Routing

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Router It is a device used to communication between two different networks. Routing It is process of sending the data packets through the best path to reach the destination. Default Gateway It gives the exit point (or) entry point to reach the destination.

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Use of Routing and Remote Access Service in Windows Server 2003

Routing and Remote Access is a service that performs

routing

as

one

processes.

of

its

multiple

Software Software Router Router

LAN

LAN

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What is Network Address Translation ?

Provides access to the Internet from a protected private address range Translates Private IP s to Public IP s & vice-versa for outgoing and incoming traffic Hides private IP address range from the Internet Can be used with DHCP or can be configured to assign IP to Client

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How NAT Works? Client Computers

Internet Computer Running NAT Internal IP = 10.0.0.1 External IP = 202.153.32.1

Web Server IP = 66.11.10.12

IP = 10.0.0.3

IP = 10.0.0.4 1. The client sends the packet to the computer running NAT 2. The computer running NAT changes the packet header and sends the packet over the Internet to the Web server IP = 10.0.0.5

3. The Web server sends a reply to the computer running NAT 4. The computer running NAT determines the destination, changes the packet header, and sends the packet to the client

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What Is a DHCP Relay Agent?

A DHCP Relay agent is a computer or router that listens for DHCP Broadcasts from DHCP clients and then relays those messages to DHCP Servers.

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How a DHCP Relay Agent Works

DHCP DHCP Server Server Router Router && DHCP DHCP Relay Relay Agent Agent Client1 Client1

1 2 3 4 5 6 7 8

Client2 Client2

Client3 Client3

Client1 Client1 broadcasts broadcasts a DHCPDISCOVER DHCPDISCOVER packet packet Relay Relay agent agent forwards forwards the the DHCPDISCOVER DHCPDISCOVER message message to to the the DHCP DHCP server server Server Server sends sends aa DHCPOFFER DHCPOFFER message message to to the the DHCP DHCP relay relay agent agent Relay Relay agent agent broadcasts broadcasts the the DHCPOFFER DHCPOFFER packet packet Client1 Client1 broadcasts broadcasts a DHCPREQUEST DHCPREQUEST packet packet Relay Relay agent agent forwards forwards the the DHCPREQUEST DHCPREQUEST message message to to the the DHCP DHCP server server Server Server sends sends aa DHCPACK DHCPACK message message to to the the DHCP relay relay agent agent Relay Relay agent agent broadcasts broadcasts the the DHCPACK DHCPACK packet packet

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