Ben Opp's questions

I cannot access the office Synology NAS from one of the clients on the network, using Windows Explorer. When I click its icon in the Network section, I get an error:

"Couldn't access \\SynologyNAS" "Error 0x80070035. Network path not found"

Windows problem diagnosis actually doesn't find any problems.

However, all other applications can locate the SMB shares:

• This NAS is accessible through Win Explorer from every other client on the local network.

• From this Windows workstation, the Synology Drive Client app, as well as Synology Assistant can access and use it.

• Going to the NAS's IP in the browser from this machine, it's accessible.

Only Windows Explorer is not getting through from this machine. It's important for users to be able to do that (it's also the only way they know how). Here is the output of some diagnostic commands suggested in Synology forums:

PS C:\WINDOWS\system32> nbtstat -r

  Statistik zur NetBIOS-Namensauflösung und -Registrierung
------------------------------------------------------------------

  Durch Broadcast aufgelöst    = 11
  Durch Namenserver aufgelöst   = 0
  Durch Broadcast registriert   = 27
  Durch Namenserver registriert = 0
  Durch Broadcast aufgelöste NetBIOS-Namen
--------------------------------------------------
ZENTRUMLG
ZENTRUMLG <00>
FALKELGD-LE
FALKELGD-LE
ZENTRUMLG <00>
ZENTRUMLG
FALKELGD-LE
ZENTRUMLG <00>
PS C:\WINDOWS\system32> nbtstat -A 192.168.0.3

Ethernet:
Knoten-IP-Adresse: [192.168.0.52] Bereichskennung: []

    NetBIOS-Namentabelle des Remotecomputers
     Name               Typ          Status
  ---------------------------------------------
  ZENTRUMLG      <00>  EINDEUTIG   Registriert
  ZENTRUMLG      <03>  EINDEUTIG   Registriert
  ZENTRUMLG      <20>  EINDEUTIG   Registriert
  WORKGROUP      <00>  GRUPPE      Registriert
  WORKGROUP      <1E>  GRUPPE      Registriert
  MAC Adresse = 00-00-00-00-00-00
PS C:\WINDOWS\system32> nbtstat -a ZentrumLG

Ethernet:
Knoten-IP-Adresse: [192.168.0.52] Bereichskennung: []

    NetBIOS-Namentabelle des Remotecomputers
     Name               Typ          Status
  ---------------------------------------------
  ZENTRUMLG      <00>  EINDEUTIG   Registriert
  ZENTRUMLG      <03>  EINDEUTIG   Registriert
  ZENTRUMLG      <20>  EINDEUTIG   Registriert
  WORKGROUP      <00>  GRUPPE      Registriert
  WORKGROUP      <1E>  GRUPPE      Registriert
  MAC Adresse = 00-00-00-00-00-00

I administer a network of 10 workstations for a small non-profit (also, I'm very inexperienced, forgive me if it's a silly question), and everything has been managed so far as if they were home PCs used by multiple persons, on some workstations a handful of employees even share a single user.

I'm considering introducing Active Directory for managing the user accounts, but we currently don't have a Windows server. A couple of Synology disk stations have been bought, and I'm wondering if I can deploy AD on it? Or is a Windows Server OS necessary for that?

Search results I've found all speak of "integrating" a Linux server or disk station into an AD domain, not using it as a domain controller.

I have Tiki 15.4 running on a shared host - I have a problem with the file galleries feature: Uploading stuff to the file galleries works well, for instance I uploaded a .webm video and then it's listed by the wiki interface as present in the gallery. However I cannot not download or do anyhting else with this or any other files later on.

I get an “unable to acces file” error for all my file galleries when trying to download. I can reproduce this for all new uploads.

How can I diagnose what’s happening? I tried these things:

1. tiki-syslog.php only logged my admin login/logout.
2. I activated recording and showing for all file archives/file events and generated an action report. Here it shows that I downloaded files, but nothing about errors/failures.
3. I checked the database in PHPmyadmin, all tables result ok.

EDIT:

4. I also enabled debug mode, the php messages I'm getting seem to be non-critical, i.e. they shouldn't hint at something that impairs functionality.

