Posts Tagged ‘make’

Deny DHCP Address by MAC on Linux

Thursday, October 8th, 2020

Deny DHCP addresses by MAC ignore MAC to not be DHCPD leased on GNU / Linux howto

I have not blogged for a long time due to being on a few weeks vacation and being in home with a small cute baby. However as a hardcore and a bit of dumb System administrator, I have spend some of my vacation and   worked on bringing up the the and the other Websites hosted as a high availvailability ones living on a 2 Webservers running on a Master to Master MySQL Replication backend database, this is oll hosted on  servers, set to run as a round robin DNS hosts on 2 servers one old Lenove ThinkCentre Edge71 as well as a brand new real Lenovo server Lenovo ThinkServer SD350 with 24 CPUs and a 32 GB of RAM
To assure Internet Connectivity is having a good degree of connectivity and ensure websites hosted on both machines is not going to die if one of the 2 pair configured Fiber Optics Internet Providers Bergon.NET has some Issues, I've rented another Internet Provider Line is set bought from the VIVACOM Mobile Fiber Internet provider – that is a 1 Gigabit Fiber Optics Line.
Next to that to guarantee there is no Database, Webserver, MailServer, Memcached and other running services did not hit downtimes due to Electricity power outage, two Powerful Uninterruptable Power Supplies (UPS)  FPS Fortron devices are connected to the servers each of which that could keep the machine and the connected switches and Servers for up to 1 Hour.

The machines are configured to use dhcpd to distributed IP addresses and the Main Node is set to distribute IPs, however as there is a local LAN network with more of a personal Work PCs, Wireless Devices and Testing Computers and few Virtual machines in the Network and the IPs are being distributed in a consequential manner via a ISC DHCP server.

As always to make everything work properly hence, I had again some a bit weird non-standard requirement to make some of the computers within the Network with Static IP addresses and the others to have their IPs received via the DHCP (Dynamic Host Configuration Protocol) and add some filter for some of the Machine MAC Addresses which are configured to have a static IP addresses to prevent the DHCP (daemon) server to automatically reassign IPs to this machines.

After a bit of googling and pondering I've done it and some of the machines, therefore to save others the efforts to look around How to set Certain Computers / Servers Network Card MAC (Interfaces) MAC Addresses  configured on the LAN network to use Static IPs and instruct the DHCP server to ingnore any broadcast IP addresses leases – if they're to be destined to a set of IGNORED MAcs, I came up with this small article.

Here is the DHCP server /etc/dhcpd/dhcpd.conf from my Debian GNU / Linux (Buster) 10.4


option domain-name "pcfreak.lan";
option domain-name-servers,,,;
max-lease-time 891200;
class "black-hole" {
    match substring (hardware, 1, 6);
    ignore booting;
subclass "black-hole" 18:45:91:c3:d9:00;
subclass "black-hole" 70:e2:81:13:44:11;
subclass "black-hole" 70:e2:81:13:44:12;
subclass "black-hole" 00:16:3f:53:5d:11;
subclass "black-hole" 18:45:9b:c6:d9:00;
subclass "black-hole" 16:45:93:c3:d9:09;
subclass "black-hole" 16:45:94:c3:d9:0d;/etc/dhcpd/dhcpd.conf
subclass "black-hole" 60:67:21:3c:20:ec;
subclass "black-hole" 60:67:20:5c:20:ed;
subclass "black-hole" 00:16:3e:0f:48:04;
subclass "black-hole" 00:16:3e:3a:f4:fc;
subclass "black-hole" 50:d4:f5:13:e8:ba;
subclass "black-hole" 50:d4:f5:13:e8:bb;
subnet netmask {
        option routers        ;
        option subnet-mask    ;
host think-server {
        hardware ethernet 70:e2:85:13:44:12;
default-lease-time 691200;
max-lease-time 891200;
log-facility local7;

To spend you copy paste efforts a file with Deny DHCP Address by Mac Linux configuration is here
Of course I have dumped the MAC Addresses to omit a data leaking but I guess the idea behind the MAC ADDR ignore is quite clear

The main configuration doing the trick to ignore a certain MAC ALenovo ThinkServer SD350ddresses that are reachable on the Connected hardware switch on the device is like so:

class "black-hole" {
    match substring (hardware, 1, 6);
    ignore booting;
subclass "black-hole" 18:45:91:c3:d9:00;

The Deny DHCP Address by MAC is described on distribution lists here but it seems the documentation on the topic on how to Deny / IGNORE DHCP Addresses by MAC Address on Linux has been quite obscure and limited online.

As you can see in above config the time via which an IP is freed up and a new IP lease is done from the server is severely maximized as often DHCP servers do use a max-lease-time like 1 hour (3600) seconds:, the reason for increasing the lease time to be to like 10 days time is that the IPs in my network change very rarely so it is a waste of CPU cycles to do a frequent lease.

default-lease-time 691200;
max-lease-time 891200;

As you see to Guarantee resolving works always as expected I have configured – Google Public DNS and OpenDNS IPs

option domain-name-servers,,,;

One hint to make is, after setting up all my desired config in the standard config location /etc/dhcp/dhcpd.conf it is always good idea to test configuration before reloading the running dhcpd process.


root@pcfreak: ~# /usr/sbin/dhcpd -t
Internet Systems Consortium DHCP Server 4.4.1
Copyright 2004-2018 Internet Systems Consortium.
All rights reserved.
For info, please visit
Config file: /etc/dhcp/dhcpd.conf
Database file: /va/home/hipo/infor/lib/dhcp/dhcpd.leases
PID file: /var/run/

That's all folks with this sample config the IPs under subclass "black-hole", which are a local LAN Static IP Addresses will never be offered leasess anymore from the ISC DHCP.
Hope this stuff helps someone, enjoy and in case if you need a colocation of a server or a website hosting for a really cheap price on this new set High Availlability up described machines open an inquiry on


Rsync copy files with root privileges between servers with root superuser account disabled

Tuesday, December 3rd, 2019



Sometimes on servers that follow high security standards in companies following PCI Security (Payment Card Data Security) standards it is necessery to have a very weird configurations on servers,to be able to do trivial things such as syncing files between servers with root privileges in a weird manners.This is the case for example if due to security policies you have disabled root user logins via ssh server and you still need to synchronize files in directories such as lets say /etc , /usr/local/etc/ /var/ with root:root user and group belongings.

