SwitchNetConfig - Laptop users, quickly switch network and proxy configuration in different places

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• Download source - 23.2 Kb

Introduction

This is a tiny utility which stores multiple network and proxy configuration as profiles. You can apply a profile to set specific network setting and proxy from simple shortcuts.

Background

If you have a laptop, when you go to different places, you have to change Network configuration and browser proxy. I have to go to 4 different places everyday with my laptop; my university, my offices and my home. Everywhere I have to change my IP setting and IE Proxy. I could write a WMI Script to do all of them. Unfortunately, for some reason WMI is not working from VB Script in my laptop but somehow it is working from .NET. So, I have made a handy utility which I can use to store configuration profiles for different places and apply them very quickly just by pressing one key and a ENTER at system startup. This program automatically sets IP, Subnet, Gateway and DNS for my LAN card and also changes the IE Proxy setting.

Using the code

You can setup in 3 easy steps.

• 1. Click New and enter a profile name.
• 2. Set IP configuration
• 3. Set IE Proxy configuration

It’s even easier to use:

• 1. Press the first letter of your profile. For example, “h” for Home.
• 2. Press ENTER and wait as it applies the profile.
• 3. Press ESC to quit.

Points of Interest

It’s a very simple Winforms application written in C#. The key technologies are:

• 1. WMI
• 2. IE Registry tweaking
• 3. XML Serialization

WMI

Windows Management Intrumentation (WMI) helps you work with Network configuration. For example, the following code retrieves Network Setting for a given Network Card.

/// <summary>

/// Returns the network card configuration of the specified NIC

/// </summary>

/// <PARAM name="nicName">Name of the NIC</PARAM>

/// <PARAM name="ipAdresses">Array of IP</PARAM>

/// <PARAM name="subnets">Array of subnet masks</PARAM>

/// <PARAM name="gateways">Array of gateways</PARAM>

/// <PARAM name="dnses">Array of DNS IP</PARAM>

public static void GetIP( string nicName, out string [] ipAdresses, 
  out string [] subnets, out string [] gateways, out string [] dnses )
{
  ipAdresses = null;
  subnets = null;
  gateways = null;
  dnses = null;

  ManagementClass mc = new ManagementClass(
    "Win32_NetworkAdapterConfiguration");
  ManagementObjectCollection moc = mc.GetInstances();

  foreach(ManagementObject mo in moc)
  {
    // Make sure this is a IP enabled device. 

    // Not something like memory card or VM Ware

    if( mo["ipEnabled"] as bool )
    {
      if( mo["Caption"].Equals( nicName ) )
      {
        ipAdresses = (string[]) mo["IPAddress"];
        subnets = (string[]) mo["IPSubnet"];
        gateways = (string[]) mo["DefaultIPGateway"];
        dnses = (string[]) mo["DNSServerSearchOrder"];

        break;
      }
    }
  }
}

“Win32_NetworkAdapterConfiguration” gives you the collection of network adapters installed. Be careful, all the entries in this list may not be your LAN card.

Similarly you can set Network configuration just by a couple of lines.

/// <summary>

/// Set IP for the specified network card name

/// </summary>

/// <PARAM name="nicName">Caption of the network card</PARAM>

/// <PARAM name="IpAddresses">Comma delimited string 

///           containing one or more IP</PARAM>

/// <PARAM name="SubnetMask">Subnet mask</PARAM>

/// <PARAM name="Gateway">Gateway IP</PARAM>

/// <PARAM name="DnsSearchOrder">Comma delimited DNS IP</PARAM>

public static void SetIP( string nicName, string IpAddresses, 
  string SubnetMask, string Gateway, string DnsSearchOrder)
{
  ManagementClass mc = new ManagementClass(
    "Win32_NetworkAdapterConfiguration");
  ManagementObjectCollection moc = mc.GetInstances();

  foreach(ManagementObject mo in moc)
  {
    // Make sure this is a IP enabled device. 

    // Not something like memory card or VM Ware

    if( mo["IPEnabled"] as bool )
    {
      if( mo["Caption"].Equals( nicName ) )
      {

        ManagementBaseObject newIP = 
          mo.GetMethodParameters( "EnableStatic" );
        ManagementBaseObject newGate = 
          mo.GetMethodParameters( "SetGateways" );
        ManagementBaseObject newDNS = 
          mo.GetMethodParameters( "SetDNSServerSearchOrder" );
            
        newGate[ "DefaultIPGateway" ] = new string[] { Gateway };
        newGate[ "GatewayCostMetric" ] = new int[] { 1 };

        newIP[ "IPAddress" ] = IpAddresses.Split( ',' );
        newIP[ "SubnetMask" ] = new string[] { SubnetMask };

        newDNS[ "DNSServerSearchOrder" ] = DnsSearchOrder.Split(',');

        ManagementBaseObject setIP = mo.InvokeMethod( 
          "EnableStatic", newIP, null);
        ManagementBaseObject setGateways = mo.InvokeMethod( 
          "SetGateways", newGate, null);
        ManagementBaseObject setDNS = mo.InvokeMethod( 
          "SetDNSServerSearchOrder", newDNS, null);

        break;
      }
    }
  }
}

Internet Explorer Proxy

Changing Internet Explorer Proxy setting is a tricky job. There are 3 registry keys that you need to handle:

CURRENT_USER\ Software\Microsoft\Windows\CurrentVersion\Internet Settings

• ProxyServer – string – Name of proxy server
• ProxyEnable – integer – 1 for enabled, 0 for disabled
• ProxyOverride – string – a list of hosts that you need to directly access without proxy

XML Serialization

XML Serialization makes it very easy to persist object graph in human readable form. For example, this is the XML that the program generates:

<?xml version="1.0"?>
<ConfigWrapper xmlns:xsd="http://www.w3.org/2001/XMLSchema" 
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <Profiles>
    <anyType xsi:type="Profile">
      <Name>Home</Name>
      <NICProfiles>
        <anyType xsi:type="NICProfile">
          <Name>[00000001] Intel(R) PRO/100 
             VE Network Connection</Name>
          <IP>192.168.2.43</IP>
          <Subnet>255.255.255.0</Subnet>
          <Gateway>192.168.2.1</Gateway>
          <DNS>202.141.190.2,202.141.190.3</DNS>
        </anyType>
      </NICProfiles>
      <IEProfile>
        <UseProxy>true</UseProxy>
        <ProxyName>192.168.2.1:3128</ProxyName>
        <BypassLocal>true</BypassLocal>
        <BypassAddresses />
      </IEProfile>
    </anyType>

It makes it very easy to modify the file manually. You can save an entire object graph just by writing 3 lines of code:

// Use XML Serializer to serialize the content of the specified array list

XmlSerializer serializer = new XmlSerializer( typeof( ConfigWrapper ) );
// open the profile file

StreamWriter writer = new StreamWriter( PROFILE_FILE_NAME, false );        
// Serialize the array list to the file

serializer.Serialize( writer.BaseStream, wrapper );

History

• Ver 1.0 - Store multiple profiles, multiple NIC setting, IE Proxy
• (Planning) Ver 2.0 - Execute batch file before and after profile setting