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Commands used in Dockefile - Part4

  Docker is an opensource tool used for virtualization and deliver software in the form of packages called Containers. It is one of the most important tools used in networking domain.  Dockerfile  is a template for building the image which contains commands needed to package the software. In this post, I am going to explain the commands ADD & COPY used in  Dockerfile .   ADD Command:   ADD command is used to copy files, directories or files from remote URLS to destination path in the image. The source paths can contain wildcards.   If the destination has relative path, it is relative to the Working directory of the image. Note that source path is always relative to the Docker build context.   ADD command will not support authentication. So, if there are any protected files to be added in  Dockerfile  building, use other tools like curl or  wget   Dockerfile  copying Single & Multiple files, directory using ADD inst...

Notes on HTTP Response Status codes

  In Networking domain or API testing, it is often common that we should be able to interpret the status codes in Http Response received when we send a request and take a decision . .  Also, in technical interviews related to networking domain, “ Explain Http Status codes”  is one of the common interview questions. In this post, I am giving overview of Http Status codes. Http response status codes can be broadly classified into below 5 categories:   1xx - Informational codes 2xx - Success codes 3xx - Redirection codes 4xx - Client Error or Bad Request 5xx - Server Error 1xx Codes: 1xx codes means that server has received the request and understood the need of the client. These status codes indicate client to wait for getting a final response. An example where we may get these codes is that the client asking server to switch protocols. 2xx Codes: 2xx codes means that server has received, understood and accepted. Some important codes and meaning are given below: ...

Notes on IPv4, IPv6 and MAC representations

  In companies related to networking domain, “ Explain IPv4, IPv6 and MAC ” is one of the common questions asked in technical interview. This post provides overview of these concepts. IP: IP is the protocol used in Networking layer. It is responsible for the delivering packets from source to destination based on the identifier known as IP address of the device. There are two popular ways of representing the devices in the network. They are: IPv4  (Internet  Protocol version 4) IPv6 (Internet Protocol version6) IPv4:   This version of IP uses 32-bit addresses to identify the device on the network.  Therefore,  the total number of addresses possible with IPv4 is 2 32 . These  32-bit  addresses are divided into 4 octets (batch of 8 bits) with each octet represented in decimal numbers and octets are separated by dot. In IPv4 the loopback address of a device is  127.0.0.1 . IPv4 supports unicasting, broadcasting and multicasting. To map IPv4 addre...

Virtual Interface Creation and deletion in Linux Operating System

Virtual interfaces are the interfaces that allows physical connection to have more than one interface. These help in tagging the LAN packet with ID’s that may be used to segregate the traffic or customer. This article focuses on the creation and removal of Virtual Interfaces using Open Source tool  Vlan   and command  ip  link  in Linux Operating system. All the commands are prefixed with  sudo  to run commands as a root user Vlan : Vlan  is an open source tool that helps in creating and removing the virtual interfaces over a physical interface. To use  Vlan , one needs to install  vlan  using  sudo  apt-get install  vlan   on Linux Operating System Adding Virtual Interface using  Vlan  tool: Assume you have a physical interface named enp0s4. To create a Virtual Lan or Sub interface, the command is  vconfig  add < Physical_Interface_Name > < tag_number > . ...