Disabling root user logins in sshd is controlled by a variable in /etc/ssh/sshd_config that on most default Linux OS
installations is switched on, e.g. 

grep -i permitrootlogin /etc/ssh/sshd_config
PermitRootLogin yes

Many corporations use Vulnerability Scanners such as Qualys are always having in their list of remote server scan for SSH Port 22 to turn have the PermitRootLogin stopped with:


PermitRootLogin no

In this article, I'll explain a scenario where we have synchronization between 2 or more servers Server A / Server B, whatever number of servers that have already turned off this value, but still need to
synchronize traditionally owned and allowed to write directories only by root superuser, here is 4 easy steps to acheive it.


1. Add rsyncuser to Source Server (Server A) and Destination (Server B)

a. Execute on Src Host:


groupadd rsyncuser
useradd -g 1000 -c 'Rsync user to sync files as root src_host' -d /home/rsyncuser -m rsyncuser


b. Execute on Dst Host:


groupadd rsyncuser
useradd -g 1000 -c 'Rsync user to sync files dst_host' -d /home/rsyncuser -m rsyncuser


2. Generate RSA SSH Key pair to be used for passwordless authentication

a. On Src Host

su – rsyncuser

ssh-keygen -t rsa -b 4096


b. Check .ssh/ generated key pairs and make sure the directory content look like.


[rsyncuser@src-host .ssh]$ cd ~/.ssh/;  ls -1



3. Copy to Destination host server under authorized_keys


scp ~/.ssh/  rsyncuser@dst-host:~/.ssh/authorized_keys


Next fix permissions of authorized_keys file for rsyncuser as anyone who have access to that file (that exists as a user account) on the system
could steal the key and use it to run rsync commands and overwrite remotely files, like overwrite /etc/passwd /etc/shadow files with his custom crafted credentials
and hence hack you 🙂

Hence, On Destionation Host Server B fix permissions with:

su – rsyncuser; chmod 0600 ~/.ssh/authorized_keys
[rsyncuser@dst-host ~]$


For improved security here to restrict rsyncuser to be able to run only specific command such as very specific script instead of being able to run any command it is good to use little known command= option
once creating the authorized_keys


4. Test ssh passwordless authentication works correctly

For that Run as a normal ssh from rsyncuser

On Src Host


[rsyncuser@src-host ~]$ ssh rsyncuser@dst-host

Perhaps here is time that for those who, think enabling a passwordless authentication is not enough secure and prefer to authorize rsyncuser via a password red from a secured file take a look in my prior article how to login to remote server with password provided from command line as a script argument / Running same commands on many servers 

5. Enable rsync in sudoers to be able to execute as root superuser (copy files as root)


For this step you will need to have sudo package installed on the Linux server.

Then, Execute once logged in as root on Destionation Server (Server B)


[root@dst-host ~]# grep 'rsyncuser ALL' /etc/sudoers|wc -l || echo ‘rsyncuser ALL=NOPASSWD:/usr/bin/rsync’ >> /etc/sudoers


Note that using rsync with a ALL=NOPASSWD in /etc/sudoers could pose a high security risk for the system as anyone authorized to run as rsyncuser is able to overwrite and
respectivle nullify important files on Destionation Host Server B and hence easily mess the system, even shell script bugs could produce a mess, thus perhaps a better solution to the problem
to copy files with root privileges with the root account disabled is to rsync as normal user somewhere on Dst_host and use some kind of additional script running on Dst_host via lets say cron job and
will copy gently files on selective basis.

Perhaps, even a better solution would be if instead of granting ALL=NOPASSWD:/usr/bin/rsync in /etc/sudoers is to do ALL=NOPASSWD:/usr/local/bin/
that will get triggered, once the files are copied with a regular rsyncuser acct.


6. Test rsync passwordless authentication copy with superuser works

Do some simple copy, lets say copy files on Encrypted tunnel configurations located under some directory in /etc/stunnel on Server A to /etc/stunnel on Server B

The general command to test is like so:

rsync -aPz -e 'ssh' '–rsync-path=sudo rsync' /var/log rsyncuser@$dst_host:/root/tmp/

This will copy /var/log files to /root/tmp, you will get a success messages for the copy and the files will be at destination folder if succesful.


On Src_Host run:


[rsyncuser@src-host ~]$ dst=FQDN-DST-HOST; user=rsyncuser; src_dir=/etc/stunnel; dst_dir=/root/tmp;  rsync -aP -e 'ssh' '–rsync-path=sudo rsync' $src_dir  $rsyncuser@$dst:$dst_dir;


7. Copying files with root credentials via script

The simlest file to use to copy a bunch of predefined files  is best to be handled by some shell script, the most simple version of it, could look something like this.

