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Building Small Office Topology to configure DNS, Web Server, NAT by using Cisco Packet Tracer

- By Pravin Shinde

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Cisco Packet Tracer

  • Packet Tracer is a cross platform visual simulation tool designed by Cisco Systems  that allows users to create network topologies and imitate modern computer networks. 
  • The software allows users to simulate the configuration of Cisco routers and switches using a simulated command line interface.
  • Packet Tracer can be run on Linux, Microsoft Windows, and macOS.
  • Packet Tracer supports an array of simulated Application Layer protocols, as well as basic routing with RIP, OSPF, EIGRP, BGP.
  •  As of version 5.3, Packet Tracer also supports the Border Gateway Protocol.

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Problem: - Shortage of IPV4 address

  • Theoretically, IANA have 4,294,967,296 unique addresses (2 raised to 32). The actual number of available addresses is smaller (somewhere between 3.2 and 3.3 billion) because of the way that the addresses are separated into classes, and because some addresses are set aside for multicasting, testing or other special uses.

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  • With the explosion of the Internet and the increase in home networks and business networks, the number of available IP addresses is simply not enough. The obvious solution is to redesign the address format to allow for more possible addresses. This is being developed (called IPv6) but will take several years to implement because it requires modification of the entire infrastructure of the Internet.

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Solution: - NAT

  • Network Address Translation allows a single device, such as a router, to act as a gateway between the Internet (or "public network") and a local (or "private") network.
  • This means that only a single, unique IP address is required to represent an entire group of computers.

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Some benefits of NAT include: -�

  • Reuse of private IP addresses
  • Enhancing security for private networks by keeping internal addressing private from the external network
  • Connecting a large number of hosts to the global Internet using a smaller number of public (external) IP address, thereby conserving IP address space

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Topology

End Device

Access Layer Switch

Distribution Switches

Core Device

Edge Router

NAT

Public Network

Private Network

DNS Server

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