VPN (virtual private network)

A virtual private network (VPN) is a technology that creates a safe and encrypted connection over a less secure network, such as the internet.

VPN technology was developed as a way to allow remote users and branch offices to securely access corporate applications and other resources. To ensure safety, data travels through secure tunnels, and VPN users must use authentication methods — including passwords, tokens or other unique identification procedures — to gain access to the VPN server.

VPNs are used by remote workers who need access to corporate resources, consumers who may want to download files and business travelers who may want to log into sites that are geographically restricted. VPN services are critical conduits through which data can be transported safely and securely.

How a VPN works and why you should use one

The two most common types of VPNs are remote access VPNs and site-to-site VPNs.

A remote access VPN uses a public telecommunication infrastructure like the internet to provide remote users with secure access to their organization’s network. This is especially important when employees are using a public Wi-Fi hotspot or other avenues to access the internet and connect to their corporate network.

A VPN client on a remote user’s computer or mobile device connects to a VPN gateway on the organization’s network. The gateway typically requires the device to authenticate its identity. Then, it creates a network link back to the device that allows it to reach internal network resources — e.g., file servers, printers and intranets — as though the gateway is on the network locally.

A remote-access VPN usually relies on either IP Security (IPsec) or Secure Sockets Layer (SSL) to secure the connection, although SSL VPNs are often focused on supplying secure access to a single application rather than to the entire internal network.

Some VPNs provide Layer 2 access to the target network; these require a tunneling protocol like the Point-to-Point Tunneling Protocol or the Layer 2 Tunneling Protocol running across the base IPsec connection.

VPN design, What is VPN

In addition to IPsec and SSL, other protocols used to secure VPN connectivity and encrypt data are Transport Layer Security and OpenVPN.

A site-to-site VPN uses a gateway device to connect an entire network in one location to a network in another — usually a small branch connecting to a data center. End-node devices in the remote location do not need VPN clients because the gateway handles the connection.

Most site-to-site VPNs connecting over the internet use IPsec. It is also common for them to use carrier MPLS clouds rather than the public internet as the transport for site-to-site VPNs. Here, too, it is possible to have either Layer 3 connectivity (MPLS IP VPN) or Layer 2 (virtual private LAN service) running across the base transport.

VPN services can also be defined as connections between specific computers, typically servers in separate data centers, when security requirements for their exchanges exceed what the enterprise network can deliver. Increasingly, enterprises also use VPN connections in either remote access mode or site-to-site mode to connect — or connect to — resources in a public infrastructure-as-a-service environment.

Newer hybrid-access scenarios put the VPN gateway itself in the cloud, with a secure link from the cloud service provider into the internal network.

Benefits of using a VPN

The justification for using VPN access instead of a private network usually boils down to cost and feasibility: It is either not feasible to have a private network — e.g., for a traveling sales rep — or it is too costly to do so.

In addition to providing a secure way for remote users to transmit or access information, VPN services are used for other purposes, as well. VPNs can hide a user’s browsing activity, which is particularly helpful with public Wi-Fi connections. VPNs also allow users to connect to sites that may be blocked geographically.

VPN performance may be affected by a variety of factors, among them, the speed of users’ internet connections, the types of protocols an internet service provider uses and the types of encryption the VPN uses. VPN services performance can also be affected by poor quality of service and conditions that are outside IT’s control.

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What is a proxy server?

Proxy server is a computer that sits between a client computer and the Internet, and provide indirect network services to a client. It may reside on the user’s local computer, or at various points between the user’s computer and destination servers on the Internet. A proxy server intercepts all client requests, and provide responses from its cache or forwards the request to the real server. A client computer is connected to the proxy server, which acknowledges client requests by providing the requested resource/data from either a specified server or the local cache memory. Client requests include files or any other resources available on various servers.

Types of Proxy servers
Proxy servers are classified into several types based on purpose and functionality. Some of the most common types and their uses can be described as below:

Web Proxy is the most common type of proxy application, which responds to the user requests by accessing resources from cached web pages and files available on remote web servers. This facilitates quick and reliable access to data for local network clients. If the requested resource is not found in the cache, then a web proxy fetches the file from the remote server, and saves a copy in the cache before returning it to the client.

Transparent Proxy is mostly used for caching websites and overcoming simple IP bans. However, such proxies do not provide any user anonymity since user’s original IP address is exposed. Transparent proxies are not specifically configured on the client computers.

