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Showing posts with label VPN. Show all posts
Showing posts with label VPN. Show all posts

Friday, May 31, 2013

Infrastructure: Testing, VPN and network issues relating to external teams

When dealing with testing or development by external teams, there are a lot of infrastructural issues to deal with, and in a number of cases, teams have not prepared some kind of process documentation to take care of such needs and processes. Some of the external teams that can be involved in the process of development or testing for a software application include the following:
- External teams that are working as an extension of the testing team. This is getting more and more common, whereby the testing team can be expanded as necessary by adding vendors to the testing resources. However, when the these external vendors need to start their work, they need access to the testing infrastructure such as test cases repository and the defect management software.
- External teams working on the localization (conversion of the software into different languages). Such teams typically work on both development and testing of the application in different languages and need access to the source repository, as well as the testing infrastructure (test plan and case repository, defect management software, and so on).
- Teams working on the documentation of the product typically need access to the defect management software, since there can be several issues that need to be documented which are typically present in the defect management software, and the documentation team would be provided access to the defect management software.

For these 3 teams and others working in a similar area, if they are located outside the organization, then there may be a necessity for them to be provide the required VPN access to get access to all these tools. In modern secure organizations, such access policies would go through an approval process, and to ensure that such a process is accelerated, it makes sense to prep the approving authorities about these requests for approval.

- External testers / pre-release testers. Such pre-release testers typically do not need any access to source code repository or the testing infrastructure. However, these testers do need a platform where the defects they have logged get into the defect management software in an easy and transparent way (and where the testers are not expected to do any additional work - in some cases, it is as simple as providing them a web page where they can enter the defects that they have found, and some additional parameters that testers  are expected to enter but pre-release testers are not expected to enter are entered by default).

For all these teams, there may be other access issues that teams may not have thought about. Typically when a team has any kind of feature that provides access to an online feature, such features are available in staged servers that need some kind of setting or special access. For ensuring that all the teams listed above and similar teams do not get stuck, it is required to plan for such an access. We had a problem in the past whereby an important online feature was rolled out to the press reviewing team, but there was a big screw up relating to the access for these features, and the team was not able to provide access for around 3 days, in which time, some of the press withdrew - a big disaster. So, a great team has plans for all these before they look to execute such features.


Wednesday, July 22, 2009

Quick Tech Tip: Layer 2 Tunneling protocol : L2TP

Layer Two Tunneling Protocol (L2TP) is an extension of the Point-to-Point Tunneling Protocol (PPTP) used by an Internet service provider (ISP) to enable the operation of a virtual private network (VPN) over the Internet.
The two end components that make up L2TP are the L2TP Access Concentrator (LAC) which is the device that physically terminates a call and the L2TP Network Server (LNS), which is the device that terminates and possibly authenticates the PPP stream. Once a tunnel is established, the network traffic between the peers is bidirectional. To be useful for networking, higher level protocols are then run through the L2TP tunnel. To facilitate this L2TP session (or call) is established within the tunnel for each higher-level protocol such as PPP. Either the LAC or LNS may initiate sessions. The traffic for each session is isolated by L2TP, so it is possible to set up multiple virtual networks across a single tunnel.
The packets exchanged within an L2TP tunnel are either categorized as control
packets or data packets. L2TP provides reliability features for the control packets, but no reliability for data packets. Reliability, if desired, must be provided by the nested protocols running within each session of the L2TP tunnel.
An L2TP tunnel can extend across an entire PPP session or only across one segment of a two-segment session. This can be represented by four different tunneling models :
- Voluntary Tunnel model : a tunnel is created by the user, typically by the use of an L2TP enabled client which is called the LAC client. The user will send L2TP packets to the Internet Service Provider (ISP) which will forward them on to the LNS.
- Compulsory tunnel model-incoming call: a tunnel is created between ISP LAC and the LNS home gateway.
- Compulsory tunnel model-remote dial the home gateway (LNS) initiates a tunnel to an ISP (LAC) (outgoing call) and instructs the ISP to place a local call to the PPP enabled client which is the remote user.
- L2TP Multi-hop connection : It is a way of redirecting L2TP traffic on behalf of client LACs and LNSs. A Multi-hop connection is established using an L2TP Multi-hop gateway. A tunnel is established from a client LAC to the L2TP Multi-hop gateway and then another tunnel is established between the L2TP Multi-hop gateway and a target LNS. L2TP traffic between client LAC and LNS is redirected to each other through the gateway.


Quick Tech Tip: Point-to-point tunneling protocol - PPTP

Overview of Point-to-point Protocol:

The Point-to-Point Protocol (PPP) provides a standard method for transporting multi-protocol datagrams over point-to-point links. PPP was originally emerged as an encapsulation protocol for transporting IP traffic between two peers.PPP is comprised of the following main components:
* Encapsulation: A method for encapsulating multi-protocol datagrams.
* Link Control Protocol: The LCP is used to automatically agree upon the encapsulation format options, handle varying limits on sizes of packets, detect a looped-back link and other common misconfiguration errors, and terminate the link.
* Network Control Protocol: An extensible Link Control Protocol (LCP) for establishing, configuring, and testing and managing the data-link connections.
* Configuration: Easy and self configuration mechanisms using Link Control Protocol. This mechanism is also used by other control protocols such as Network Control Protocols (NCPs).

Introduction TO PPTP :

PPTP packages data within PPP packets, then encapsulates the PPP packets within IP packets (datagrams) for transmission through an Internet-based VPN tunnel. PPTP supports data encryption and compression of these packets.
The PPTP protocol is designed to perform the following tasks:
* Query the status of Comm Servers
* Provide In-Band management
* Allocate channels and place outgoing calls
* Notify NT Server on incoming calls
* Transmit and Receive User Data with flow control in both directions
* Notify NT Server on disconnected calls.

PPTP-based Internet remote access VPNs are by far the most common form of PPTP VPN. In this environment, VPN tunnels are created via the following two-step process:
1. The PPTP client connects to their ISP using PPP dial-up networking.
2. Via the broker device (described earlier), PPTP creates a TCP control connection between the VPN client and VPN server to establish a tunnel.

Once the VPN tunnel is established, PPTP supports two types of information flow:
* control messages for managing and eventually tearing down the VPN connection. Control messages pass directly between VPN client and server.
* data packets that pass through the tunnel, to or from the VPN client.

PPTP also supports VPN connectivity via a LAN.
PPTP supports authentication, encryption, and packet filtering.

Though PPTP remains a popular choice for VPNs, one drawback of PPTP is its failure to choose a single standard for authentication and encryption. Two products that both fully comply with the PPTP specification may be totally incompatible with each other if they encrypt data differently.


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