How to Set the DSCP Flag in Windows and Linux

QoSmappingDSCPDSCP (Differentiated Services Code Point) is a series of bits in the IP header for classification purposes. These bits specify the precedence value of the packet, the drop probability, and the network service used.

Before setting the DSCP flag with a desired value, you need to take some things into consideration. You cannot force the DSCP flag from the Data Distribution Service (DDS) middleware, but you can suggest the system use a specific value. The reason is that all network elements such as switches and routers must have the capability and be enabled to actually use the TOS bits to treat higher-priority packets differently (TOS is an older mechanism to prioritize packets). In addition, many network transports are not capable of managing packet priority. All this makes it impossible for DDS to control the prioritization of data at the network level. Continue reading

Polycom Cannot download certificate because domain is not accessible

Polycom-cannot-download-certificateOn first sign in Polycom phone cannot download certificate because domain is not accessible and displays the following messages: Continue reading

MSSQL Error – Access to the remote server is denied because the current security context is not trusted

mssql-error-access-to-the-remote-server-is-denied-because-the-current-security-context-is-not-trustedWhen trying to load data from  database that is in AlwaysOn High Availability Group from Microsoft Excel the following error occurs:

Access to the remote server is denied because the current security context is not trusted Continue reading

SQL Error – The database owner SID recorded in the master database differs from the database owner SID

When trying to execute Stored Procedures on a particular Database we got the following error:

The server principal “domain\user” is not able to access the database “dbXYZ” under the current security context.

The database owner SID recorded in the master database differs from the database owner SID recorded in database ‘dbXYZ’. You should correct this situation by resetting the owner of database ‘dbXYZ’ using the ALTER AUTHORIZATION statement. Continue reading

odbc_log: Unable to retrieve database handle. CDR failed.

Asterisk PBXI correctly configured ODBC connection on Asterisk server to MSSQL database in Always On cluster.

The working configuration was as follows: Continue reading

How to correctly stop/reboot Skype for Business server

skype-for-businessSkype for Business like any other service needs periodic maintenance and that’s when you need to know how to gracefully stop Skype for Business service without losing a quorum.

Before stopping Skype for Business service make sure you will have more than 50% of front end servers running. Continue reading

How to find all files containing specific text in Linux

Finding files containing text string in Linux is the easy task with the grep utility. grep also allows you to find files with specific text by searching directories recursively by defining -r key. Here are a few examples:

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Asterisk crashes on load

asterisk-invalid-pointerWhile loading Asterisk crashes with “invalid pointererror like in the backtrace below:

Loading Continue reading

How to reset MySQL/MariaDB root password

mysql-logo-imageStart session ssh (using root if possible).

Edit my.cnf file using.

sudo vi /etc/my.cnf

Add line to [mysqld] block: Continue reading

Parse JSON in Asterisk: how to install res_json

Asterisk PBXIf you need to talk to external API and parse JSON in Asterisk dialplan you will need res_json installed. Unfortunately it’s not bundled in Asterisk installation yet but here is how you can install res_json in Asterisk: Continue reading

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