UnderStanding Systems Management Server (SMS)

Friday, April 16, 2010

Systems Management Server (SMS) Overview

SMS 2.0 is a Microsoft BackOffice systems management tool that can both operate in and manage an assortment of network environments. Systems Management Server (SMS) enables network environments and network resources to be centrally controlled. The core control point or center of Systems Management Server is the SMS Administrator console. This is a snap-in to the Microsoft Management Console (MMC). The industry standard for Web-Based Enterprise Management (WBEM) is the core of SMS data collection and presentation.

The main functions of SMS are listed here:

• Resource discovery

• Hardware and software inventory

• Software distribution

• Software metering

• Network Analysis

• Remote support through the Remote Tools feature

The SMS Administrator console is used to access and initiate these SMS 2.0 functions. A process known as resource discovery must be performed first to find computers, network hardware, and groups and users.

The main SMS components are listed here:

• SMS site: A SMS site specifies the computers, other networking hardware, users and groups, and all resources which will be managed through SMS. The SMS environment is made up of one or multiple SMS sites. You define a SMS site based on IP subnet address.

An SMS site consists of the following SMS components

• SMS site server

• SMS site systems

• SMS clients and resources

The structure that links multiple sites together is called a hierarchy. The hierarchy is created by linking sites together so that parent-child relationships can be formed:

• Parent site: This is a SMS site that contains one or multiple additional site beneath it.

• Child site: This is a SMS site that has a parent site residing over it in the hierarchy.

There are also two different types of sites that assist in organizing the administration of the SMS environment:

• Primary site

• Secondary site

SMS site server: This is the Windows server on which SMS 2.0 is installed and running. The SMS site server is the main access point between the SMS database and administrators. The SMS server manages the SMS site and component attributes. The SMS site server must be installed on a domain controller or on a member server. It cannot be installed on a stand-alone server.

SMS site system: This is a Windows server that carries out one of multiple SMS roles for the SMS site. When installing SMS, the default configuration is that all SMS roles are installed on an SMS site server.

The SMS roles are:

• Logon points: This is a SMS site system that is the initial connection point between a SMS site and client computer. Functions performed by logon point includes:

  • Collection of discovery information on the client.

  • Determines the site assignment of the client.

  • Pass the client a list of client access points (CAPs).

• Client access points (CAPs): This is a SMS site system that operates as the exchange point between SMS clients and the SMS site server. At the CAP; inventory, and status information and discovery information is gathered. Advertisement information can be retrieved from the CAP.

• Distribution points: This is a SMS site system that installs the following components which deal with running a package at a SMS client computer:

  • Package files

  • Programs

  • Scripts

• Software metering servers: This is a SMS site system which enables administrators to perform a number of management activities:

  • Grant/deny licenses for applications running on an SMS client.

  • Monitor and track application usage on SMS clients.

  • Restrict application usage on SMS clients.

• SMS client: This is a computer running a Microsoft operating system listed below. A SMS client is installed through the SMS client component software, an is assigned to a SMS site.

  • Microsoft Windows Server 2003

  • Windows XP Professional

  • Microsoft Windows 2000

  • Microsoft Windows NT 4.0

  • Microsoft Windows NT 3.51, Service Pack 5 or above.

  • Microsoft Windows 98

  • Microsoft Windows 95

How To Flush DNS

Most DNS clients cache the results of name resolution requests. This means that the DNS clients will temporarily store the website names that you have been visiting lately. This process speeds up name resolution if multiple lookups are done to the same address, such as is common when browsing the web. Hence, if you visit Yahoo.com second time, the DNS client will already have the name mapped and hence will retrieve the mapping quickly.

Sometimes a bad DNS entry will be cached and you will need to either flush the DNS cache to get rid of it, or wait up to 24 hours for it to be dropped from the cache automatically. Given below is a comprehensive step-by-step process to flush the DNS.

