100+ 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

L2 VPN operates at the data link layer, while L3 VPN operates at the network layer.

• L2 VPN provides layer 2 connectivity between remote sites, while L3 VPN provides layer 3 connectivity.

• L2 VPN uses MAC addresses for forwarding, while L3 VPN uses IP addresses.

• L2 VPN is typically used for connecting LANs, while L3 VPN is used for connecting networks.

• L2 VPN is transparent to the network layer protocols, while L3 VPN requires routing protocols.

• Examples of L2 VPN technologies inclu...read more

To link up two routers with OSPF enabled but link down, specific methods include checking physical connections, verifying OSPF configurations, and troubleshooting network issues.

• Check physical connections and ensure cables are properly connected and not damaged

• Verify OSPF configurations and ensure that the routers are configured with the same OSPF process ID and network type

• Troubleshoot network issues by checking for any network outages or misconfigurations

• Use tools such as p...read more

Answers to questions related to network administration including firewall, NAT control, OSI, TCP flags, VPN and encryption techniques.

• Post 8.2 firewall versions have improved features and security compared to pre 8.2 versions

• NAT control is a feature that allows or denies traffic based on NAT rules

• S NAT is a type of NAT that translates the source IP address of a packet and persistence in F5 refers to maintaining a client's connection to a specific server

• OSI works by breaking d...read more

A network is a group of interconnected devices that communicate with each other. An IP address is a unique identifier assigned to each device on a network.

• A network is a collection of devices such as computers, printers, and servers that are connected to each other.

• An IP address is a unique identifier assigned to each device on a network to enable communication between devices.

• The range of an IP address is determined by the subnet mask, which specifies the number of bits used...read more

STP, HSRP, and FRRP are network protocols used for redundancy and failover. HSRP and VRRP are similar but HSRP is preferred.

• STP (Spanning Tree Protocol) prevents loops in a network by disabling redundant links

• HSRP (Hot Standby Router Protocol) and VRRP (Virtual Router Redundancy Protocol) provide redundancy by allowing multiple routers to share a virtual IP address

• FRRP (Fast Router Redundancy Protocol) is a Cisco proprietary protocol that provides faster failover than HSRP an...read more

I am interested in joining interworking and desktop support because of my passion for troubleshooting and helping others with their technical issues.

• I enjoy problem-solving and finding solutions to technical issues

• I have experience in desktop support and enjoy working with end-users

• I am interested in learning more about interworking and network administration

• I believe my skills and experience would be a good fit for this role

To route between two VLANs in a switch LAN network, you can use a Layer 3 switch or a router.

• Configure inter-VLAN routing on a Layer 3 switch by creating SVIs (Switch Virtual Interfaces) for each VLAN and enabling routing.

• Use a router to route between VLANs by connecting the router to the switch and configuring subinterfaces on the router for each VLAN.

• Implement VLAN trunking between the switch and the router to carry traffic for multiple VLANs over a single link.

• Ensure that ...read more

2 out of 5 pool members are down in F5 bigip load balancer.

• The load balancer is currently using the 3 available pool members to distribute traffic.

• The 2 down pool members need to be fixed or removed from the pool to prevent traffic from being directed to them.

• The load balancer should be monitored to ensure that it is functioning properly and distributing traffic evenly.

• If necessary, additional pool members can be added to the pool to handle increased traffic or to provide red...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

MPLS is a protocol used to speed up and shape network traffic. VRFs allow multiple virtual networks to coexist on a single physical network. CEF is a forwarding mechanism used in MPLS. Routing protocols are used to exchange routing information between routers.

• MPLS stands for Multiprotocol Label Switching and is used to improve network performance by reducing the time it takes for packets to travel through a network.

• VRFs (Virtual Routing and Forwarding) allow multiple virtual ...read more

BGP attributes used for controlling inbound & outbound traffic are Local Preference, AS Path, and MED.

• Local Preference: Used to influence the path selection within an autonomous system (AS). Higher value means preferred route.

