10+ TAC Engineer Interview Questions and Answers

RSTP BPDU introduces two new flags: TCN and Proposal.

• TCN (Topology Change Notification) flag is used to indicate a topology change in the network.

• Proposal flag is used to speed up the convergence process by allowing a switch to immediately transition to the forwarding state.

• TCN flag is set by the root bridge and propagated to all switches in the network.

• Proposal flag is set by a switch and sent to the root bridge.

• Both flags are included in the BPDU message.

• TCN flag triggers a...read more

To troubleshoot SSH issue, check network connectivity, firewall settings, SSH configuration, and user permissions.

• Check if the server is reachable over the network

• Verify if the SSH service is running on the server

• Check if the firewall is blocking SSH traffic

• Verify SSH configuration on the server

• Check if the user has the necessary permissions to access the server

• Check SSH logs for any errors or warnings

When you type google.com on your web browser, it sends a request to Google's server and loads the website.

• The browser sends a DNS request to resolve the domain name 'google.com' to an IP address

• The browser establishes a TCP connection with Google's server

• The browser sends an HTTP request to the server for the homepage of google.com

• The server responds with the HTML code for the homepage

• The browser renders the HTML code and displays the webpage

Motivating a customer on escalation edge

• Show empathy and understanding of their frustration

• Provide regular updates on the progress of the case

• Offer solutions or workarounds to mitigate the issue

• Highlight the importance of resolving the issue for their business

• Escalate the case to higher management if necessary

• Thank them for their patience and cooperation

TCP 3-way handshake is a process of establishing a connection between two devices. SSL handshake is a process of establishing a secure connection between a client and a server.

• TCP 3-way handshake involves SYN, SYN-ACK, and ACK packets exchanged between the client and server to establish a connection.

• SSL handshake involves exchanging certificates, negotiating encryption algorithms, and generating session keys.

• TCP 3-way handshake is used in TCP/IP protocol, while SSL handshake ...read more

Explanation of Spanning Tree Protocol and troubleshooting techniques for switching networks.

• Spanning Tree Protocol (STP) is used to prevent loops in a network by blocking redundant paths.

• Troubleshooting STP involves checking for blocked ports, incorrect root bridge selection, and misconfigured priority values.

• Other common issues in switching networks include VLAN mismatches, port security violations, and broadcast storms.

• Tools such as packet captures, show commands, and netwo...read more

Hub operates at physical layer, broadcasts data to all ports. Switch operates at data link layer, forwards data to specific ports.

• Hub operates at physical layer, broadcasts data to all ports

• Switch operates at data link layer, forwards data to specific ports

• Hub is less secure as it broadcasts data to all ports

• Switch is more secure as it forwards data only to specific ports based on MAC addresses

DORA process is a four-step process used by DHCP to assign IP addresses to devices on a network.

• DORA stands for Discover, Offer, Request, and Acknowledge.

• Discover: The device sends a broadcast message to find available DHCP servers.

• Offer: The DHCP server responds with an IP address offer.

• Request: The device requests the offered IP address.

• Acknowledge: The DHCP server acknowledges the request and assigns the IP address to the device.

• DORA process ensures efficient IP address as...read more

My biggest achievement was successfully leading a team to implement a new network infrastructure, overcoming technical challenges along the way.

• Led a team to implement a new network infrastructure

• Overcame technical challenges during the project

• Achieved successful implementation within the set timeline and budget

I handle customers with patience, empathy, and effective communication.

• Listen actively to their concerns and needs

• Acknowledge their frustrations and apologize for any inconvenience

• Provide clear and concise solutions to their problems

• Follow up with them to ensure their issue has been resolved

• Maintain a positive and professional attitude throughout the interaction

Packet tracer real life scenario involves simulating network configurations and troubleshooting issues in a virtual environment.

• Create a network topology with routers, switches, and end devices

• Configure IP addresses, VLANs, routing protocols, and access control lists

• Simulate network traffic and troubleshoot connectivity issues

• Use tools like ping, traceroute, and Wireshark to analyze network traffic

ARP (Address Resolution Protocol) is used to map IP addresses to MAC addresses on a local network.

• ARP is used to find the MAC address of a device based on its IP address.

• ARP requests are broadcasted on the local network to all devices.

• Once the device with the corresponding IP address responds, its MAC address is stored in the ARP table.

• ARP cache poisoning is a common attack where a malicious device sends false ARP messages to redirect traffic.

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

• The OSI model stands for Open Systems Interconnection model.

• It helps in understanding how different networking protocols work together.

• Each layer has a specific function and communicates with the layers above and below it.

• Examples of layers include physical layer, data link layer, network layer, transport layer, session layer, presenta...read more

Switch vlan brief command displays a summary of VLAN information on a switch.

• Used to quickly view VLAN configuration on a switch

• Shows VLAN ID, name, status, and ports assigned to each VLAN

• Helps troubleshoot VLAN-related issues

• Example: 'switch vlan brief' command on Cisco switches

DNS flow refers to the process of how a DNS query is resolved from start to finish.

• Client sends a DNS query to the recursive resolver.

• Recursive resolver checks its cache for the answer, if not found, it sends the query to authoritative nameservers.

• Authoritative nameservers respond with the IP address of the requested domain.

• Recursive resolver caches the response and sends it back to the client.

• Client now has the IP address and can connect to the requested domain.

TCP flow refers to the sequence of packets exchanged between two devices over a TCP connection.

• TCP flow involves the establishment, data transfer, and termination of a TCP connection.

• It includes the exchange of TCP segments containing data, acknowledgment, and control information.

• TCP flow control mechanisms like sliding window and congestion control help regulate the flow of data.

• TCP flow can be analyzed using tools like Wireshark to troubleshoot network issues.