
    Capabilities: [160] Virtual Channel
    Capabilities: [1b0] Latency Tolerance Reporting
    Kernel driver in use: tg3
    Kernel modules: tg3

Now if I turn the attached device on, sure enough enp1s0f0 comes up:

2: enp1s0f0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP mode DEFAULT group default qlen 1000
    link/ether 10:dd:b1:ef:65:21 brd ff:ff:ff:ff:ff:ff

But it's of no use at this point — the DHCP server won't work, because it couldn't start with enp1s0f0 no up at boot time. I need enp1s0f0 up and configured during boot, which I thought was the whole point of a static IP configuration. Even stranger is that it always has an IPv6 address, even when it's down:

2: enp1s0f0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc mq state DOWN group default qlen 1000
    link/ether 10:dd:b1:ef:65:21 brd ff:ff:ff:ff:ff:ff
    inet6 fe80::12dd:b1ff:feef:6521/64 scope link 
       valid_lft forever preferred_lft forever

If I check Netplan's debug output, I see:

$ sudo netplan --debug apply
** (generate:1555): DEBUG: 20:39:27.253: Processing input file //etc/netplan/01-netcfg.yaml..
** (generate:1555): DEBUG: 20:39:27.254: starting new processing pass
** (generate:1555): DEBUG: 20:39:27.254: wlp2s0: adding wifi AP 'Jeff Winger's Wireless Hairbrush'
** (generate:1555): DEBUG: 20:39:27.254: wlp2s0: setting default backend to 1
** (generate:1555): DEBUG: 20:39:27.254: enp1s0f0: setting default backend to 1
** (generate:1555): DEBUG: 20:39:27.254: Generating output files..
** (generate:1555): DEBUG: 20:39:27.254: wlp2s0: Creating wpa_supplicant configuration file run/netplan/wpa-wlp2s0.conf
** (generate:1555): DEBUG: 20:39:27.254: Creating wpa_supplicant service enablement link /run/systemd/system/multi-user.target.wants/[email protected]
** (generate:1555): DEBUG: 20:39:27.254: NetworkManager: definition wlp2s0 is not for us (backend 1)
** (generate:1555): DEBUG: 20:39:27.254: NetworkManager: definition enp1s0f0 is not for us (backend 1)
DEBUG:netplan generated networkd configuration exists, restarting networkd
DEBUG:no netplan generated NM configuration exists
DEBUG:replug enp1s0f0: unbinding 0000:01:00.0 from /sys/bus/pci/drivers/tg3
DEBUG:replug enp1s0f0: rebinding 0000:01:00.0 to /sys/bus/pci/drivers/tg3
DEBUG:device wlp2s0 operstate is up, not replugging
DEBUG:netplan triggering .link rules for wlp2s0
DEBUG:device lo operstate is unknown, not replugging
DEBUG:netplan triggering .link rules for lo

My configuration for isc-dhcp-server is to have /etc/default/isc-dhcp-server contain:

INTERFACESv4="enp1s0f0"

...and /etc/dhcp/dhcpd.conf contain (amongst other things):

subnet 10.0.0.0 netmask 255.255.255.0 {
...
}

In theory, this should serve DHCP over enp1s0f0. However, since enp1s0f0 is never brought up, the DHCP server fails to start:

No subnet declaration for enp1s0f0 (no IPv4 addresses).
** Ignoring requests on enp1s0f0.  If this is not what
   you want, please write a subnet declaration
   in your dhcpd.conf file for the network segment
   to which interface enp1s0f0 is attached. **


Not configured to listen on any interfaces!

This wasn't an issue under ifupdown (I have no idea why enp1s0f0 doesn't just come up during boot, whether or not anything is at the other end of the cable; I thought that was the whole point of having a static IP). Is it possible to get it working in Netplan? Or is it possible to have the DHCP server start when enp1s0f0 is up?

As per this answer to the question "Can I continue working when backup is in progress?," the default backup software in Ubuntu, Deja Dup, is prone to consistency issues when backing up. That is, if the user changes files on a writeable filesystem while the backup is being done, the backup might not be in a sensible state, and restoring it in full will restore a broken system. Even restoring individual files might restore broken files.