# On server1 use something like this
# On server2 dst server
# add in /etc/sudoers
# rsyncuser ALL=NOPASSWD:/usr/bin/rsync




for i in $(echo ${src[@]}); do
rsync -aPvz –delete –dry-run -e 'ssh' '–rsync-path=sudo rsync' "$i" $rsyncuser@$dst_host:$dst_dir"$i";

In above script as you can see, we define a bunch of files that will be copied in bash array and then run a loop to take each of them and copy to testination dir.
A very sample version of the script 


Lets do short overview on what we have done here. First Created rsyncuser on SRC Server A and DST Server B, set up the key pair on both copied the keys to make passwordless login possible,
set-up rsync to be able to write as root on Dst_Host / testing all the setup and pinpointing a small script that can be used as a backbone to develop something more complex
to sync backups or keep system configurations identicatial – for example if you have doubts that some user might by mistake change a config etc.
In short it was pointed the security downsides of using rsync NOPASSWD via /etc/sudoers and few ideas given that could be used to work on if you target even higher
PCI standards.


Fix FTP active connection issues “Cannot create a data connection: No route to host” on ProFTPD Linux dedicated server

Tuesday, October 1st, 2019


Earlier I've blogged about an encounter problem that prevented Active mode FTP connections on CentOS
As I'm working for a client building a brand new dedicated server purchased from Contabo Dedi Host provider on a freshly installed Debian 10 GNU / Linux, I've had to configure a new FTP server, since some time I prefer to use Proftpd instead of VSFTPD because in my opinion it is more lightweight and hence better choice for a small UNIX server setups. During this once again I've encounted the same ACTIVE FTP not working from FTP server to FTP client host machine. But before shortly explaining, the fix I find worthy to explain briefly what is ACTIVE / PASSIVE FTP connection.


1. What is ACTIVE / PASSIVE FTP connection?

Whether in active mode, the client specifies which client-side port the data channel has been opened and the server starts the connection. Or in other words the default FTP client communication for historical reasons is in ACTIVE MODE. E.g.
Client once connected to Server tells the server to open extra port or ports locally via which the overall FTP data transfer will be occuring. In the early days of networking when FTP protocol was developed security was not of such a big concern and usually Networks did not have firewalls at all and the FTP DATA transfer host machine was running just a single FTP-server and nothing more in this, early days when FTP was not even used over the Internet and FTP DATA transfers happened on local networks, this was not a problem at all.

In passive mode, the server decides which server-side port the client should connect to. Then the client starts the connection to the specified port.

But with the ever increasing complexity of Internet / Networks and the ever tightening firewalls due to viruses and worms that are trying to own and exploit networks creating unnecessery bulk loads this has changed …


2. Installing and configure ProFTPD server Public ServerName

I've installed the server with the common cmd:


apt –yes install proftpd


And the only configuration changed in default configuration file /etc/proftpd/proftpd.conf  was
ServerName          "Debian"

I do this in new FTP setups for the logical reason to prevent the multiple FTP Vulnerability Scan script kiddie Crawlers to know the exact OS version of the server, so this was changed to:


ServerName "MyServerHostname"


Though this is the bad security through obscurity practice doing so is a good practice.

3. Create iptable firewall rules to allow ACTIVE FTP mode

But anyways, next step was to configure the firewall to be allowed to communicate on TCP PORT 21 and 20 to incoming source ports range 1024:65535 (to enable ACTIVE FTP) on firewal level with iptables on INPUT and OUTPUT chain rules, like this:


iptables -A INPUT -p tcp –sport 1024:65535 -d 0/0 –dport 21 -m state –state NEW,ESTABLISHED -j ACCEPT
iptables -A INPUT -p tcp -s 0/0 –sport 1024:65535 -d 0/0 –dport 20 -m state –state NEW,ESTABLISHED -j ACCEPT
iptables -A OUTPUT -p tcp -s 0/0 –sport 21 -d 0/0 –dport 1024:65535 -m state –state ESTABLISHED -j ACCEPT
iptables -A OUTPUT -p tcp -s 0/0 –sport 20 -d 0/0 –dport 1024:65535 -m state –state ESTABLISHED,RELATED -j ACCEPT

Talking about Active and Passive FTP connections perhaps for novice Linux users it might be worthy to say few words on Active and Passive FTP connections

Once firewall has enabled FTP Active / Passive connections is on and FTP server is listening, to test all is properly configured check iptable rules and FTP listener:

/sbin/iptables -L INPUT |grep ftp
ACCEPT     tcp  —  anywhere             anywhere             tcp spts:1024:65535 dpt:ftp state NEW,ESTABLISHED
ACCEPT     tcp  —  anywhere             anywhere             tcp spts:1024:65535 dpt:ftp-data state NEW,ESTABLISHED
ACCEPT     tcp  —  anywhere             anywhere             tcp dpt:ftp
ACCEPT     tcp  —  anywhere             anywhere             tcp dpt:ftp-data

netstat -l | grep "ftp"
tcp6       0      0 [::]:ftp                [::]:*                  LISTEN    


4. Loading nf_nat_ftp module and net.netfilter.nf_conntrack_helper (for backward compitability)

Next step of course was to add the necessery modules nf_nat_ftp nf_conntrack_sane that makes FTP to properly forward ports with respective Firewall states on any of above source ports which are usually allowed by firewalls, note that the range of ports given 1024:65535 might be too much liberal for paranoid sysadmins and in many cases if ports are not filtered, if you are a security freak you can use some smaller range such as 60000-65535.


Here is time to say for sysadmins who haven't recently had a task to configure a new (unecrypted) File Transfer Server as today Secure FTP is almost alltime used for file transfers for the sake of security might be puzzled to find out the old Linux kernel ip_conntrack_ftp which was the standard module used to make FTP Active connections work is substituted nowadays with  nf_nat_ftp and nf_conntrack_sane.

To make the 2 modules permanently loaded on next boot on Debian Linux they have to be added to /etc/modules

Here is how sample /etc/modules that loads the modules on next system boot looks like

cat /etc/modules
# /etc/modules: kernel modules to load at boot time.
# This file contains the names of kernel modules that should be loaded
# at boot time, one per line. Lines beginning with "#" are ignored.