• AS Path: Specifies the ASes that the route has traversed. Shorter AS Path is preferred.

• MED (Multi-Exit Discriminator): Used to influence the path selection between different ASes. Lower MED is preferred.

To add a system in domain with DNS error, first resolve the DNS issue and then add the system to the domain.

• Check the DNS settings and ensure they are correct

• Verify that the DNS server is running and accessible

• Flush the DNS cache on the system

• If necessary, add a static DNS entry for the domain controller

• Once the DNS issue is resolved, add the system to the domain as usual

The xlate table in ASA is used to keep track of translations between internal and external IP addresses. It is important for IPsec tunnel troubleshooting.

• The xlate table is used to map internal IP addresses to external IP addresses

• It is important for troubleshooting IPsec tunnels because it allows you to see if traffic is being translated correctly

• You can view the xlate table using the 'show xlate' command in the ASA CLI

• If there are issues with the xlate table, it can cause I...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

Different cable types have different supported speeds, such as Cat5e supporting up to 1 Gbps and Cat6 supporting up to 10 Gbps.

• Cat5e - supports up to 1 Gbps

• Cat6 - supports up to 10 Gbps

• Cat6a - supports up to 10 Gbps at longer distances

• Fiber optic cables - support much higher speeds than copper cables

You can directly connect the server and laptop using a crossover Ethernet cable.

• Use a crossover Ethernet cable to connect the server's network interface card (NIC) to the laptop's NIC.

• Assign static IP addresses to both the server and laptop in the same subnet.

• Configure the network settings on both devices to ensure they are on the same network.

• Test the connection by pinging the server from the laptop to verify connectivity.

Multiple firewalls with Palo Alto offer advanced security features compared to past experiences.

• Palo Alto firewalls offer advanced threat prevention capabilities such as URL filtering, antivirus, and intrusion prevention.

• Multiple firewalls can be configured to work together to provide high availability and load balancing.

• Past experiences may have involved less advanced firewalls with limited capabilities.

• Palo Alto firewalls also offer centralized management and reporting thro...read more

NAT and PAT are both techniques used in networking to translate IP addresses. NAT translates one IP address to another, while PAT translates multiple IP addresses to a single IP address.

• NAT stands for Network Address Translation and is used to translate private IP addresses to public IP addresses.

• PAT stands for Port Address Translation and is a type of NAT that translates multiple private IP addresses to a single public IP address using different port numbers.

• NAT is typically...read more

RIP and OSPF are routing protocols used in computer networks.

• RIP is a distance-vector protocol while OSPF is a link-state protocol.

• RIP uses hop count as the metric while OSPF uses cost.

• OSPF supports VLSM and CIDR while RIP does not.

• OSPF is more scalable and efficient for larger networks than RIP.

• RIP broadcasts its routing table updates while OSPF uses multicast.

• OSPF has a faster convergence time than RIP.

• RIP is simpler to configure and troubleshoot than OSPF.

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

Catalyst 5000 uses shared memory LAN switching.

• Catalyst 5000 uses a shared memory architecture for LAN switching.

• This allows for high-speed switching between ports.

• The shared memory architecture also allows for advanced features like VLANs and QoS.

• Examples of Catalyst 5000 models include the 5500 and 5002.

• These switches were popular in the 1990s and early 2000s.

VLAN is used to segment network traffic, while voice VLAN is used to prioritize voice traffic.

• VLAN is used to separate network traffic into different virtual networks.

• Voice VLAN is a feature that allows voice traffic to be prioritized on the network.

• Commands like 'switchport mode access' and 'switchport voice vlan' are used to configure VLAN and voice VLAN access.

Switch forwards data within a network based on MAC addresses, router forwards data between networks based on IP addresses, L3 switch combines features of both.

• Switch operates at Layer 2 of the OSI model, forwarding data based on MAC addresses.

• Router operates at Layer 3, forwarding data between different networks based on IP addresses.

