Why Hyper-V virtual machines are not always available over the network

Suppose the server has one network card and in network connections it can be seen as “Ethernet”, but after adding the Hyper-V role, a virtual switch vEthernet (…) is created.

Virtual machines can be seen from other computers but can not be seen from the local.

Therefore, for virtual machines to be accessible from the local machine, you must disable the DHCP client to Ethernet, or assign an IP address manually, then the virtual switch vEthernet (…) will receive IP instead of Ethernet because they have the same The MAC address.

How to delete a page VKontakte

To delete a VK page, you need to login using your login and password, click the upper right of the icon and select “Settings”.
Below, click on the link “You can delete your page”.

Next, you need to select the reason for the deletion, you can uncheck the “Tell your friends” box if you do not want all friends to see the message and the reason for the deletion.
And click “Delete page”.

In my case, a message was displayed that the page was deleted and it can be restored to the specified date (within 7 months).

Using netwox

I will give examples of using netwox and describe them.
I described the netwox installation in this article – Установка netwox

Example of a standard startup:

sudo netwox

netwox has quite a lot of functions, you can see them by pressing after starting the number 3 and Enter.

Network configuration display:

sudo netwox 1

Display debugging information:

sudo netwox 2

Display information about the IP address or host name:

sudo netwox 3 example.com

Displaying information about the MAC address:

sudo netwox 4 -e 00:15:5D:38:01:08

Obtaining MAC addresses from the IP list:

sudo netwox 5 -i

Display information that will be used to reach the specified IP address:

sudo netwox 6

Sniffer, displaying the transmitted packets on the screen:

sudo netwox 7

Sniffer, displaying only the list of open ports that were used in the captured packets:

sudo netwox 8

Sniffer, mapping of MAC and IP addresses:

sudo netwox 9

An example of capturing packets and displaying brief statistics (the number of packets counted, the size of packages, the percentage of the number of packets (c%), the percentage of the size (s%)):

netwox 10 -d eth0

Convert a digit to an encrypted one:

sudo netwox 21 -n number

Converting a string to an encrypted string (sha256, md5, etc.):

sudo netwox 22 -d text

Show ASCII table:

sudo netwox 23

Check the security of the directory:

sudo netwox 25 /tmp/

Example of ICMP PING:

sudo netwox 49 -i

Example of ARP PING:

sudo netwox 55 -i

Example ICMP route tracing:

sudo netwox 57 -i examle.com

Example of TCP route tracing:

sudo netwox 59 -i examle.com

Example UDP route tracing:

sudo netwox 61 -i examle.com

Example of port scanning:

sudo netwox 67 -i -p 1-1000

ICMP scanning for availability:

sudo netwox 65 -i

TCP port access scan:

sudo netwox 67 -i -p 80

UDP port access scan:

sudo netwox 69 -i -p 80

ARP scanning:

sudo netwox 71 -i

Flood random fragments:

sudo netwox 74 -i

Filling the table of MAC-addresses of the switch by sending a flood:

sudo netwox 75


sudo netwox 76 -i -p 80


Installing and Configuring OpenFire

OpenFire – A cross-platform XMPP server written in Java.

For the test, I will install OpenFire in Ubuntu Server 16.04 and describe the process.

Since OpenFire requires Java, let’s see the installed version on the system:

java -version

If necessary, install Java:

sudo apt-get install default-jre

Then go to the download page http://www.igniterealtime.org/downloads/index.jsp#openfire, click download and copy the link.

Download, adding at the end the copied link instead of LINK:

wget -O openfire.deb LINK

For example:

wget -O openfire.deb http://www.igniterealtime.org/downloadServlet?filename=openfire/openfire_4.2.1_all.deb


sudo dpkg --install openfire.deb

Now it remains to open in the browser http://YourServer:9090/ and follow the prompts.

After that, the installation of OpenFire will be completed.

If necessary, you can stop, start, or restart OpenFire like this:

/etc/init.d/openfire {start|stop|restart|force-reload}

Installing and Configuring SSMTP

SSMTP – an alternative to sendmail for sending mail, allows you to configure sending via third-party mail servers.

To install in Ubuntu, use the command:

sudo apt-get install ssmtp mailutils

Next, open the /etc/ssmtp/ssmtp.conf file in any text editor (in the nano, press Ctrl+X to exit, y/n to save or discard changes):

sudo nano /etc/ssmtp/ssmtp.conf

Comment out all and set up as shown below for an example:


If you use Google mail, you will probably need to allow “Untrusted applications” in the settings at https://myaccount.google.com/security.

Also open the /etc/ssmtp/revaliases file in the text editor:

sudo nano /etc/ssmtp/revaliases

And add:


Let’s try to send the letter to the specified address (after the command we will type the desired text and put a point for completion):

sendmail -v admin@example.com

Letters must be sent from the address specified in the file /etc/ssmtp/ssmtp.conf.