EDIT 2: There may be a problem with permissions to access the folder where the files should be saved. Tiki has two options for file galleries: they can be saved either in a web directory or in the database. At setup, I chose to save them in a directory. Tiki documentation says, this directory should not be directly accessible. This can be accomplished in two ways:

• Use a directory outside your webserver document root, make sure your php script can read and write to that directory
• Use a directory inside the document root and use .htaccess to prevent the user from listing the directory contents

The folder I specified is inside the DocumentRoot (I think), i.e. it is under Tiki's root directory: tiki-15.4/files, so I believe PHP should have permission to read/write there. I made no changes to the permissions, and I'm not sure if I even can (or how) on this shared host.

Current permissions are:

e42604@web06:~$ ls -ld html/apps/tiki-15.4/files
drwxr-xr-x 4 e42604 e42604 4096 Jan 21  2017 html/apps/tiki-15.4/files

e42604 is my ssh user. I don't know if it's identical to the web server user, but I guess it should be, yes?

These are the permissions on the web root:

e42604@web06:~$ ls -ld      
drwxr-x--- 13 e42604 www-data 4096 Jan  3 21:09 .

I checked the folder I specified to upload all files to (tiki-15.4/files) through FTP, and it did not contain the files I had uploaded, although they were all listed as being there in the wiki interface.

However, when I choose to store file galleries in the database, it works: I can upload stuff and download it again.

I could just go with this as a solution, but I'd prefer finding out how to store the files in a web folder.

Ok, so normally, a server provides a webdav share, and that can be accessed by mounting it on some other computer. What I want to do is to mount it (permanently) not elsewhere, but on the actual Ubuntu server that is providing it. My questions:

1. Is it possible?

   1.a if yes, how is it done properly?

2. Is it safe?

I have already tried it by inserting the following line into /etc/fstab (of the server): https://my.example.com/remote.php/webdav /home/ben/owncloud davfs auto,uid=ben,gid=ben,-netdev,rw 0 0

This isn't working as intended, because at startup, it turns out to be not mounted, and it says only root can mount, EDIT: exactly every other time I reboot. Also, last time I was experimenting with the options, chaos ensued and the server went down for a while (but maybe for a completely unrelated reason), so now I'm afraid to try again until I gather some more information... To elaborate why I'm doing this: What I'm trying is to upload files from my phone to the server's webdav via rsync. However, I cannot mount the webdav on my phone, - hence, the idea to mount it on the server itself.

if I want to transfer files to a webdav share, can I do that directly to the server that the share originates from, or does it need to be mounted on the machine that I send the rsync to? The thing is, I sort of can't mount that webdav share anywhere, but it's accessible through a browser. That'll let me download things, but not upload via rsync. So I'm wondering, can I get rsync to put things on the webdav share while it isn't mounted anywhere? I figure authentication might be a problem, because afaik rsync uses the ssh protocol, so how can I make it authenticate to webdav?

This question is about Apache crashing repeatedly, and while it runs, it's unresponsive, i.e. I can't reach the site, so I'm trying to figure out the reason why.

My Owncloud site served by Apache 2.4.7 on Ubuntu 14.04 is not reachable. To check what's wrong, I ran apachectl -S:

~$ sudo apachectl -S
AH00558: apache2: Could not reliably determine the server's fully qualified domain name, using 127.0.1.1. Set the 'ServerName' directive globally to suppress this message
VirtualHost configuration:
*:443                  oc.benopp.org (/etc/apache2/sites-enabled/000-default.conf:1)
*:80                   127.0.1.1 (/etc/apache2/sites-enabled/000-default.conf:18)
ServerRoot: "/etc/apache2"
Main DocumentRoot: "/var/www"
Main ErrorLog: "/var/log/apache2/error.log"
Mutex mpm-accept: using_defaults
Mutex watchdog-callback: using_defaults
Mutex rewrite-map: using_defaults
Mutex ssl-stapling: using_defaults
Mutex ssl-cache: using_defaults
Mutex default: dir="/var/lock/apache2" mechanism=fcntl 
PidFile: "/var/run/apache2/apache2.pid"
Define: DUMP_VHOSTS
Define: DUMP_RUN_CFG
User: name="www-data" id=33
Group: name="www-data" id=33

This doesn't seem to explain the problem though. The error.log says this:

[Wed Jan 07 19:07:13.384687 2015] [ssl:warn] [pid 1699] AH01906: RSA server certificate is a CA certificate (BasicConstraints: CA == TRUE !?)
[Wed Jan 07 19:07:13.389319 2015] [mpm_prefork:notice] [pid 1699] AH00163: Apache/2.4.7 (Ubuntu) mod_gnutls/0.5.10 PHP/5.5.9-1ubuntu4.5 OpenSSL/1.0.1f configured -- resuming normal operations
[Wed Jan 07 19:07:13.389359 2015] [core:notice] [pid 1699] AH00094: Command line: '/usr/sbin/apache2'
[Wed Jan 07 19:08:01.788631 2015] [mpm_prefork:error] [pid 1699] AH00161: server reached MaxRequestWorkers setting, consider raising the MaxRequestWorkers setting

I don't understand how the Max requests settings can be reached with only me using the site. Am I right in assuming that while I'm the only one trying to access Owncloud to download some files or change settings, that should never cause this amount of requests?

To take a closer look, I activated mod_status. Unfortunately I don't know what to make of the readout, because I only taught myself how to setup Apache to run my Owncloud, and I'm new to this. It seems a bit long to post the server-status page readout here inline, so I made a paste: http://pastie.org/private/aj7zduzhrt8sayjb4hncg

So, all the processes are "sending reply", except I don't know to what, because I'm not sending any requests, and the server is actually disconnected from the internet right now. In the documentation it is explained how to look for problems that are causing excessive workloads, but I'm having trouble getting Top to show me something I can use. It does seem though that CPU-load really isn't it, there are no high loads to be seen. Can you tell what the problem is from this readout?

EDIT2: another crash happened a few hours ago, here's a part that seems relevant from the error.log:

beginning of file:

ProblemType: Crash
Architecture: amd64
CrashCounter: 1
Date: Tue Jan  6 13:50:05 2015
DistroRelease: Ubuntu 14.04
ExecutablePath: /usr/sbin/apache2
ExecutableTimestamp: 1406039884
ProcCmdline: /usr/sbin/apache2 -k start
ProcCwd: /etc/apache2
ProcEnviron:
 PATH=(custom, no user)
 LANG=C
ProcMaps:
 7fd2a4000000-7fd2a8000000 rw-s 00000000 00:04 12964                      /dev/zero (deleted)
 7fd2a8000000-7fd2a8021000 rw-p 00000000 00:00 0 
 7fd2a8021000-7fd2ac000000 ---p 00000000 00:00 0 
 7fd2aced8000-7fd2acedd000 r-xp 00000000 08:01 266060                     /lib/x86_64-linux-gnu/libnss_dns-2.19.so
 7fd2acedd000-7fd2ad0dc000 ---p 00005000 08:01 266060                     /lib/x86_64-linux-gnu/libnss_dns-2.19.so
 7fd2ad0dc000-7fd2ad0dd000 r--p 00004000 08:01 266060                     /lib/x86_64-linux-gnu/libnss_dns-2.19.so

and so on and so on, until end of file:

ProcStatus:
 Name:  apache2
 State: R (running)
 Tgid:  2807
 Ngid:  0
 Pid:   2807
 PPid:  1838
 TracerPid: 0
 Uid:   33  33  33  33
 Gid:   33  33  33  33
 FDSize:    64
 Groups:    33 
 VmPeak:      525052 kB
 VmSize:      524944 kB
 VmLck:        0 kB
 VmPin:        0 kB
 VmHWM:    23680 kB
 VmRSS:    23680 kB
 VmData:       85112 kB
 VmStk:      136 kB
 VmExe:      592 kB
 VmLib:    74868 kB
 VmPTE:      712 kB
 VmSwap:           0 kB
 Threads:   1
 SigQ:  1/29106
 SigPnd:    0000000000000000
 ShdPnd:    0000000000000000
 SigBlk:    0000000000004000
 SigIgn:    0000000001001000
 SigCgt:    000000018c0042eb
 CapInh:    0000000000000000
 CapPrm:    0000000000000000
 CapEff:    0000000000000000
 CapBnd:    0000001fffffffff
 Seccomp:   0
 Cpus_allowed:  3
 Cpus_allowed_list: 0-1
 Mems_allowed:  00000000,00000001
 Mems_allowed_list: 0
 voluntary_ctxt_switches:   21
 nonvoluntary_ctxt_switches:    34
Signal: 11
Uname: Linux 3.13.0-43-generic x86_64
UserGroups: 
CoreDump: base64

then the CoreDump I deleted.