Next to say is that in newer Linux kernels 3.x / 4.x / 5.x the nf_nat_ftp and nf_conntrack-sane behaviour changed so  simply loading the modules would not work and if you do the stupidity to test it with some FTP client (I used gFTP / ncftp from my Linux desktop ) you are about to get FTP No route to host errors like:


Cannot create a data connection: No route to host



Sometimes, instead of No route to host error the error FTP client might return is:


227 entering passive mode FTP connect connection timed out error

To make the nf_nat_ftp module on newer Linux kernels hence you have to enable backwards compatibility Kernel variable





echo 1 > /proc/sys/net/netfilter/nf_conntrack_helper


To make it permanent if you have enabled /etc/rc.local legacy one single file boot place as I do on servers – for how to enable rc.local on newer Linuxes check here

or alternatively add it to load via sysctl

sysctl -w net.netfilter.nf_conntrack_helper=1

And to make change permanent (e.g. be loaded on next boot)

echo 'net.netfilter.nf_conntrack_helper=1' >> /etc/sysctl.conf


5. Enable PassivePorts in ProFTPD or PassivePortRange in PureFTPD

Last but not least open /etc/proftpd/proftpd.conf find PassivePorts config value (commented by default) and besides it add the following line:


PassivePorts 60000 65534


Just for information if instead of ProFTPd you experience the error on PureFTPD the configuration value to set in /etc/pure-ftpd.conf is:

PassivePortRange 30000 35000

That's all folks, give the ncftp / lftp / filezilla or whatever FTP client you prefer and test it the FTP client should be able to talk as expected to remote server in ACTIVE FTP mode (and the auto passive mode) will be not triggered anymore, nor you will get a strange errors and failure to connect in FTP clients as gftp.

Cheers 🙂

How to make Samba smbfs / cifs mount share location with user / pass credentials authenticate via file stored credentials

Friday, July 19th, 2019

That's pretty trivial and perhaps if you had to manage samba server or cifs on a Linux host you already know it but for beginners, that might be interesting.

So in this short article I will explain how to make configure smbfs / cifs authentication from Linux host A client to Linux host B server running smbd and nmbd samba server (which is the smfs / cifs share server) by using external authentication file for either mount command or if /etc/fstab used to automatically authenticate using a preconfigured mount saba share via /etc/fstab.

Before you start to do anything with samba on Linux host A client machine, you will need as a minimum to have installed cifs-utils or smbfs (assuming you're on Debian Linux like you can check with dpkg -l and if missing install it via:



apt-get install cifs-utils


Or on older systems or for smbfs support


apt-get install smbfs


The general mount smbfs share command without specified external credentials file would look like so:


mount //mynetworksharename/ /shares/data -o username=myusername, password=mypassword

So how to use external auth file to prevent samba shares  users and passwords to not be stored in root user history all the time?

To do so it is pretty straight forward all you need to do is to create a single user / pass credentials variable defined lets say to file called .smbcredentials or .cifs under some directory lets /root/.smbcredentials.

One note here is (many people prefer to store the password under /root) for security reasons as root directory is usually readable only by administrator and would prevent a non-privileged user to read the user / pass which are stored in plain text.

.smbcredentials is described in mount.cifs man page, here is what it says about credentials variable understood by mount / mount.cifs command  file syntax:


    specifies a file that contains a username and/or password. The format of the file is:


For a CIFS (Common Internet File System) which is a new implementation of old Windows Share (SMB protocol) avaiable in newer Windows XP / 7 / 10 machines, to do the cifs mount manually:

mount -v -t cifs //WINSHARESERVER/topsecretfiles /mnt/network/ -o credentials=/mnt/creds-file

or use 


mount.cifs //WINSSHARE/topsecretfiles /mnt/network/ -o credentials=/root/.creds-file


For old smbfs protocol for backward compatibility so older Win 2000 or Winblows server XP PCs configured to also access the Linux samba mount.

mount -t smbfs //WINHARESERVER/topsecretfiles /mnt/network/ -o credentials=/mnt/.smbcredentials

Once you have the defined .smbcredentials file name, be sure to also protect it with properly set permissions like 0600 (rw) readable only for root user. 

chmod 0600 /root/.smbcredentials

Note that in that example .smbcredentials is set to be a hidden file on purpose as this is a hidden file it will make it slightly less seenable if introduder breaks on the server (an example of security through obscurity)


Next lets see how to mount the Windows Samba Share permanently with predefined user / pass server login

For many non secured Windows shares one can use /etc/fstab line definition as simple as:

//server-share-name/sharename  /mnt/shares/sharename  cifs  guest,uid=1000,iocharset=utf8  0

For password protected Win Share mounts however, the simplest way to do is via /etc/fstab line add like so:




//servername/sharename  /mnt/shares/sharename  cifs  username=msusername,password=mspassword,iocharset=utf8,sec=ntlm  0  0

Note that the sec=ntlm is optional and remote samba server or Windows Share server version has to support this kind of authentication and in some cases you could safely reove sec=ntlm, just use it, when you know what you're doing. iocharset is good to have as for Russian / Bulgarian e.g.  Cyrillic, Chineese, Indian and other exotic languages and other strange language encoding to be supported and properly shown on the mounted share it should be properly defined …, 

A good permissions would be:

chmod 600 ~/.smbcredentials

To use the external /root/.smbcredentials password it shold be like so:








# cat /root/.smbcredentials




Finally /root/.smbcredentials record should be as so:

//share-server-name/sharename /mnt/shares/windowsshare cifs credentials=/home/ubuntuusername/.smbcredentials,iocharset=utf8,sec=ntlm 0 0