How to Flush DNS in Microsoft Windows

In Microsoft Windows, you can use the command ipconfig /flushdns to flush the DNS resolver cache. Open the command prompt and type the following:

C:\>ipconfig /flushdns
Windows IP Configuration
Successfully flushed the DNS Resolver Cache.

The above command will completely flush the DNS, deleting any incorrect entries too. You can also use the command ipconfig /displaydns to view the DNS resolver cache.

Turning Off DNS Caching under Microsoft Windows

If you experience frequent issues with DNS caching under Microsoft Windows, you can disable client-side DNS caching with either of these two commands:

net stop dnscache
sc servername stop dnscache

This will disable DNS caching until the next reboot. To make the change permanent, use the Service Controller tool or the Services tool to set the DNS Client service startup type to Disabled. You can permanently disable DNS Client by following the below steps:

• Goto Start and click on Run.
• Type Services.msc in the Run command box.
• A window listing all the services will popup. Search for a service called DNS Client.
• Double click on the listed DNS Client service and click Stop. Similarly, you can restart it by clicking Start.

Tuning DNS Caching under Microsoft Windows

You can modify the behavior of the Microsoft Windows DNS caching algorithm by setting two registry entries in the HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Dnscache\Parameters registry key.

The MaxCacheTtl represents the maximum time that the results of a DNS lookup will be cached. The default value is 86,400 seconds. If you set this value to 1, DNS entries will only be cashed for a single second.

MaxNegativeCacheTtl represents the maximim time that the results of a failed DNS lookup will be cached. The default value is 900 seconds. If you set this value to 0, failed DNS lookups will not be cached.

Flush DNS in Mac OSX

In Mac OSX Leopard, you can use the command dscacheutil -flushcache to flush the DNS resolver cache:

bash-2.05a$ dscacheutil -flushcache

In Mac OSX versions 10.5.1 and before, the command lookupd -flushcache performed the same task:

bash-2.05a$ lookupd -flushcache

Flush DNS in Linux

In Linux, the nscd daemon manages the DNS cache. To flush the DNS cache, restart the nscd daemon. To restart the nscd daemon, use the command `/etc/init.d/nscd restart`.

What is VPN (Virtual Private Networking)?

Wednesday, March 17, 2010

VPN gives extremely secure connections between private networks linked through the Internet. It allows remote computers to act as though they were on the same secure, local network.

Advantages

* Allows you to be at home and access your company's computers in the same way as if you were sitting at work.
* Almost impossible for someone to tap or interfer with data in the VPN tunnel.
* If you have VPN client software on a laptop, you can connect to your company from anywhere in the world.

Disadvantages

* Setup is more complicated than less secure methods. VPN works across different manufacturers' equipment, but connecting to a non-NETGEAR product will add to difficulty, since there may not documentation specific to your situation.
* The company whose network you connect to may require you to follow the company's own policies on your home computers ( ! )

VPN goes between a computer and a network (client-to-server), or a LAN and a network using two routers (server-to-server). Each end of the connection is an VPN "endpoint", the connection between them is a "VPN tunnel". When one end is a client, it means that computer is running VPN client software such as NETGEAR's ProSafe VPN Client. The two types of VPN:

VPN Client-to-Server (Client-to-Box):

VPN Server-to-Server (Box-to-Box):

All NETGEAR routers support "VPN Passthrough", but "passthrough" simply means the router does not stop VPN traffic — you still need two endpoints.

The whole purpose of VPN is to prevent data being altered, so, for example, a passthrough router that is also running NAT will break the VPN connection.

NETGEAR Support will configure one VPN tunnel between two pieces of NETGEAR equipment to demonstrate that the equipment and VPN work. For other information:

* See the list of NETGEAR VPN documentation in VPN Configuration and Troubleshooting Resources.
* Read the product's Reference Manuals, available with the product's downloads.
* Make use of NETGEAR's cost-effective ProSupport. This support for advanced features is available by phone, or with an on-site NETGEAR representative.