## File-Sharing under Linux, using Usershares – the Modernistic Way.

One concept which readers may already know, is that under Linux, we can set up a Samba-server, which makes the sharing-out of our home directories possible, and that if we fiddle with the ‘smb.conf’ configuration file thoroughly enough, it becomes possible to browse the available shares on a LAN, in a way semi-compatible with Windows computers that also reside on the same LAN.

Traditionally, this has always been a bit of a PITA, especially since the ‘/etc/samba/smb.conf’ configuration files have been finicky, and since each share practically needs to be configured individually, by a person with the ‘root’ password.

Well an alternative exists under Linux as well, which is the concept of ‘Usershares’. With this concept, each user who belongs to a specific group has the privilege, of designating a folder within his desktop manager, to share out, pointing-and-clicking. This is closer in ease-of-use, to how the process works under Windows. But, it needs to be set up correctly once, by the sysadmin, before it will work as often as simple users wish it to work.

I think that an existing Web-article on the subject, already explains well, what the settings in the ‘smb.conf’ file need to be, as well as what directories need to exist, in order for usershares to work. Except that the article I just linked to, refers to Fedora and SELinux systems and their norms. I happen to be based on Debian and KDE 4 or Plasma 5. And so I have a few observations to add:

Firstly, the following packages should be installed, under Debian also:


#apt-get install kdenetwork samba



Secondly, ‘/etc/samba/smb.conf’ needs to be edited like so:

Under Debian, the directory ‘/var/lib/samba/usershares’ already exists, If the relevant packages are installed. And its permission-bits have already been set as they should be set. Only, the feature is not configured in ‘smb.conf’ by default. And, the additional package named ‘kdenetwork-filesharing’ needs to be installed, in order for the tab to appear in Dolphin’s File-Properties box, that enables sharing from the GUI. Aside from that, enabled users need to be added to the ‘sambashare’ group, after which this membership only goes into effect, once the user in question has started a new session…

(Info Corrected 03/25/2018, 17h10,

Updated again 03/28/2018 … )

## Why visual SAMBA Browsing no longer works On My LAN.

One of the routine tasks which I recently carried out on my LAN, was to retire an old computer named ‘Walnut’. A day later I discovered that I could no longer browse my LAN, by way of my SAMBA shares. BTW, all my computers are by now either Debian / Jessie or Debian / Stretch computers. So what gives with the sudden inability to browse my shares via the GUI, which is the ‘Dolphin file browser’?

(Solved as of 03/23/2018 … )

Well in my ‘/etc/samba/smb.conf’ file, I gave the option:


[global]

(...)

smb encrypt = desired



The purpose of this was, for the Samba Server to query the Client, whether the  client supports encryption, and if affirmative, to enforce such encryption.

And, just to be sure that I haven’t made some silly mistake, I can run the following tests:


root@Phoenix:/etc/samba# cat smb.conf | grep "map to guest"
map to guest = Bad User
root@Phoenix:/etc/samba# cat smb.conf | grep "obey pam"
obey pam restrictions = no
root@Phoenix:/etc/samba#



But the disposition of the client to offer encryption, needed to be decided on the client machines, by creating a user-space file, i.e. a file in the home folder, which is named ‘~/.smb/smb.conf’, which contains the following lines:


[global]
client max protocol = SMB3



This is actually required, in order for the Dolphin / GUI-client even to offer the level of security which I wanted, which is SMB3 security. Without my specifying this, Dolphin would indicate to the Server, that SMB3 is not available, and no encryption would take place. This line of code can also be put into ‘/etc/samba/smb.conf’ , but I chose to put it into my home-folder like that.

## My router may have been flashed.

One of the ironies of my LAN is, I am hosting a Web-site from it, but I do not even own my present router. Mine is a router owned by my ISP, and which provides me with proprietary TV as well.

This means that my ISP has the right to perform a firmware update on the router, which can also be called ‘flashing the router’.

I suspect that this may have happened, around Wednesday Morning, November 9.

My main reason for suspecting this, was a subtle change in the way my router manages my LAN.

According to This Earlier Posting, I previously needed to set my router as the WINS server as well.

To explain in lay-terms what this means, I need to mention that the local IP addresses which computers have on a LAN do exist, in addition to which Windows has introduced its own way of giving the local computers names. Linux can mimic how this works, using its ‘Samba’ software suite, but also tries to avoid ‘NetBIOS’ (naming) as much as possible, outside of Samba network browsing, or ‘copying-and-pasting of files, between computers on a LAN’.

Just like domain-names need to be resolved into IP addresses on the Internet, which is the WAN to this LAN – the Wide-Area Network – on the Local Area Network, computer-names also need to be resolved into IP addresses, before the computers can actually ‘talk to each other graphically’. Traditionally, Windows offered its whimsical mechanism for doing so, which was named NetBIOS, by which any and every computer could act as the WINS server – thus offering its repository of LAN locations to the WINS clients, but alternatively, there could also exist one dedicated WINS server.