Note You should already have

/mnt/shares/windowshare created on server B (the ount client) with:

mkdir -p  /mnt/shares/windowshare

To mount /etc/fstab defined filesystem to mount on next server boot then do

mount /mnt/shares/windowshare

or completely mount / remount all present /etc/fstab filesystems with the common

mount -a

(but here be careful as this might cause you troubles already other NFS or whatever FS is mounted and being read by clients) :

And you the remote Samba Share (mount location) – should be reachable with ping command and traceroute and remote server ports 139, 445 etc. should be up running opened and connectable from server B share-server-name/sharename

If you face some issues when trying to mount remote share with mount -t smbfs / mount.cifs then you can use smbclient with debug option to find out some more on the connectivity / authentication issue by using the smb share server IP address instead of hostnae and lets say a debug level of 3 like so:





smbclient -d3 -L // -A /root/.smbcredentials

[0] smbclient -d3 -L // -A /home/acteam/.smbcredentials     lp_load_ex: refreshing parameters
Initialising global parameters
rlimit_max: increasing rlimit_max (1024) to minimum Windows limit (16384)
Processing section "[global]"
WARNING: The "syslog" option is deprecated
added interface eth0 ip= bcast= netmask=
Client started (version 4.3.11-Ubuntu).
Connecting to at port 445
Doing spnego session setup (blob length=120)
got OID=
got OID=1.2.840.48018.1.2.2
got OID=1.2.840.113554.1.2.2
got OID=1.2.840.113554.
got OID=
got principal=not_defined_in_RFC4178@please_ignore
GENSEC backend 'gssapi_spnego' registered
GENSEC backend 'gssapi_krb5' registered
GENSEC backend 'gssapi_krb5_sasl' registered
GENSEC backend 'spnego' registered
GENSEC backend 'schannel' registered
GENSEC backend 'naclrpc_as_system' registered
GENSEC backend 'sasl-EXTERNAL' registered
GENSEC backend 'ntlmssp' registered
GENSEC backend 'ntlmssp_resume_ccache' registered
GENSEC backend 'http_basic' registered
GENSEC backend 'http_ntlm' registered
GENSEC backend 'krb5' registered
GENSEC backend 'fake_gssapi_krb5' registered
Got challenge flags:
Got NTLMSSP neg_flags=0x62898215
NTLMSSP: Set final flags:
Got NTLMSSP neg_flags=0x62088215
NTLMSSP Sign/Seal – Initialising with flags:
Got NTLMSSP neg_flags=0x62088215
NTLMSSP Sign/Seal – Initialising with flags:
Got NTLMSSP neg_flags=0x62088215
Domain=[TMGRID] OS=[Windows Server 2012 R2 Standard 9600] Server=[Windows Server 2012 R2 Standard 6.3]


        Sharename       Type      Comment
        ———       —-      ——-
        ADMIN$          Disk      Remote Admin
        C$              Disk      Default share
        Files           Disk
        IPC$            IPC       Remote IPC
        MappedDrive     Disk
Connecting to at port 139
Connecting to at port 139
Connection to failed (Error NT_STATUS_RESOURCE_NAME_NOT_FOUND)
NetBIOS over TCP disabled — no workgroup available


Sum it up

Lets Summarize a bit, here I described how to mount smbfs and cifs mount shares with mount command, how to define the auto mount on server boot via /etc/fstab, how to mount manually /etc/fstab defined mount and what should be the syntax of .smbcredentials user / pass file and also pointed how to debug problems on samba / windows server location share mounts with smbclient command.

Howto create Linux Music Audio CD from MP3 files / Create playable WAV format Audio CD Albums from MP3s

Tuesday, July 16th, 2019


Recently my Mother asked me to prepare a Music Audio CD for her from a popular musician accordionist Stefan Georgiev from Dobrudja who has a unique folklore Bulgarian music.

As some of older people who still remember the age of the CD and who had most likely been into the CD burning Copy / Piracy business so popular in the countries of the ex-USSR so popular in the years 1995-2000 audio ,  Old CD Player Devices were not able to play the MP3 file format due to missing codecs (as MP3 was a proprietary compression that can't be installed on every device without paying the patent to the MP3 compression rights holder.

The revolutionary MP3 compression used to be booming standard for transferring Music data due to its high compression which made an ordinary MP3 of 5 minutes of 5MB (10+ times more compression than an ordinary classic WAV Audio the CPU intensiveness of MP3 files that puts on the reading device, requiring the CD Player to have a more powerful CPU.

Hence  due to high licensing cost and requirement for more powerful CPU enabled Audio Player many procuders of Audio Players never introduced MP3 to their devices and MP3 Neve become a standard for the Audio CD that was the standard for music listening inside almost every car out there.

Nowdays it is very rare need to create a Audio CD as audio CDs seems to be almost dead (As I heard from a Richard Stallman lecture In USA nowadays there is only 1 shop in the country where you can still buy CD or DVD drives) and only in third world as Africa Audio CDs perhaps are still in circulation.

Nomatter that as we have an old Stereo CD player on my village and perhaps many others, still have some old retired CD reading devices being able to burn out a CD is a useful thing.

Thus to make mother happy and as a learning excercise, I decided to prepare the CD for her on my Linux notebook.
Here I'll shortly describe the takes I took to make it happen which hopefully will be useful for other people that need to Convert and burn Audio CD from MP3 Album.


1. First I downloaded the Album in Mp3 format from Torrent tracker

My homeland Bulgaria and specific birth place place the city of Dobrich has been famous its folklore:  Galina Durmushlijska and Stefan Georgiev are just 2 of the many names along with Оркестър Кристал (Orchestra Crystal) and the multitude of gifted singers. My mother has a santiment for Stefan Georgiev, as she listened to this gifted accordinist on her Uncle's marriage.

