Tell me about yourself. * What is the OSI model? * What is the difference between TCP and UDP? * What is a VLAN? * What is the purpose of STP? * Explain the difference between a router and a switch. * What is subnetting? * What is DHCP? * What is DNS? * How would you troubleshoot a network outage? * What is NAT? * What is the difference between static and dynamic routing? * What is OSPF? * What is BGP? * What is the default gateway? * How do you check network connectivity? * Explain packet loss. * What is a firewall? * What is port security? * Describe a technical problem you solved.