• L3 switch combines features of both switch and router, capable of routing based on IP addresses while also performing switching functions at Lay...read more

HTTP is unsecured protocol while HTTPS is secured protocol using SSL/TLS encryption.

• HTTP stands for Hypertext Transfer Protocol, while HTTPS stands for Hypertext Transfer Protocol Secure.

• HTTP operates on port 80, while HTTPS operates on port 443.

• HTTP does not encrypt data, while HTTPS encrypts data using SSL/TLS.

• HTTPS provides authentication and data integrity along with encryption.

• Websites using HTTPS have a padlock icon in the address bar to indicate a secure connection.

Service tickets are used to request support for an existing service, while change tickets are used to request changes to a service.

• Service tickets are reactive, while change tickets are proactive.

• Service tickets are used to restore a service to its normal state, while change tickets are used to improve or modify a service.

• Service tickets are typically handled by the service desk, while change tickets are typically handled by change management.

• Examples of service tickets inclu...read more

Virtual servers are software-based while nodes are physical devices.

• Virtual servers are created by partitioning a physical server into multiple virtual machines.

• Nodes are individual physical devices that are connected to a network.

• Virtual servers can be easily created, cloned, and deleted while nodes require physical installation and configuration.

• Virtual servers can be easily moved between physical servers while nodes cannot.

• Examples of virtual server software include VMware...read more

DHCP is a network protocol that automatically assigns IP addresses to devices. Network topology refers to the layout of a network.

• DHCP stands for Dynamic Host Configuration Protocol

• DHCP automatically assigns IP addresses to devices on a network

• Network topology refers to the physical or logical layout of a network

• Common network topologies include star, bus, ring, and mesh

LAN is a local network while WAN is a wide area network.

• LAN is limited to a small geographical area such as a home, office, or building

• WAN covers a larger geographical area such as a city, country, or even the world

• LAN typically has higher data transfer rates and lower latency compared to WAN

• Examples of LAN include home networks, office networks, and school networks

• Examples of WAN include the internet, cellular networks, and satellite networks

An iRule can be written to redirect a URI to a different location.

• Use the HTTP::redirect command to specify the new URI

• Use the HTTP_REQUEST event to trigger the iRule

• Example: when HTTP_REQUEST {HTTP::redirect "http://newlocation.com"}

RSTP, STP, and MSTP are all protocols used for preventing network loops, but they differ in their speed and complexity.

• STP (Spanning Tree Protocol) is the original protocol used for preventing network loops.

• RSTP (Rapid Spanning Tree Protocol) is an updated version of STP that is faster and more efficient.

• MSTP (Multiple Spanning Tree Protocol) is a more complex protocol that allows for multiple VLANs to be mapped to a single spanning tree instance.

• RSTP is faster than STP becau...read more

Cisco ASA Firewall uses failover to ensure high availability and uninterrupted network services.

• Failover is the process of switching to a backup device in case of a failure in the primary device.

• Cisco ASA Firewall supports two types of failover: Active/Standby and Active/Active.

• In Active/Standby failover, one firewall is active and the other is in standby mode, ready to take over in case of a failure.

• In Active/Active failover, both firewalls are active and share the traffic l...read more

VLAN in switching separates broadcast domains, site-to-site VPN connects two remote networks securely, routing directs traffic between networks.

• VLAN stands for Virtual Local Area Network and is used to separate broadcast domains within a network switch.

• Site-to-site VPN allows secure communication between two remote networks over the internet.

• Routing is the process of directing network traffic between different networks based on IP addresses.

• Examples: VLANs can be used to sepa...read more

Spectra Technovision India is a technology company based in India.

• Spectra Technovision India provides IT solutions and services to various industries.

• The company specializes in software development, web development, and mobile app development.

• Spectra Technovision India also offers digital marketing services and IT consulting.

• Some of their clients include HDFC Bank, ICICI Bank, and Tata Motors.

DHCP stands for Dynamic Host Configuration Protocol. It is a network protocol that automatically assigns IP addresses to devices on a network.