Thus In my case this was (Стефан Георгиев Хора и ръченици от Добруджа) the album full song list here If you're interested to listen the Album and Enjoy unique Folklore from Dobrudja (Dobrich) my home city, Stefan Georgiev's album Hora and Rachenica Dances is available here


I've downloaded them from Bulgarian famous torrent tracker in MP3 format.
Of course you need to have a CD / DVD readed and write device on the PC which nowdays is not present on most modern notebooks and PCs but as a last resort you can buy some cheap External Optical CD / DVD drive for 25 to 30$ from Amazon / Ebay etc.


2. You will need to install a couple of programs on Linux host (if you don't have it already)

To be able to convert from command line from MP3 to WAV you will need as minimum ffmpeg and normalize-audio packages as well as some kind of command line burning tool like cdrskin  wodim which is
the fork of old good known cdrecord, so in case if you you're wondering what happened with it just
use instead wodim.

Below is a good list of tools (assuming you have enough HDD space) to install:


root@jeremiah:/ # apt-get install –yes dvd+rw-tools cdw cdrdao audiotools growisofs cdlabelgen dvd+rw-tools k3b brasero wodim ffmpeg lame normalize-audio libavcodec58


Note that some of above packages I've installed just for other Write / Read operations for DVD drives and you might not need that but it is good to have it as some day in future you will perhaps need to write out a DVD or something.
Also the k3b here is specific to KDE and if you're a GNOME user you could use Native GNOME Desktop app such brasero or if you're in a more minimalistic Linux desktop due to hardware contrains use XFCE's native xfburn program.

If you're a console / terminal geek like me you will definitely enjoy to use cdw

root@jeremiah:/ # apt-cache show cdw|grep -i description -A 1
Description-en: Tool for burning CD's – console version
 Ncurses-based frontend for wodim and genisoimage. It can handle audio and

Description-md5: 77dacb1e6c00dada63762b78b9a605d5


3. Selecting preferred CD / DVD / BD program to use to write out the CD from Linux console

cdw uses wodim (which is a successor of good old known console cdrecord command most of use used on Linux in the past to burn out new Redhat / Debian / different Linux OS distro versions for upgrade purposes on Desktop and Server machines.

To check whether your CD / DVD drive is detected and ready to burn on your old PC issue:


root@jeremiah:/# wodim -checkdrive
Device was not specified. Trying to find an appropriate drive…
Detected CD-R drive: /dev/cdrw
Using /dev/cdrom of unknown capabilities
Device type    : Removable CD-ROM
Version        : 5
Response Format: 2
Capabilities   :
Vendor_info    : 'HL-DT-ST'
Identification : 'DVDRAM GT50N    '
Revision       : 'LT20'
Device seems to be: Generic mmc2 DVD-R/DVD-RW.
Using generic SCSI-3/mmc   CD-R/CD-RW driver (mmc_cdr).
Supported modes: TAO PACKET SAO SAO/R96P SAO/R96R RAW/R16 RAW/R96P RAW/R96R

You can also use xorriso (whose added value compared to other console burn cd tools is is not using external program for ISO9660 formatting neither it use an external or an external burn program for CD, DVD or BD (Blue Ray) drive but it has its own libraries incorporated from libs.

Below output is from my Thinkpad T420 notebook. If the old computer CD drive is there and still functional in most cases you should not get issues to detect it.

cdw ncurses text based CD burner tool's interface is super intuitive as you can see from below screenshot:


CDW has many advanced abilities such as “blanking” a disk or ripping an audio CD on a selected folder. To overcome the possible problem of CDW not automatically detecting the disk you have inserted you can go to the “Configuration” menu, press F5 to enter the Hardware options and then on the first entry press enter and choose your device (by pressing enter again). Save the setting with F9.

4. Convert MP3 / MP4 Files or whatever format to .WAV to be ready to burn to CD

Collect all the files you want to have collected from the CD album in .MP3 a certain directory and use a small one liner loop to convert files to WAV with ffmpeg:

cd /disk/Music/Mp3s/Singer-Album-directory-with-MP3/

for i in $( ls *.mp3); do ffmpeg -i $i $i.wav; done

If you don't have ffmpeg installed and have mpg123 you can also do the Mp3 to WAV conversion with mpg123 cmd like so:


for i in $( ls ); do mpg123 -w $i.wav $i.mp3; done

Another alternative for conversion is to use good old lame (used to create Mp3 audio files but abling to also) decode
mp3 to wav.


lame –decode somefile.mp3 somefile.wav

In the past there was a burn command tool that was able to easily convert MP3s to WAV but in up2date Linux modern releases it is no longer available most likely due to licensing issues, for those on older Debian Linux 7 / 8 / 9 / Ubuntu 8 to 12.XX / old Fedoras etc. if you have the command you can install burn and use it (and not bother with shell loops):

apt-get install burn


yum install burn

Once you have it to convert


$ burn -A -a *.mp3


5. Fix file naming to remove empty spaces such as " " and substitute to underscores as some Old CD Players are
unable to understand spaces in file naming with another short loop.


for f in *; do mv "$f" `echo $f | tr ' ' '_'`; done


6. Normalize audio produced .WAV files (set the music volume to a certain level)

In case if wondering why normalize audio is needed here is short extract from normalize-audio man page command description to shed some light.

"normalize-audio  is  used  to  adjust  the volume of WAV or MP3 audio files to a standard volume level.  This is useful for things like creating mp3 mixes, where different recording levels on different albums can cause the volume to  vary  greatly from song to song."

cd /disk/Music/Mp3s/Singer-Album-directory-with-MP3/

normalize-audio -m *.wav


7. Burn the produced normalized Audio WAV files to the the CD


wodim -v -fix -eject dev='/dev/sr0' -audio -pad *.wav

Alternatively you can conver all your MP3 files to .WAV with anything be it audacity
or another program or even use 
GNOME's CDBurn tool brasero (if gnome user) or KDE's CDBurn which in my opinion is
the best CD / DVD burning application for Linux K3B.

