Overview: Password recovery is the process used to recover the enable password on a router. Configuration register can be used to change router behavior in different ways, but usually it’s to specify how it boots up. Study Notes: Password recovery procedures can be used to recover the enable password if it is unencrypted in […]
Overview: TFTP, FTP and SCP are protocols that can be used to upgrade and recover Cisco IOS images. Study Notes: Several protocols are available to copy the Cisco IOS image into a Cisco router. The most commonly used protocol is TFTP Other protocols include SCP and FTP MD5 is a way to verify the integrity […]
Overview: Initial device configuration is necessary when first powering on a new router or switch. It can be accomplished through the System Configuration Dialog guide or manually. Study Notes: When powering on a new device, the System Configuration Dialog will prompt you to continue with initial device configuration. Enter yes to continue being prompted […]
Overview: A loopback interface is a logical, virtual interface that is always up Study Notes: A loopback interface is a logical, virtual interface A loopback interface is always up/up once configured A loopback interface can be used to emulate a physical interface Any IP address can be assigned to a loopback interface Typically, a […]
Overview: When setting the correct time on a router, the first step is configuring the proper timezone Study Notes: By default, the timezone is UTC Configuring the correct time and timezone on a router are good practices for the following reasons Troubleshooting is simplified when log files display the correct time Multiple devices configured […]
Overview: Logging is essential to gaining visibility into your network Study Notes: By default, system logging is enabled to the console at the debugging level Log messages are displayed in this format Seq_no:timestamp: %facility-severity-MNEMONIC:description For example: 000052: Jan 20 08:50:18: %SYS-5-CONFIG_I: Configured from console by vty2 (172.16.0.25) Five types of logging Console logging – […]
Overview: CDP or LLDP can be used to discover details about neighboring devices Study Notes: CDP is covered in-depth in section 2.8.a: CDP LLDP is covered in-depth in section 2.8.b: LLDP To use CDP to discover neighboring devices, CDP must be enabled on both devices for neighbor information to be exchanged CDP is enabled […]
Overview: Backing up device configurations is good practice and can save a lot of downtime should a device need to be upgraded or swapped out. Study Notes: There are multiple ways to backup and restore configurations. TFTP and FTP are covered below. Use a TFTP server to backup a router configuration Start the […]
Overview: Syslog is a way for network devices to send event messages to a logging server, usually known as a Syslog server. Study Notes: Syslog – System Message Logging Syslog uses port 514 Controls the distribution of logging messages to various destinations based on the configuraiton Logging buffer Terminal lines Syslog server When disabled, […]
Overview: SNMPv2 improves upon the limitations in SNMPv1 Study Notes: SNMPv2 improves upon SNMPv1 (SNMPv1 was criticized for poor security) SNMPv2 includes these improvements Performance – GetBulkRequest in addition to the iterative GetNextRequest Security – party-based security system (obsoleted later due to complexity) Confidentiality Manager-to-manager communications SNMPv2 still uses the less secure community-string The […]