What I had grown used to, was that on my LAN, the router would insist that it be my WINS server, thus ‘not trusting’ any of my Linux boxes to do so in some way. I therefore had to defer to this service, as provided by the router.

I had previously set my ‘/etc/samba/smb.conf‘ to

   wins support = no

dns proxy = yes

Well as of Wednesday, the LAN had suddenly ‘looked different’ according to client-browsers. Each computer had suddenly remained aware only of its own identity, with no Workgroup of other computers to network with.

This was all happening, while my connection to the WAN still seemed secure and operative.

Long story short, I think that my ISP may have performed the Firmware Update, and that according to the new firmware version, the router was suddenly not willing to provide this service anymore. And so what I felt I had to do next, was change these settings back to

   wins support = no

dns proxy = no

Now that I have done so, each computer can ‘see’ my whole Workgroup again – which was apparently not feasible according to earlier experiences.

Further, for laypeople I might want to emphasize, that it is not just a frivolous exercise of mine, to give each computer a name. If they did not have names, then according to the screen-shot below, I would also not be able to tell them apart, since they all have the same icon anyway:

Now I suppose that an inquiring mind might ask, “Since Linux can imitate Windows, why does Dirk not just set ‘wins support = yes‘ as well?” My answer to this hypothetical question would be, that

• According to common sense, this option will just make the current machine available, as a potential WINS Server, but
• In my practical experience, the LAN will interpret this as more of an imperative gesture, of a kind that will actually cause a feud to break out between the machines.

In my experience, if I even set one of my Linux machines to do this, all the other Linux machines will refer to its repository of (4) LAN names, the others becoming clients, but the Windows 7 machine named ‘Mithral’ will refuse to have it. In this case, Mithral will insist that it must be the WINS Server, and not some Linux box. And then, further logic-testing of which machines can see which, will reveal that in practice, I must leave this option switched off, if there is also to be any Windows machine to share the LAN with.

Dirk

## RTL8723BE WiFi Stable Under Linux

On the laptop I name ‘Klystron’, I have kernel version ‘‘, and the misfortune of a WiFi chip-set that uses the kernel module ‘‘ with its companion kernel modules. Fortunately, I believe that it finally, fully stable!

I think that the most important detail on my part to getting this kernel module stable, was to add the file ‘‘ to contain the following code:


options rtl8723be fwlps=0
options rtl8723be swlps=0




Yet, as a series of blog postings already shows, it was not so quick and easy to obtain stability. One reason I think that my WiFi was failing on me recently, was my persistence in trying to put the laptop to Sleep, aka “Suspend To RAM”. This was never fully supported, and after Resuming from this sort of suspend mode, the WiFi would always be unstable. The only way I had to remedy this, was to change my user-level configuration, never to put the laptop to Sleep again.

Even with the WiFi supposedly stable in this way, the malfunction remains, that for any duration of time I close the laptop lid, the WiFi temporarily cuts off, which I think is a problem with the antenna. My solution: Leave the laptop idling, with its lid open. The result: Days and days of steady connection. Some small amount of dust on the laptop keyboard.

But there seemed to have been another problem with my WiFi specifically. The modem-router which I rent from Bell seems to have a specific policy. It sets itself to be the DNS server for my LAN, which downloads the IP addresses from its DNS parent. The WiFi router seems to have a zero-tolerance policy, if any computers try to bypass it as my DNS server. And this problem can be so strict, that even to have my LAN machines act as server, will cause problems and stability issues, which mimic hardware WiFi disconnection issues.

In my ‘‘, I needed to set


wins support = no

dns proxy = yes




Otherwise, the member servers would fail to see each other as Samba-connected, and finally lose their connection altogether.

Further, I had scripted the idea into my configuration files, to prepend IP address 8.8.8.8 as an additional DNS server into ‘‘ on boot-up, just hoping to obtain wider connectivity. But then one additional problem with that was, that this public DNS server would suggest IPv6 addresses in addition to IPv4, and that even though my user-level settings for the network said to ignore IPv6 addresses, a malfunction in the kernel – which has not bee remedied – would cause the WiFi client to try to request the IPv6 addresses anyway. My user-level settings were being ignored.

Thus, I think that getting rid of the 8.8.8.8 was instrumental in achieving stability.  Since this router does not tolerate IPv6, and since it is now my only DNS server, there is no risk of IPv6 addresses ever getting mentioned on my LAN.

On that note: It is normal on a dual-stack machine, for each NIC to have an IPv4 as well as a local, “Link” IPv6 address. But I think that one aspect in which the behavior of Ethernet cards is different from WiFi, is that the Ethernet card will not try to use its IPv6 address, because that will recognize this is not a global address, which would need to be assigned by the router. It would only try to use its “link” IPv6, if it was to try to connect directly to another machine on my LAN. OTOH, It would seem that a WiFi chip-set will not recognize that its IPv6 is invalid, and will ask for “Global” IPv6 addresses.

This can be an embarrassment, if the router did not specify any, and if the router assumes that it is the only DNS server.

Dirk