Here you will find solutions of many problems on spoj. If you want solution of some problem which is not listed in blog or have doubt regarding any spoj problem (which i have solved) or any programming concept (data structure) you can mail me @
And my humble request to you all that don't copy the code only try to understand the logic and algorithm behind the code. I have started this because if you tried as hard as you can and still can't find any solution to the problem then you can refer to this.
You can read my answer how to start competitive programming CLICK HERE

Wednesday, May 18, 2016

How to Increase LAN bandwidth in college using SoftEther VPN and Dispatch proxy

How to Increase LAN bandwidth/Speed in college using SoftEther VPN and Dispatch proxy.

How to Increase LAN bandwidth in college using SoftEther VPN and Dispatch proxy


  1. Download & Install SoftEther VPN Client.
  2. Download & Install SoftEther VPN Server.
  3. Download & Install Node JS.
  4. Install Dispatch Proxy
  5. Open CMD and Run following Command :- npm install -g dispatch-proxy

Initial Server Setup

  1. Open SoftEther VPN Server and Click on Connect
  2. After that click in Local Bridge Setting
  3. Write DEFAULT in Virtual Hub row & Select your Ethernet card from LAN Adapter dropdown
  4. After Creating Local Bridge it should look like:-

Client Side setup

  1. Open SoftEther VPN Client and Create New Virtual Network Adapter..
  2. Leave As it is - Virtual Network Adapter Name (It will automatically take Unique Name)
  3. After Creating Virtual Network Adapter It should look like.
  4. Now Double Click on Add VPN Connection
    1. After Opening of new pannel write localhost in host name field.
    2. Now Just Click on corresponding VPN client adapter. Eg:- If setting name is "New VPN Connection (2)" then select "VPN Client Adapter - VPN2" for simplicity. Other Wise you can change the name of setting and corresponding Virtual Network Adapter.
      For Every New VPN connection Select Virtual Network Which were not Previously Used.
    3. Now Under "User Authentication Setting" Set "Auth Type:" to - Anonymous Authentication.
      Set the "User Name" Whatever you want and remember that name.
      You Should Give Unique User Name Each Time You Create a New VPN Connection.

      For Simplicity Give Name Like "vpn1" , "vpn2". It will be easy to Remember.

    After Doing All Above Steps You have to Add Users in VPN Server Manager

Adding Users in SoftEther VPN Server Manager

  1. Open SoftEther VPN Server Manager and Click on Connect Button.
  2. After that Click on Manage Virtual Hub Button.
  3. Now Click on Manage Users Button.
  4. After that Click on New Button.
  5. Now In the "User Name" Field Write the Name which You have Written in Step 4.3 of "Client Side Setup" Part & Set the Auth Type to Anonymous Authentication. & Click Ok Button
  6. After Doing All the Above Steps it Should Look Like.
  7. After All Above Step Close All SoftEther Server Manager Windows

Connection Between Client & Server

  1. Open SoftEther VPN Client Manager & Right Click on VPN Connection Which You Want To Connect and Then Click Connect.

Setting Up IP Address of VPN Adapters

  1. First You have to Know the Default Gateway , Subnet Mask & DNS Server Address of You LAN.

    1. Open CMD and Type ipconfig & Find "Ethernet adapter Ethernet:" and from there Note Down Default Gateway , Subnet Mask.
    2. For DNS Servers Write & . These are DNS Server Hosted by Google.
  2. Open Network and Sharing Center , It Should Look Like Below Image . Now Click on VPN Connection Name
  3. A dialoge Box Like Below Image will Pop Up , Now Click On Properties.
  4. After That a New Pop Like below Image will Pop up, Now Double Click on "Internet Protocol Version 4(TCP/IP)" (if You are using Ipv6 the select Ipv6 from menu) Or Select Ipv4 and Click on Properties.
  5. Now Fill the Default Gateway , Subnet Mask , and any IP address which Belong to Your Network & Fill DNS Server Address as given in below Image. And Click OK Button
    Eg:- In below Image I have Shown My configuration , Your Might be different.
  6. After Doing all above steps your VPN network name should lie under Column Where Access Type is Internet. (Sorry I couldn't show you here exactly)

Starting Dispatch Proxy

  1. Open CMD and Run Command :- dispatch start For Socks V5 Proxy or dispatch start --http for HTTP proxy and Leave it Running.
  2. After Doing above steps you are set to go. Use the proxy server :- localhost & port 1080 In any Download manager. You can only use this proxy if you are using any threaded Download Manager such and IDM , XDM etc. Below Image Shows Proxy Setting in IDM.

Things To be kept in Mind

  1. If You add N VPN Connection and use N Connection in IDM them you Download speed will increase by N time your current download speed.
    Connection Seeting For IDM is Shown in Below Image.
  2. This is Processer Intensive Task If you make Higher number of connection ( >10 )You system might Hang.
  3. For Adding More VPN connections Repeat Steps of Client Side setup , Adding Users in SoftEther VPN Server Manager , Connection Between Client & Server , Setting Up IP Address of VPN Adapters Blocks.
  4. I get 4 to 6 MB/ps speed by using 15 to 17 connections on ISM LAN , Whereas in ISM we get generally 100-150KB/ps.