Computer Networks

Computer Networks

Infrastructure, Systems, and Connectivity

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Articles in this Section

Hands-On Lab: Configuring Dynamic NAT

This hands-on lab configures dynamic NAT using a pool of public addresses, verifying that internal hosts are assigned public addresses from the pool on a first-come, first-served basis and that translations expire once idle.

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Hands-On Lab: Configuring PAT (NAT Overload)

This hands-on lab configures Port Address Translation using the overload keyword, allowing many internal hosts to share a single public IP address simultaneously, and verifies each host is distinguished by a unique translated port number.

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Hands-On Lab: Configuring a DHCP Server and DHCP Relay

This hands-on lab configures a router as a DHCP server for one subnet and configures DHCP relay (ip helper-address) so clients on a separate remote subnet can reach that same centralized server, verifying both scenarios independently.

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Hands-On Lab: Configuring NTP

This hands-on lab configures one router as an NTP server with a manually set clock and a second router as an NTP client synchronizing to it, verifying the client's clock converges to match the server over the network.

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Hands-On Lab: Configuring Syslog

This hands-on lab configures a router to send log messages to a centralized syslog server, sets an appropriate logging severity level, and verifies messages are actually received and correctly categorized on the server side.

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Hands-On Lab: Configuring SNMP

This hands-on lab configures SNMPv2c on a router with a read-only community string, verifies a management station can successfully poll device information, and covers why SNMPv3 is preferred for production environments requiring authentication and encryption.

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Hands-On Lab: Backing Up and Restoring Router Configuration Files

This hands-on lab backs up a router's running configuration to a TFTP server, deliberately makes an unwanted configuration change, and restores the router to its previous known-good state from the backup.

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Hands-On Lab: Upgrading Cisco IOS Using TFTP

This hands-on lab copies a new IOS image to a router's flash memory from a TFTP server, verifies sufficient flash space before starting, and points the boot system variable at the new image to make it load on next reload.

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Hands-On Lab: Password Recovery on a Cisco Router

This hands-on lab performs password recovery on a router with a lost or unknown enable secret, using ROMMON mode to bypass the startup configuration temporarily, reset the password, and restore normal operation with the original configuration intact.

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Hands-On Lab: Working with the Cisco IOS File System (IFS)

This hands-on lab explores the Cisco IOS File System commands used to navigate, list, and manage files across a router's different storage locations, including flash, NVRAM, and remote file systems referenced by URL-style prefixes.

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Hands-On Lab: Configuring SSH Access on a Router

This hands-on lab configures SSH for secure remote management on a router, generating an RSA key pair, requiring local authentication, and restricting VTY lines to SSH only, verifying Telnet access is completely disabled.

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Hands-On Lab: Configuring Local AAA Authentication

This hands-on lab configures the AAA framework on a router using the local username database, creating a custom authentication method list and applying it to the VTY lines, demonstrating a more flexible and scalable authentication approach than the login local command alone.

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