20+ TCS Network Administrator Interview Questions and Answers

Interview questions for Network Administrator role

• Architecture of Firewalls

• Previous role & responsibilities

• Troubleshooting end-user website/server access issues

• Handling latency issues

• Exceptional cases in firewall troubleshooting

• Understanding 3-way handshake

• HSRP and its feasibility with different geolocations

• TCP vs UDP differences

• Understanding ISO OSI model

Static routing uses manually configured routes while dynamic routing uses protocols to automatically update routes.

• Static routing requires manual configuration of routes while dynamic routing uses protocols to automatically update routes.

• Static routing is best suited for small networks with few changes while dynamic routing is better for larger networks with frequent changes.

• Examples of static routing protocols include OSPF and BGP while examples of dynamic routing protocols ...read more

Unicast, multicast and broadcast are types of network communication.

• Unicast is a one-to-one communication between a sender and a receiver.

• Multicast is a one-to-many communication where a sender sends data to a group of receivers.

• Broadcast is a one-to-all communication where a sender sends data to all devices on the network.

• Unicast is used for communication that requires privacy and security.

• Multicast is used for streaming media, video conferencing, and online gaming.

• Broadcast...read more

OSPF has three layers: backbone, area, and interface.

• Backbone layer connects all areas and is responsible for routing between them.

• Area layer groups networks together and reduces the amount of routing information exchanged.

• Interface layer connects routers to the network and exchanges routing information within an area.

• OSPF uses a hierarchical structure to efficiently manage large networks.

• Each layer has its own set of rules and protocols for communication and routing.

• Example:...read more

TCP is a connection-oriented protocol while UDP is a connectionless protocol.

• TCP provides reliable, ordered, and error-checked delivery of data while UDP does not guarantee reliable delivery.

• TCP is slower but more reliable while UDP is faster but less reliable.

• TCP is used for applications that require high reliability and accuracy while UDP is used for applications that require speed and efficiency.

• Examples of TCP-based applications include email, file transfer, and web brows...read more

NAT stands for Network Address Translation. It is a technique used to map public IP addresses to private IP addresses.

• NAT is used to conserve public IP addresses by allowing multiple devices to share a single public IP address.

• It provides an additional layer of security by hiding the private IP addresses of devices on a network.

• There are three types of NAT: Static NAT, Dynamic NAT, and Port Address Translation (PAT).

• Static NAT maps a single private IP address to a single publ...read more

Static routing is a type of network routing where the administrator manually configures the routes in the routing table.

• Routes are manually configured by the network administrator

• Routes do not change unless manually modified

• It is less flexible than dynamic routing

• It is useful for small networks with few changes in topology

• Example: A small office network with a single router connecting to the internet

Routing is the process of selecting the best path for network traffic to reach its destination.

• Routing involves analyzing network topology and determining the most efficient path for data to travel.

• Routers use routing tables to determine the best path for data to take.

• Routing protocols such as OSPF and BGP are used to exchange routing information between routers.

• Routing can be either static or dynamic, depending on whether the routing table is manually configured or automatic...read more

IP stands for Internet Protocol, a set of rules governing the format of data sent over the internet. OSI layers refer to the Open Systems Interconnection model, a conceptual framework used to understand how different networking protocols interact.

• IP (Internet Protocol) is a set of rules that governs the format of data sent over the internet.

• OSI (Open Systems Interconnection) layers refer to a conceptual framework that helps understand how different networking protocols intera...read more

The implementation of a new device in a network involves planning, testing, and deployment to ensure seamless integration.

• Plan the implementation process, including assessing network compatibility and potential impact on existing devices.

• Test the new device in a controlled environment to identify any issues or conflicts before full deployment.

• Deploy the new device during off-peak hours to minimize disruption to network operations.

• Monitor the network after implementation to en...read more

Firewall policies can be configured by defining rules to control incoming and outgoing network traffic.

• Identify the network traffic that needs to be controlled

• Create rules based on IP addresses, ports, protocols, and applications

• Prioritize rules to ensure proper traffic flow

• Regularly review and update firewall policies to adapt to changing network needs

NAT is used to translate private IP addresses to public IP addresses, allowing multiple devices to share a single public IP address.

• Allows multiple devices on a local network to access the internet using a single public IP address

• Enhances security by hiding internal IP addresses from external networks

• Conserves public IP addresses by allowing multiple devices to share a single public IP address

DNS stands for Domain Name System, it translates domain names to IP addresses.

• DNS is like a phone book for the internet, translating domain names (like google.com) to IP addresses (like 172.217.3.206)

• DNS works by sending queries to DNS servers, which then look up the corresponding IP address for the requested domain

• DNS also helps with load balancing and redundancy by allowing multiple IP addresses to be associated with a single domain name

Types of VPNs include remote access VPN, site-to-site VPN, and client-to-site VPN.

• Remote access VPN allows individual users to connect to a private network from a remote location

• Site-to-site VPN connects entire networks together over the internet

• Client-to-site VPN allows individual clients to connect to a private network

MPLS configuration involves setting up labels, routes, and protocols for efficient data transmission.

• Configure MPLS on routers by enabling MPLS forwarding

• Assign labels to packets to determine their path through the network

• Set up LDP or RSVP-TE protocols for label distribution

• Implement MPLS VPNs for secure communication between different networks

VPN stands for Virtual Private Network. Protocols are rules that govern data transmission over a network.

• VPN allows users to securely access a private network over a public network like the internet

• Protocols are sets of rules that determine how data is transmitted between devices

• Common VPN protocols include OpenVPN, L2TP/IPsec, and PPTP

VPN stands for Virtual Private Network, a secure connection that allows users to access a private network over a public network.

• VPN creates a secure and encrypted connection over the internet

• It allows users to access resources on a private network from a remote location

• Commonly used for remote work, accessing company files securely, and bypassing geo-restrictions

• Examples include OpenVPN, Cisco AnyConnect, and NordVPN

BGP stands for Border Gateway Protocol, a routing protocol used to exchange routing information between different networks on the internet.

• BGP is used to make routing decisions based on network policies, rules, and path preferences.

• It is commonly used by Internet Service Providers (ISPs) to connect their networks and exchange routing information.

• BGP operates on the application layer of the OSI model.

• BGP helps in determining the best path for data to travel between networks.

• An...read more

ACL stands for Access Control List, which is a set of rules that controls network traffic and permissions on a network device.

• ACL is used to filter network traffic based on defined criteria such as source or destination IP address, port number, protocol, etc.

• ACL can be configured on routers, switches, firewalls, and other network devices to control access to resources.

• There are two types of ACLs: standard ACLs and extended ACLs.

• Example: In a router configuration, an ACL can b...read more

Switching is the process of forwarding data packets between devices on a network based on the destination address.

• Switching occurs at the data link layer of the OSI model.

• Switches use MAC addresses to determine where to forward incoming data packets.

• Switching is faster and more efficient than traditional hub-based networking.

• Examples of switches include Cisco Catalyst series and Juniper EX series.