Anonymous proxies do not hide the original IP address of the user; however, they provide adequate anonymity to most users. Anonymous proxies are easily detectable.

A distorting proxy, identifies itself as a proxy server, and modify the HTTP headers to disguise the original IP address.

Tunneling proxies are capable of passing client requests and return responses without making any modifications. These are also referred to as gateway proxies.

A forward proxy responds to client requests by retrieving data from a wide range of sources on the internet. It is also referred to as an Internet-facing proxy.

Open proxies belong to the category of forwarding proxy servers, which are accessible by any internet user since they can receive and return requests from any client computer. Meanwhile, anonymous open proxies are used for user anonymity to conceal the IP address.

Reverse proxies, also known as surrogates, usually receive requests from the Internet and forward them to internal network servers. A reverse proxy server forwards requests to one or more proxy servers, whose response is returned to the client computer, the user of which has no knowledge on the origin of the response.

What does CRM software do?

CRM software records customer contact information such as email, telephone, website social media profile, and more. It can also automatically pull in other information, such as recent news about the company’s activity, and it can store details such as a client’s personal preferences on communications.

The CRM system organizes this information to give you a complete record of individuals and companies, so you can better understand your relationship over time.

CRM software improves customer relationship management by creating a 360° view of the customer, capturing their interactions with the business, and by surfacing the information needed to have better conversations with customers.

What is CRM?

CRM or Customer Relationship Management is a strategy for managing an organisation’s relationships and interactions with customers and potential customers. A CRM system helps companies stay connected to customers, streamline processes, and improve profitability.

When people talk about CRM, they are usually referring to a CRM system, a tool that is used for contact management, sales management, productivity, and more. The goal of a CRM system is simple: Improve business relationships.

How to process Instant Payment Notification (IPN) messages

IPN is a message service that sends you a notification when any type of transaction occurs in your account. The messages are received and processed by your server(s).

Process overview

To receive and process Instant Payment Notification (IPN) messages:

  1. Create an IPN listener to receive and process the IPN messages sent by PayPal. For complete details on creating an IPN listener, see Implementing an IPN Listener.
  2. In your PayPal merchant account settings, enable the IPN Message Service and specify the URL of your listener.
  3. Continuously run the IPN listener on the website specified by your listener URL.

SVN-repository — with rapidSVN (GUI)

rapidSVN is a cross platform subversion client. It’s project page is http://rapidsvn.tigris.org/
On Ubuntu you can install it from the package manager.

checkout with rapidSVN

  • Open rapidSVN
  • rightclick on bookmarks and choose “add existing repository”
  • use “https://svn.typo3.org/Teams/DocTeam/” as location
  • you can now browse the online repository
  • to check out parts of the repository right click on the folder you want to check out and choose “checkout new working copy”
  • select a folder (destination directory) to store your local copy and press OK

You could also checkout without creating any bookmarks first:

  • Choose repository from the top menu
  • Click checkout
  • Enter relevant information and press OK

 

tag the new version

  • navigate in the left bookmarks-folder to the manual you want to tag. e.g. “typo3_tut”
  • click at folder “tags” – and it gets orange
  • click at top menu “modify” and menu-item “create new folder”
  • naming style “Version-1-0-0”
  • navigate to the folder “trunk” and select all inside
  • right click and choose “copy”
  • type in YOUR LOCAL location: /path/to/your/local/copy/DocTeam/manual/tags/Version-1-0-0 (NO trailing slash!)
  • check with the browser: http://forge.typo3.org/repositories/show/team-docteam

 

Commit/upload the changes

  • if you made changes to your local files they are displayed orange in the rapidSVN browser
  • to commit your changes just right click on the file name and choose “commit”

 

remember: our server is

https://svn.typo3.org/Teams/DocTeam/

How to use Terminal to delete all .svn folders recursively?

cd to/dir/where/you/want/to/start
find . -type d -name '.svn' -print -exec rm -rf {} \;
  • Use find, which does recursion
  • in the current directory .
  • filetype is directory
  • filename is .svn
  • print what matched up to this point (the .svn dirs)
  • exec the command rm -rf (thing found from find). the {} is a placeholder for the entity found
  • the ; tells find that the command for exec is done. Since the shell also has an idea of what ; is, you need to escape it with \ so that the shell doesn’t do anything special with it, and just passes to find