The advice to not do any work while the backup is going is a workaround, but not really practical. A user "not working" doesn't mean files aren't being modified behind the scenes.

The answer I linked to says this about snapshots:

This can be achieved using LVM or a newer generation filesystem such as BtrFS. This will snapshot the whole volume as if you were taking a picture of it. Changes/writes are still possible, but the backup process is being run from the read-only snapshot taken earlier.

For example, on Windows systems most backup software runs on a "shadow copy," a semantically consistent snapshot of the filesystem maintained by the OS. The user can continue working, and further modifications will not be part of the currently running backup.

However, I don't know that Deja Dup on Ubuntu uses any kind of snapshotting if it's available.

My question is: is there any automated backup software for Ubuntu that:

• is easy to use, via a GUI, suitable for users unwilling to use the command line or write their own scripts
• ensures consistency of backups using snapshots, or enforcing read-only on the source of the backup (heavy-handed but perfectly valid), or any other approach to avoid inconsistency?

One of my attempts to work around this problem with VPN DNS in 17.04 was to duplicate my existing wifi connection but with different DNS entries.

But Gnome's Network Settings UI appears to have no way to add a connection to a wifi access point if the SSID is already known to another connection profile. If I try to add it as a hidden network (where I can manually enter the SSID), it simply detects that I already have a system wide profile for it and prompts me to authenticate to change it, preventing me from adding a second one.

Is it possible to have two different sets of connection settings to the one wifi access point?

I have a variety of OpenVPN VPN servers I connect to from my Ubuntu 17.04 machine, all of which push DNS servers using the dhcp-option DNS A.B.C.D (which I know is a Windows extension, but that's how they're pushed). The DNS servers (for each provider) change rarely, so I can also enter them manually if need be.

I add a VPN using its .ovpn config file via Gnome's Network Settings ("+" > "Import from file..."), making it available only to the current user. By contrast, the physical connection is a wifi connection available to all users.

The VPN's DNS servers are simply not used by the system. If I just accept the config as given in the file, the VPN connects but the DNS servers don't even appear in the output of systemd-resolve --status. If I add them to the IPv4 settings manually, they do but are not used.

For example, before connecting, the output of systemd-resolve --status shows this at the end:

Link 3 (wlp3s0)
      Current Scopes: DNS LLMNR/IPv4 LLMNR/IPv6
       LLMNR setting: yes
MulticastDNS setting: no
      DNSSEC setting: no
    DNSSEC supported: no
         DNS Servers: 192.168.1.1

Link 2 (enp0s31f6)
      Current Scopes: none
       LLMNR setting: yes
MulticastDNS setting: no
      DNSSEC setting: no
    DNSSEC supported: no

192.168.1.1 is my router. After connecting to the VPN I see this extra entry above the others:

Link 9 (tun0)
      Current Scopes: DNS
       LLMNR setting: yes
MulticastDNS setting: no
      DNSSEC setting: no
    DNSSEC supported: no
         DNS Servers: A.B.C.D
                      E.F.G.G

A.B.C.D etc. stand for the DNS of the VPN provider. However, I've confirmed via packet inspection that even with these new entries, DNS lookups are done via 192.168.1.1 which just uses my ISP's servers.

For completeness, ip route show gives:

$ ip route show
default via 10.7.7.1 dev tun0 proto static metric 50 
default via 192.168.1.1 dev wlp3s0 proto static metric 600 
10.7.7.0/24 dev tun0 proto kernel scope link src 10.7.7.182 metric 50 
I.J.K.L via 192.168.1.1 dev wlp3s0 proto static metric 600 
169.254.0.0/16 dev wlp3s0 scope link metric 1000 
192.168.1.0/24 dev wlp3s0 proto kernel scope link src 192.168.1.193 metric 600 
192.168.1.1 dev wlp3s0 proto static scope link metric 600 

(I.J.K.L is the VPN address.) It seems weird that there are too different default routes, but I guess the metric is meant to take care of that?

Whatever the cause, I want to be using the VPN provider's DNS when I'm connected to the VPN, and not use them when I'm not. I considered trying to create a second Network Manager profile for my wifi access point with the provider's DNS entries, but it turns out you can't create a second (or user specific) profile for an access point that Network Manager already knows about.

