winbind name resolution fails when remote host has multiple IPs

[Brian Turek]

Description: Ubuntu 18.04.1 LTS
Release: 18.04

winbind:
  Installed: 2:4.7.6+dfsg~ubuntu-0ubuntu2.2
  Candidate: 2:4.7.6+dfsg~ubuntu-0ubuntu2.2
  Version table:
 *** 2:4.7.6+dfsg~ubuntu-0ubuntu2.2 500
        500 http://gb.archive.ubuntu.com/ubuntu bionic-updates/main amd64 Packages
        500 http://security.ubuntu.com/ubuntu bionic-security/main amd64 Packages
        100 /var/lib/dpkg/status
     2:4.7.6+dfsg~ubuntu-0ubuntu2 500
        500 http://gb.archive.ubuntu.com/ubuntu bionic/main amd64 Packages

This is essentially a confirmation of https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=825380

I had the combination of smb and autofs working in Ubuntu 16.04 and then recently upgraded to 18.04. I hadn't checked my back-up logs that used autofs+smb for a while but today noticed that autofs claimed that it could not resolve my Win10 hostname (the remote backup endpoint). I found the above Debian bug report and can confirm that the issue is present in 18.04.

Steps to reproduce:
# ping abcomputer
ping: abcomputer : System error

# nmblookup abcomputer
192.168.1.8 abcomputer<00>
192.168.5.1 abcomputer<00>

Note the 192.168.5.1 IP is a Virtualbox host-only interface on the Win10 machine. I then remove the host-only interface from the Win10 computer

# nmblookup abcomputer
192.168.1.8 abcomputer<00>

# ping hyperion
PING abcomputer (192.168.1.8) 56(84) bytes of data.
64 bytes from 192.168.1.8 (192.168.1.8): icmp_seq=1 ttl=128 time=0.533 ms

[Christian Ehrhardt  (paelzer)]

The Debian bug is closed by accident, the root cause was not fixed, just an issue that came up while checking.

I'll have to ask andreas to take a look and let you know (he knows samba much better than I do).
Subscribing him

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Robert Kadwell (robertkadw)]

One should disable the "Microsoft Network Client" filter on all unnecessary interfaces in Windows.

[Christian Ehrhardt  (paelzer)]

Has anyone tried the more recent samba versions like 2:4.11.5+dfsg-1ubuntu2 in Focal in regard to this bug?

[Brian Turek (brian-turek)]

I can confirm that this issue still exists in Focal:

# apt info winbind
Package: winbind
Version: 2:4.11.6+dfsg-0ubuntu1.1

$ nmblookup server-without-vbox
192.168.x.y server-without-vbox<00>

$ ping -c 1 server-without-vbox
PING server-without-vbox(192.168.x.y) 56(84) bytes of data.
64 bytes from 192.168.x.y (192.168.x.y): icmp_seq=1 ttl=64 time=0.612 m

$ nmblookup desktop-with-vbox
192.168.x.z desktop-with-vbox<00>
192.168.8.1 desktop-with-vbox<00>

$ ping desktop-with-vbox
ping: desktop-with-vbox: System error

[Christian Ehrhardt  (paelzer)]

Hi,
I come by trying to close or revive bugs that are dormant for too long.

In the meantime this has hit others, but with even less replies/activity :-/
- https://bbs.archlinux.org/viewtopic.php?id=245628

Even a decade ago the workaround was and seems to stay "disable netbios over tcp/ip for
the address you don't want" [1] up to this day.

Summary:
- Debian stated this fixed in 2:4.5.2+dfsg-1 but if you read the case that isn't true.
- And (thanks Brian) it is also still present in Focal

TODO from here:
- Sadly so much time has passed that it makes sense to ask to retry with jammy
- In general a repro on the developer side would make sense

Question: maybe if one has them handy, are there steps to repro this without a windows system. For example two Ubuntu VMs - of which one gets a few extra virtual interfaces and then forcing it somehow to provide more than one of those IPs via wins? From experience in other cases that linux-only repro helps to get traction.

[1]: https://samba.samba.narkive.com/RoKEik9Z/help-mounting-a-windows-computer-with-two-ip-addresses

[R. Diez (rdiezmail-ubuntu)]

I can confirm that this problem still exists in Ubuntu MATE 22.04.1.

I have a Windows PC with 2 IP addresses (because it has 2 network cards), and I get "ping: my-windows-hostname: System error". Other Windows boxes with only 1 IP address work fine.

[Sergio Durigan Junior (sergiodj)]

Thank you for confirming that the bug still exists, R. Diez.

Someone from our team will take a look at this issue soon.