Burning Audio CD with K3b is up to few clicks and super easy and even k3b is going to handle the MP3 to WAV file Conversion itself. To burn audio with K3B just run it and click over 'New Audio CD Project'.


For those who want to learn a bit more on CD / DVD / Blue-Ray burning on GNU / Linux good readings are:
Linux CD Burning Mini Howto, is Linux's CD Writing Howto on ibiblio (though a bit obsolete) or Debian's official documentation on BurnCD.

8. What we learned here

Though the accent of this tutorial was how to Create Audio Music CD from MP3 on GNU / Linux, the same commands are available in most FreeBSD / NetBSD / OpenBSD ports tree so you can use the same method to build prepare Audio Music CD on *BSDs.

In this article, we went through few basic ways on how to prepare WAV files from MP3 normalize the new created WAV files on Linux, to prepare files for creation of Audio Music CD for the old mom or grandma's player or even just for fun to rewind some memories. For GUI users this is easily done with  k3b,  brasero or xfburn.

I've pointed you to cdw a super useful text ncurses tool that makes CD Burninng from plain text console (on servers) without a Xorg / WayLand  GUI installed super easy. It was shortly reviewed what has changed over the last few years and why and why cdrecord was substituted for wodim. A few examples were given on how to handle conversion through bash shell loops and you were pointed to some extra reading resources to learn a bit more on the topic.
There are plenty of custom scripts around for doing the same CD Burn / Covnersion tasks, so pointing me to any external / Shell / Perl scripts is mostly welcome.

Hope this learned you something new, Enjoy ! 🙂

What Every Body is Saying – one of Best books on Body Language ever written

Tuesday, August 14th, 2018


Those interested in People Reading or holding a Management position position job inside some Small or Mid sized corporation could benefit greatly of a Book called
What Every Body is Saying

What Every Body is Saing is written by an ex-FBI Agent (JOE NAVANNO), probablythere are no actually ex-FBI agents, but that's a topic for another post.

The book is quick to read, especially if you follow the pictures of Body postures shown with their little description below.
Many of the Body Languages so commonly adopted by multitudes of people, thanks to the American of the Culture world-wide are being practiced
in some degree in mostly all people you might know (mostly unconsciously) …

What Every Body is Saying could be of a great help to people who want to make through in life and for Start-up company CEOs, Human Resource Managers, or anyone who want to better learn to communicate and Influence People.

Even in a normal family relations, being able to properly identify the Body Language of your Wife or kids would seriously benefit you and if you keep attention (focus) would reveal there short term-plans.


Adopting some of the suggested body languages in the book would definitely help you improve how people perceive you and practising some so called "Confident postures" could even boost your Confidence levels dramatically both when you're alone or when you are in a group of people or A Company Team Meeting.

Reading the Person Body language is of a great help also to understand the approximate Emotional / Spiritual state the person in front of you is and even if applied proparly could help you make the person or group of people be positively influenced to change from a negative to positive mindset
or when working on a project, could help you dramatically to make the people work more efficiently and boost their motivation / mood about the things, they have to someday do anyways.

The reader has to know of course that most of the mentioned body language cues are generalizations and in order to find out the exact messages being sent on non-verbal communication level depends on a multiple factors and many of the Body languages talked might be in a modified form and even some could be totally different from any of the described of the book.

However the observation practice (at least mine) shows that at least 60-70% of the described Body Language postures are adopted and used by mostly anyone out there.
To check the validity of the things described in the books just sit somewhere in a park or in a bar / caffeteria and watch carefully how people interact, you will be surprised how many things are being communicated non-verbally and how often the lack of one of the two, or two have severe communication issues, just because they couldn't synchronize their body language or lack the ability to read the other interlocutor's processed and communicated intentions.

The book when red at least for me was a wide eyes opener and even though as a Christian, I've always been doubting that any-generalization model trying to frame up people is very untrue and trying to influence people with your Body Language is bad sinful (kinda of satanic) practice, realizing that even Christians does communicate and do use body language (because they're conditioned by the society they lived in), that means that improving your Body Language to be more convincing in mostly anti-christian society we live can do you good favour to be adequate in society, or at least you can be aware of the existence of the Body Language and its meaning.

By the way, many of the models and gestures as translated described as a behaviour body interpretations are perhaps highly used nowadays by Agents across all the major Secret Services agencies such as CIA, MI6, KGB, Mussad etc.


This kind of things are learned in most business universities nowadays, but the way the Body Reading / Influencing knowledge is communicated in Business universities is a disaster, because it is usually compiled by Professors who alone are not expert or haven't been advanced enough in body language.
Thus even like that if you read the book, I'm sure you will benefit and perhaps reread it at least a couple of times in the coming years …

A summary of the book goes like this:

1. It starts with a short story on how the author get acquainted to the knowledge of body language and his personal life events

The author Joe Navarro was an emigrant from Cuba to US as the age of 8, because the author inability to speak English at all, his best way to understand what the other was saying or communicating in the first few years in US was to observe closely what the person in front was communicating non-verbally and makes guesses, what that could be.
His family and grandmother also played a key role to help him learn the craft of Body Language reaading.

Growing up and graduating college in the age of Baby Boomers, Joe Navarro was hired in FBI where he spend the following years as an agent specializing in Counter Intelligence
and behavior assessment.

2. It continues as the knowledge on Body interprations is being served in a very stuffed manner



The 3 key things to remember out of the book goes like that:

    A. At least 60% of what you say is not coming out of your mouth.
    B. There’s one more option next to fight or flight responce our brain does automatically
    C. To become a master at reading body language, you have to develop situational awareness.