Things I'd prefer to avoid:

• Modify the .ovpn config files. I have about a hundred of these, and they're updated regularly by the VPN providers.
• Permanently change DNS servers for the system-wide connection used for wifi, or for the router itself. I only want to use the VPN's DNS servers when I'm connected to a VPN.
• Run a command manually every time I connect to a VPN. I or another user could easily forget to do this.

For the sake of experimentation, I am trying to document a minimal procedure for a pure EFI boot of 14.04 on a Mac Mini.

This involves installing a base system (using the Mac-flavoured server install ISO) to the hard drive, but NOT installing GRUB to the MBR. GRUB is installed to the first partition of the hard drive, but until I manually set up the EFI boot partition, the system will be unbootable.

Is there a way to use the bootloader on the USB installer to boot into the installed system manually? I have access to "advanced options" (ie. the bootloader command line) on the installer, but I don't know what bootloader it is, and so I can't find full documentation for it.

I use a few programs that do spellchecking via hunspell, but they seem to check against US English. It'd be beaut if they'd use Australian English (maaaaybe UK English if there's Buckley's of Strine).

My language-related environment variables look right:

LANG=en_AU.UTF-8
LANGUAGE=en_AU:en

I've fossicked about for any hunspell-en-au|gb|etc packages, but they seem to have gone bush in 14.04. What's the fix?

I have tweaked my mouse sensitivity to be just right, and swapped the mouse buttons since I use it left-handed. This was done using the user "Mouse & Touchpad" settings in Gnome.

I'd like this to apply to the login screen and all other user sessions (since they're all mine as well anyway). I'm using Gnome 3.8 under 13.10, but other sessions might use Unity or XFCE.

How do I apply my session mouse settings globally?

Under Ubuntu 12.10, whenever I visit a new domain in Chromium, a bar appears at the top of the window saying Unity WebApps needs your permission to run. [Always run on this site] [Run this time].

I want Unity WebApps to work, but I don't want to be asked this for every single site I visit. How can I stop this notification appearing?

I have a Microsoft Sculpt Touch bluetooth mouse, and a bluetooth/USB dongle.

I have tried to pair with the mouse by going to System Settings > Bluetooth and clicking on the "+" button to add a device. This launches the Bluetooth New Device Setup wizard, which lists the mouse at the Device Search stage.

I can only click "Continue" on the wizard if I select a PIN option (or tell it not to use one). But I always just see:

Connecting to '(null)'...

...followed by:

Setting up '(null)' failed.

How do I connect to and use the mouse?

The dongle is listed by lsusb as:

Bus 005 Device 002: ID 0a12:0001 Cambridge Silicon Radio, Ltd Bluetooth Dongle (HCI mode)

After plugging it in, dmesg shows:

[  256.876091] usb 5-1: new full-speed USB device number 2 using uhci_hcd
[  257.132851] Bluetooth: Generic Bluetooth USB driver ver 0.6
[  257.135389] usbcore: registered new interface driver btusb

I'm using 12.04 with kernel 3.2.0-35-generic.

I am trying to convert video to the formats commonly used for HTML5 embedding — that is, MP4 (H264 + AAC), OGV (Theora + Vorbis) and WebM (VP8 + Vorbis). I would like to use a GUI application to do this as simply as possible.

I have the Medibuntu repository installed, but it doesn't seem to help. Avidemux is missing the H264 video encoder, and Handbrake only does MP4 (not the other two). How can I configure these apps under 11.10 for my purposes, or alternatively, what else is there?

When I run qemu -cpu kvm64 -snapshot -hda binary.img at a local console, the image boots and runs as I expect. However, when I log in via ssh -C -X, I see:

$ qemu -cpu kvm64 -snapshot -hda binary.img 
open /dev/kvm: Permission denied
Could not initialize KVM, will disable KVM support
qemu: pci_add_option_rom: failed to find romfile "pxe-rtl8139.bin"

(The pxe-rtl8139 message is there when run locally as well, it doesn't seem to matter.)

Why does using SSH make a difference? How can I run qemu over SSH without needing root permissions?

Both machines are Ubuntu 11.10, qemu and qemu-kvm are 0.14.1+noroms-0ubuntu6.2

Where (under my home directory) do I put Python extensions for Nautilus 3?