How to delete a Foursquare account

For the test, I delete the Foursquare account.

First go to the account using your login and password, then click on the user’s icon in the upper right, select “My profile” – “Privacy settings”, in the text we find the link “delete your account” and click on it.

Direct link to delete – https://foursquare.com/delete_me

In the opened page, you must specify the reason for the deletion and click “Delete Account”, then enter the password for confirmation.

That’s all.

Using Linux ISG

View all sessions:

/opt/ISG/bin/ISG.pl | less

View information about a specific session:

/opt/ISG/bin/ISG.pl | grep

Viewing the number of sessions:

/opt/ISG/bin/ISG.pl show_count

Deleting a specific session:

/opt/ISG/bin/ISG.pl clear
/opt/ISG/bin/ISG.pl clear <IP-address | Virtual# | Session-ID>

Change the speed for a specific session (incoming/outgoing, for example 100 MB/s):

/opt/ISG/bin/ISG.pl change_rate 102400 102400

I note that the speed is specified in kilobytes, and when viewed in the table of sessions is displayed in bytes.

I’ll describe the possible keys to the flags:
A (Session approved)
X (Session not approved)
S (This is a service (or sub-session))
O (Service administrative status is enabled)
U (Online service (RADIUS account is active, traffic flow))
T (Type of service – “tagger”)
Z (Disconnected)

Restoring MySQL tables

I’ll give an example of a simple check of tables of all databases using mysqlcheck:

mysqlcheck -u root -p -A

Where the -u option specifies the user name under which to connect to MySQL, -p to request a password, -A to check the tables of all databases.

Example of restoring a specific database:

mysqlcheck -u root -p -r db_name

Example of restoring a specific table in the specified database:

mysqlcheck -u root -p -r db_name table_name

I’ll describe the possible startup options.

Checking all databases and their tables, except INFORMATION_SCHEMA and performace_schema:

--all-databases, -A

You can specify the list of databases using the option:

--databases, -B

Run all with one query instead of the individual for each database:

--all-in-1, -1

Analyze tables:

--analyze, -a

After checking, repair the damaged tables:


Specify the address of the connection to the MySQL server (for example, if there are several):


Connecting to the MySQL server on the specified node:

--host=host_name, -h host_name

Directory with character settings:


Checking the tables for errors (default):

--check, -c

Check the tables that have changed since the last check or that were not closed properly:

--check-only-changed, -C

Checking the tables for compatibility with the current version of the server:

--check-upgrade, -g

Data compression is transmitted between the client and the server if both support it:


Write and display debugging information (on the standard mysqlcheck test in Ubuntu 16.04 was compiled without debug support):


Specifying the default character set:


Use only the specified parameter file:


The following option makes the test longer and guarantees the integrity of the tables, it will also take a lot of time to recover and produce many unnecessary rows:

--extended, -e

Check only the tables that were not closed properly:

--fast, -F

Continue even in the case of SQL errors:

--force, -f

Faster than extended, there are 99.99% errors:

--medium-check, -m

Do not read the options files, however the .mylogin.cnf file will be read:


See also my article – Connecting to MySQL from localhost without entering a password.

Optimize tables:

--optimize, -o

Specify the password when connecting:

--password[=password], -p[password]

TCP/IP port number for connection:

--port=port_num, -P port_num

Displaying the name of the program and all the parameters it receives from the parameter files:


Specify the connection protocol:


A quick method for checking tables, prevents scanning of lines for checking invalid links:

--quick, -q

Performing repairs:

--repair, -r

Quiet mode, only errors are displayed:

--silent, -s

Skip specified database:


Specifying the socket when connecting:

--socket=path, -S path

Connection using SSL:


Override -databases or -B, all the name arguments following the option are treated as table names:


Specifying a list of protocols separated by commas, which are allowed to be used for encrypted connections:


When recovering, get the table structure from the .frm file:


The MySQL user name that will be used when connecting:

--user=user_name, -u user_name

Detailed mode, more information is displayed:

--verbose, -v

Display version of mysqlcheck and exit:

--version, -V

See also:
Installing and configuring a MySQL server on Ubuntu

View information about MySQL databases

To view information about MySQL databases and their tables, we first connect to the MySQL console, for example, as root:

mysql -u root

Or so, if you need to enter a password:

mysql -u root -p

Let’s see a list of existing databases:


You can select a database like this:

USE dbname;

See which database is currently selected:


To see which tables the selected database contains:


To view the structure of a particular table, execute the command:

DESCRIBE tablename;

Where Field is the name of the column, Type is the data type, Null – determines whether the column can contain NULL values, Key – whether the column is indexed, Default – determines the default value for the column.

To see information about the indexes of the table, you can do this:

SHOW INDEX FROM tablename;

View information about the table, the encoding, its type (ENGINES), etc. you can use:


To see what types the server supports, you can do this: