A Distributive Server

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A Distributive Server

• Alberto Pareja-Lecaros

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Introduction

• Uses of distributive computing
• - High powered applications
• - Ever-expanding server so theres never a limit
• - Speed
• RMI, JAAS, Kerberos will be used exclusively with
  JAVA

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JAAS (JAVA Authentication and Authorization
Service)
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Authentication

• Check client exists
• Make sure client has sufficient access
  (passwords, etc.)

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Authorization

• Determine credentials of authenticated client
  (permissions, etc.)
• Allow client access only to what it has
  permission to access
• Sample shows allowing to find java.home property,
  root.home property, and allowing to determine
  whether a file exists in the directory

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Why useful?

• JAAS uses security protocol Kerberos
• Allows for different users with different access
  (admins, regular users)
• Allows the banning of users

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RMI (Remote Method Invocation)
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Whats RMI?

• Allows remote execution of code
• Provides security of code
• Provides for permissions needed to access the code

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Why Useful?

• Allows clients to become servers by executing
  remote server code (essential for distributive
  computing)
• Allows execution to be done in a secure
  environment
• Integrated into JAVA so its easy to use

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RMI vs Serializing over the stream

• RMI is much faster
• No huge chunks of data are being sent over the
  network
• No copies of objects, objects are accessed
  remotely
• Serializing has its problems

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Kerberos
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Whats Kerberos?

• Quite simply, its a security protocol
• Allows for protection of clients/servers
• Keeps sensitive information encrypted and never
  stored/transmitted

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Why useful?

• Helps prevent hacking into the client/server
• Allows for safe connections using JAAS
• Provides safety when allowing clients to access
  remote code with RMI

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Results so far

• One connection to server per client
• Set permissions of clients via a permission file
• Never send passwords over a stream (Let Kerberos
  encrypt it)
• Main server holds all information and relays
  clients to their designated server (determined by
  the main server)
• Clients only connect to the main server directly

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Current design

• Game Client connects to a Game Server
• A Main Server keeps track of all Game Servers in
  a Server Map.
• Game Servers listen for Game Clients and connects
  them
• Game Clients send objects called Messages which
  tells the Server what to execute
• The Server sends back any execution results

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Messages

• Objects containing different types of data for
  the server to interpret
• Server takes these messages and executes them
  depending on the message type

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Darkstar

• A new client/server library released by Sun
• Connections handled transparently
• Different levels of security (authorization,
  authentication, etc.)
• Fast, reliable way of handling client server
  applications
• Extremely new library (3/28/06) and will be
  implemented to speed up design