[Bug 13470] DFS mounted shares do not allow to go subdirectories

[Bug 13470] DFS mounted shares do not allow to go subdirectories

[samba-bugs]

https://bugzilla.samba.org/show_bug.cgi?id=13470

Aurélien Aptel <aaptel@samba.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |aaptel@samba.org
             Status|NEW                         |NEEDINFO

--- Comment #1 from Aurélien Aptel <aaptel@samba.org> ---
Have you tried a recent kernel? Lot of DFS changes went in the last few years.

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[Bug 13470] DFS mounted shares do not allow to go subdirectories

[samba-bugs]

https://bugzilla.samba.org/show_bug.cgi?id=13470

--- Comment #2 from Sergey <sergey_ilinykh@epam.com> ---
Hi Aurélien Aptel,

Following my scenario above I couldn't reproduce it anymore. Seems to work.

btw I have a couple of questions unrelated to this issue:
1. Is it possible to force smbclient/cifs mount to try all nameservers from
/etc/resolv.conf? 
2. Is it possible to mount dfs root? In my case it's //epam.com

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[Bug 13470] DFS mounted shares do not allow to go subdirectories

[samba-bugs]

https://bugzilla.samba.org/show_bug.cgi?id=13470

--- Comment #3 from Aurélien Aptel <aaptel@samba.org> ---
Regarding 1)

You can put multiple nameservers in /etc/resolv.conf but that might not have
the effect you want.

If you have 2 nameserver A and B, it will try to resolve by contacting A first.
But if A is *up* and replies that the the domain cannot be found it will stop
there.
The nameserver B will only be tried if A is down, not if A replies "doesn't
exist".

What I would suggest you do is setup dnsmasq. It's a tiny dns server proxy
daemon.

You can tell it to forward all domain request for epam.com and any subdomain
(e.g. a.epam.com, a.b.c.epam.com etc) to nameserver A, and forward all the
other request to nameserver B.

To use it, install dnsmasq, and put this in the config file (usually
/etc/dnsmasq.conf)

    # forward *.epam.com requests to 10.0.0.1
    server=/epam.com/10.0.0.1
    # forward the rest to 8.8.8.8
    server=/#/8.8.8.8

You will also need to set your system dns server to point to the local dnsmasq.
This can be done by putting 127.0.0.1 in /etc/resolv.conf (and only one). There
might be cleaner ways to do this depending on your distro as resolv.conf might
be overwritten by the system each time you connect to some Wifi network for
example.

----

Alternatively, if setting up dnsmasq is too much and you don't mind hardcoding
the IP of each host used in the DFS namespace, you can simply list them in
/etc/hosts

Regarding 2)

It should be possible to mount the dfs root yes. Once you have DNS working it
should all be ok, assuming your kernel is recent enough.

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[Bug 13470] DFS mounted shares do not allow to go subdirectories

[samba-bugs]

https://bugzilla.samba.org/show_bug.cgi?id=13470

--- Comment #4 from Sergey <sergey_ilinykh@epam.com> ---
Thank you very much Aurélien.

I already played with dnsmasq this way for different purposes. I hoped there is
an easier way. But that's fine.

But mounting dfs root doesn't work for me.
Basically I take the mount line mentioned in the first post and remove MyShare.
Then I get something like following in dmesg

[95886.129233] CIFS: Attempting to mount //epam.com/
[95886.171103] CIFS VFS:  BAD_NETWORK_NAME: \\SUBDOMAINX.epam.com\epam.com
[95886.183185] CIFS VFS:  BAD_NETWORK_NAME: \\SUBDOMAINX.epam.com\epam.com
[95886.183836] CIFS VFS: cifs_mount failed w/return code = -112

Where SUBDOMAINX.epam.com is listable with smbclient -L

If I remove trailing / then I get next in dmesg

[96140.695029] CIFS VFS: Malformed UNC in devname

kernel 5.7.9

Ok. I think I need to report this under a different number.
Thanks again.

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[Bug 13470] DFS mounted shares do not allow to go subdirectories

[samba-bugs]

https://bugzilla.samba.org/show_bug.cgi?id=13470

--- Comment #5 from Sergey <sergey_ilinykh@epam.com> ---
btw I can open smb://epam.com in KDE's Dolphin. I guess it's because it doesn't
use kernel's capabilities for that.

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[Bug 13470] DFS mounted shares do not allow to go subdirectories

[samba-bugs]

https://bugzilla.samba.org/show_bug.cgi?id=13470

--- Comment #6 from Aurélien Aptel <aaptel@samba.org> ---
Can you open a new bug and attach a network trace of opening the DFS root with
Dolphin, and another trace of trying to mount the root.

See instructions here: https://wiki.samba.org/index.php/Bug_Reporting#cifs.ko

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