The book claims that people tend to be stuck into 3 main states (as a result of the evolutionary development of species (Creationists and Christian fundamentalists could argue seriously here 🙂 ) , whenever facing a difficult situation these are:

  • Freeze
  • Fight
  • Flight

To sum up if you're looking for new ways to improve your current relationships with people and build a new ones, the book would definitely help you tremendously.
I've found the book in a PDF format with few simple searches online so those who can't afford it could also download it from the internet (at least as of time of writting this article).
A lot of the exampled Body confidence / influence postures described in the book you will find on mostly any Kids Cartoon and Internet top shows and in mostly everybody from TED Talks show and mostly all Youtube educational videos and podcasterers.

That's all Folks, Enjoy reading!



Virtual Keyboard for Linux and other Freedom respecting operating Systems

Monday, July 30th, 2018

How to install and Use Linux Virtual Keyboard and other freedom respecting Operating Systems

  •  Looking for a quick way to use VIRTUAL KEYBOARD ON LINUX COMPUTER OPERATING SYSTEM, you can do it just this 1 task in 3 simple steps  ???
    – Logical question emerges, WHY ??? would you need a virtual keyboard on Free Software OS such as Linux?
    Well, just because sometimes it is much more secure to use a Virtual Keyboard, especially if you have doubt that your keyboard has been tapped or a Key Logger (Sniffer), intercepting the Keyboard IN / OUT jacks, is installed on the computer or you might have sit on a computer of ,a friend running Linux, and you want to make sure he did not install sniffer to intercept your ,SSH login passwords and ,later hack into your Servers, after stealing, the password


  • Assuming you're on : – Debian / Ubuntu Linux, or other of the numerous IT systems such as ,FreeBSD / OpeBSD etc. out there, you can run simply this commands:


  •  apt-get install –yes florence
    * A. To make it, easily invokable for laters, create a small bash, shell script in directory; – location /usr/bin/virtual-keyboard like, the one below:

    vim /usr/bin/virtual-keyboard

    * B.. INside the file Place following 1 liner code



    * C… To later invoke it any time:
    Press ALT + F2 (or use Run Command Dialog in GNOME / KDE / Windomaker / IceWM whatever or any other crazy graphic environment of your choice and run:



How to make for loop (cycles) in KSH useful for FreeBSD / UNIX system administrators

Friday, November 3rd, 2017


Sometimes we have to administrate this operating systems such as FreeBSD / AIX / HP UX or even Mac OS server where by default due to historical reasons or for security bash shell is not avialable. That's not a common scenario but it happens so if as sysadmin we need to create for loops on ksh it is useful to know how to do that, as for loop cycles are one of the most important command line tools the sysadmin swiss army knife kind of.

So how to create a for loop (cycle) in ksh (Korn Shell)?

The most basic example for a KSH loop shell is below:

for i in 1 2 3 4 5
  echo "Welcome $i times"


Add the content to any file lets say ksh_loop.ksh then make it executable as you do in bash shells



$ chmod +x ksh_loop.ksh
$ ksh ksh_loop.ksh


The overall syntax of the for loop ksh command is as follows:



for {Variable} in {lists}
    echo ${Variable}


Hence to list lets say 20 iterations in a loop in ksh you can use something like:

for i in {1..20}
  echo "Just a simple echo Command $i times";
# add whatever system commands you like here


Example for some useful example with KSH loop is to list a directory content so you can execute whatever command you need on each of the files or directories inside


for f in $(ls /tmp/*)
        print "Iterating whatever command you like on /tmp dir : $f"

Other useful for loop iteration would be to print a file content line by line just like it is done in bash shell, you can do that with a small loop like belows:


for iteration_variable in $(cat  file_with-your-loved-content-to-iterate.txt)
        print "Current iteration like is : $iteration_variable"


How to turn keyboard backlight on GNU / Linux, keyboard no backlight solution

Friday, October 20th, 2017


If you're a GNU / Linux user and you happen to buy a backlighted keyboard, some nice new laptop whose keyboard supports the more and more modern keyboard growing or if you happen to install a GNU / Linux for a Gamer friend no matter the Linux distribution, you might encounter sometimes  problem even in major Linux distributions Debian / Ubuntu / Mint / Fedora with keyboard backlight not working.

Lets say you buy a Devastator II backlighted keyboard or any other modern keyboard you plug it into the Linux machine and there is no nice blinking light coming out of the keyboard, all the joy is gone yes I know. The free software coolness would have been even more grandiose if your keyboard was shiny and glowing in color / colors 🙂

But wait, there is hope for your joy to be made complete.

To make the keyboard backlight switch on Just issue commands:


xmodmap -e 'add mod3 = Screen_Lock'


# Turn on the keyboard bright lamps
xset led on

# Turns off the keyboard bright lamps
xset led off

If you want to make the keyboard backlight be enabled permanent the easiest solution is to

– add the 3 command lines to /etc/rc.local

E.g. to do so open /etc/rc.local and before exit 0 command just add the lines:


vim /etc/rc.local


xmodmap -e 'add mod3 = Screen_Lock'

# Turn on the keyboard bright lamps
xset led on

# Turns off the keyboard bright lamps
xset led off

If you prefer to have the keyboard colorful backlight enable and disabled from X environment on lets say GNOME , here is how to make yourself an icon that enabled and disables the colors.

That's handy because at day time it is a kind of meaningless for the keyboard to glow.

Here is the shell script:

sleep 1
xset led 3
xmodmap -e 'add mod3 = Scroll_Lock'

I saved it as /home/hipo/scripts/

(don't forget to make it executable!, to do so run):


chmod +x /home/hipo/scripts/

Then create  the .desktop file at /etc/xdg/autostart/backlight.desktop so that it runs the new shell script, like so:

[Desktop Entry]
Name=Devastator Backlight