I opened the introduction in LyX and used Ctrl+R to view it in evince. The fonts appear nice and smooth. If I copy and paste the first couple of paragraphs into a new document and render that, the fonts have jagged, pixellated edges (especially visible upon zooming).

This is with no customisation to LyX at all — a fresh installation via Synaptic. I can't see any differences between the document settings for the new documents (although there are probably some differences due to autodetection).

How can I make the fonts look smooth in my own documents? Particularly of the article class and beamer presentations?

How can I remove the entire messaging menu for one particular user (and not all other users) under Unity or Unity-2D in Ubuntu 11.10?

I would like to be able to graphically log in to another Ubuntu machine (the server) from my Ubuntu desktop machine (the client), much like with Windows' Remote Desktop.

The "Desktop Sharing" settings that come installed by default seem to use VNC. VNC is a bit of a bandwidth hog, can only work at the resolution of whatever screen is attached to the host, requires you to log in at the machine itself, and mirrors every action on the host.

I know about X tunnelling, but that's annoying to use and doesn't always work properly (or, more accurately, some apps don't work properly).

Is there any kind of tool in between the two, similar to Remote Desktop used for Windows? Specifically, something with the following features:

• can run at a different resolution to the host screen (if there is one)
• can run at full screen
• has adjustable quality settings for different bandwidths
• doesn't require a user to be logged in locally
• saves credentials or uses SSH keys
• starts automatically on the server
• client works under Gnome 3 and Unity
• can be restricted to work with non-compositing DEs on the server (eg. XFCE)

I've been using X2go for a while, but unfortunately it no longer works fullscreen on Gnome 3 due to a couple of bugs (#1072 and #982), so if there's a better solution out there I'd like to try it.

After setting up my accounts with Gwibber, there is only one column showing all messages from each account. There are no controls or options to add columns, or to change what is seen in the single visible column (except to switch to replies or private messages). It is also impossible to change themes — the "Preferences" dialog has only "Options" and "Messages". This was all configurable in previous versions, so how do I configure Gwibber now?

This is on Ubuntu 11.10 with:

• unity 4.24.0-0ubuntu2.1
• libgtk-3-0 3.2.0-0ubuntu3
• gwibber 3.2.1-0ubuntu1.3

I am also using the Zukitwo Hybrid (blue) theme, installed manually and activated via the gnome-tweak-tool.

How do I disable the tracking and display of recently opened files (and whatever else is remembered) in a default installation of Ubuntu? (This question originally concerned 11.10, but now that I'm on 12.04, that's the answer I've selected.)

(Note that this is not a duplicate of How can I keep recent files from appearing in Unity?, since that question and its answers are concerned with temporary and specific filtering. I want to disable it completely for a single user account.)

Okay, to deflect the inevitable and expand on my motivation...

While trawling the usual forums and Google results for a solution, it (unsurprisingly) seems that the near-universal use cases for this request are either browsing porn or Warhammer research. And the obvious solution to this is to create another user account to contain all evidence.

However, this is not why I'm asking, and I don't say that to get all high and mighty about it, it's because this answer won't help. (Even though I really don't have any interest in Warhammer, and I have no idea how that paint pot and brush ended up in my drawer, no that's not glue on my thumb, etc.)

My actual use case is that I use my personal laptop for presentations in different circles of my life. I have a user account set up with all the settings I like for presentations (shortcuts, small launcher, default associations, etc). But I don't want an accidental keystroke (or the find dialog) to display other recent presentations I've given, or the files I used in composing the presentation, or whatever. I also don't want to have to recreate this profile for every single presentation I might give. I just want a nice little isolated, memoryless, clean corner of my notebook for public display.

How do I hide a particular user from the login screen on a default install of 11.10 and higher? (ie. using Unity Greeter)?

The last time I installed Truecrypt (on Debian) I built the package myself. I'm now on Ubuntu 11.04 and I'd rather not do that again. The only download they have on their site is a tarball, but I prefer to install from a package than manually where possible.

Is there an actively maintained PPA or repository somewhere with Truecrypt for Ubuntu 11.04, or even just built packages available to download?

(I realise it's kept out of Ubuntu and Launchpad because of licensing issues, but that doesn't mean there isn't another repo elsewhere...)