• DHCP is used to manage and distribute IP addresses in a network

• It allows devices to obtain IP addresses dynamically instead of manually configuring them

• DHCP also provides other network configuration information like subnet mask, default gateway, and DNS server addresses

• MAC (Media Access Control) address is a unique identifier assigned t...read more

The OSI model is a conceptual framework that standardizes the functions of a telecommunication or computing system into seven layers.

• OSI model stands for Open Systems Interconnection model

• It consists of 7 layers: Physical, Data Link, Network, Transport, Session, Presentation, Application

• Switching is a method used to forward data packets between devices on a network

• Routing is the process of selecting the best path for data packets to travel from one network to another

• HSRP (Hot...read more

HSRP, VRRP, and GLBP are all protocols used for providing redundancy in a network.

• HSRP stands for Hot Standby Router Protocol and is a Cisco proprietary protocol.

• VRRP stands for Virtual Router Redundancy Protocol and is an open standard protocol.

• GLBP stands for Gateway Load Balancing Protocol and is also a Cisco proprietary protocol.

• HSRP and VRRP both provide redundancy by allowing multiple routers to share a virtual IP address.

• GLBP provides redundancy as well as load balanci...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

OSI stands for Open Systems Interconnection. It is a conceptual model that describes how data is transmitted over a network.

• OSI model has 7 layers, each with a specific function

• The layers are: Physical, Data Link, Network, Transport, Session, Presentation, and Application

• Each layer communicates with the layer above and below it

• The model helps ensure interoperability between different network devices and software

• Example: HTTP (Application layer) uses TCP (Transport layer) to s...read more

OSI is a theoretical model while TCP is a practical protocol.

• OSI has 7 layers while TCP has 4 layers.

• OSI is a reference model while TCP is a communication protocol.

• OSI is not implemented in practice while TCP is widely used.

• OSI is used for teaching and understanding while TCP is used for actual communication.

• Examples of OSI layers are physical, data link, network, transport, session, presentation, and application.

• Examples of TCP layers are network interface, internet, transpo...read more

Load sharing in BGP involves distributing traffic across multiple paths to optimize network performance.

• BGP allows for multiple paths to a destination to be advertised and stored in the routing table

• Load sharing can be achieved through equal cost multi-path (ECMP) or unequal cost multi-path (UCMP)

• ECMP distributes traffic evenly across multiple paths with the same cost

• UCMP distributes traffic across paths with different costs based on a configured ratio

• Load sharing can improve...read more

SSL offloading is a process of removing SSL encryption from incoming traffic and decrypting it before sending it to the backend servers.

• SSL offloading is performed by a load balancer like F5 to reduce the processing load on backend servers.

• It improves server performance and reduces latency by offloading SSL processing to a dedicated hardware or software.

• F5 SSL offloading can be configured to support multiple SSL certificates and protocols like TLS 1.3.

• It can also perform SSL ...read more

There are 6 flags in the TCP/IP protocol.

• The 6 flags in TCP/IP are: URG, ACK, PSH, RST, SYN, and FIN.

• These flags are used to control the flow of data and manage the connection between devices.

• For example, the SYN flag is used to establish a connection, while the FIN flag is used to terminate a connection.

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

Broadband and Leased Line are types of internet connections with different characteristics.

• Broadband is a high-speed internet connection that is always on and typically shared among multiple users.

• Leased Line is a dedicated connection between two points, providing consistent bandwidth and reliability.

• Broadband is suitable for residential use and small businesses, while Leased Line is preferred by large corporations for mission-critical applications.

• Broadband is usually cheape...read more

Yes

• As a Network Administrator, I can help resolve various technical issues in a hospital setting.

• Examples include troubleshooting network connectivity problems, resolving server issues, managing user accounts and permissions, ensuring data security, and implementing network upgrades.

• I can also assist in setting up and maintaining medical equipment that relies on network connectivity, such as patient monitoring systems or electronic health record systems.