Telnet lets you manage Cisco switches and routers remotely however it is not very secure. This article explains how to disable Telnet on Cisco devices
Cisco IOS Router commands cheat sheet - Contains quick reference and basic IOS commands for Cisco IOS Router.
How to configure SSH on Cisco Router and Switches. Enabling SSH allow you to securely manage Cisco devices remotely.
Cisco IOS Switch commands cheat sheet - Contains quick reference and basic IOS commands for Cisco IOS Switch.
Configuring port security on Cisco IOS switch by setting violation mode, max MAC addresses, aging and static MAC addresses
This article tells you how to configure a Cisco Router as DHCP server. Explains the IOS commands for configuring the router as DHCP server
how to view IP routing table and add or remove static IP routes in Windows.
This article describes how to restrict management access on Juniper SRX device to specific network addresses by setting up a firewall filter