20+ Senior Network Security Engineer Interview Questions and Answers

The question covers various topics related to ASA firewall, including security levels, differences between pre and post 8.3 versions, transparent and routed mode, VPN, stateful and stateless failover, and VPN commands.

• ASA firewall has security levels assigned to interfaces to control traffic flow

• The 8.3 version of ASA introduced significant changes in NAT configuration

• Transparent mode firewall operates at Layer 2 and doesn't modify IP addresses

• Routed mode firewall operates at...read more

Stateless firewall filters packets based solely on the information in the packet header, while stateful firewall keeps track of the state of active connections.

• Stateless firewall operates at the network layer and filters packets based on IP addresses and ports

• Stateful firewall operates at the session layer and keeps track of the state of active connections

• Stateful firewall can make decisions based on the context of the traffic, such as whether a packet is part of an establish...read more

Fortigate HA cluster is a high availability setup where two or more Fortigate devices work together to ensure continuous network security.

• Fortigate HA cluster involves setting up two or more Fortigate devices in an active-passive or active-active configuration.

• In active-passive setup, one device is active while the other is on standby, ready to take over in case of failure.

• In active-active setup, both devices actively process traffic and share the load.

• Heartbeat monitoring is...read more

Virtual router and virtual system play a crucial role in network security by providing isolated environments for routing and security policies.

• Virtual router is a software-based routing instance that operates within a virtualized environment.

• Virtual system is a logical division of a physical firewall that allows for separate security policies and configurations.

• Both virtual router and virtual system help in creating isolated network environments for better security and manage...read more

DDoS stands for Distributed Denial of Service. It is a type of cyber attack that aims to make a website or network unavailable to its users.

• DDoS attacks involve overwhelming a website or network with traffic from multiple sources, making it impossible for legitimate users to access it.

• Attackers use botnets, which are networks of compromised devices, to launch DDoS attacks.

• There are various types of DDoS attacks, including volumetric attacks, protocol attacks, and application ...read more

STP stands for Spanning Tree Protocol, which is used to prevent loops in a network by creating a loop-free logical topology.

• STP is a network protocol that ensures a loop-free topology in Ethernet networks.

• Types of STP include IEEE 802.1D (STP), IEEE 802.1w (Rapid STP), and IEEE 802.1s (Multiple STP).

• STP works by electing a root bridge and blocking redundant paths to prevent loops.

• STP convergence time can be improved with Rapid STP and Multiple STP variants.

OSPF (Open Shortest Path First) is a routing protocol used to find the best path for data packets in a network.

• OSPF is a link-state routing protocol

• It uses Dijkstra's algorithm to calculate the shortest path

• OSPF routers exchange link-state advertisements (LSAs) to build a topology map of the network

• It supports VLSM (Variable Length Subnet Masking) and CIDR (Classless Inter-Domain Routing)

• OSPF is widely used in large enterprise networks and ISPs

BGP parameter refers to the various attributes and settings used in the Border Gateway Protocol for routing decisions.

• BGP parameters include attributes like AS path, next hop, local preference, and MED.

• These parameters help BGP routers make decisions on the best path to reach a destination.

• Examples of BGP parameters are weight, local preference, and community values.

BGP (Border Gateway Protocol) is a standardized exterior gateway protocol used to exchange routing information between different autonomous systems on the internet.

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

• It is a path vector protocol that allows routers to share information about the best path to reach a certain destination.

• BGP operates on TCP port 179 and uses TCP connections to exchange routing information.

• BGP is commonly used b...read more

VLAN stands for Virtual Local Area Network, used to segment network traffic for security and performance purposes.

• VLANs divide a physical network into multiple logical networks, allowing for better control over traffic flow.

• Each VLAN operates as if it is its own separate network, even though devices may physically be connected to the same network switch.

• VLANs can improve network security by isolating sensitive data or systems from other parts of the network.

• VLANs can also imp...read more

A service route is the path that a service takes to reach its destination, including all the network devices it passes through.

• Service routes can include routers, switches, firewalls, and other network devices.

• Understanding service routes is important for network security to identify potential vulnerabilities or points of failure.

• Examples of service routes include the path an email takes from sender to recipient, or the path a website request takes from user to server.

OSPF (Open Shortest Path First) is a routing protocol that uses link-state routing algorithm to determine the best path for data packets.

• OSPF routers exchange link-state advertisements (LSAs) to build a topology map of the network.

• Each router calculates the shortest path to each network based on the information in the LSAs.

• OSPF uses cost as a metric to determine the best path, with lower cost paths being preferred.

• OSPF supports multiple areas to scale large networks and reduc...read more

The expected CTC for the Senior Network Security Engineer position is based on experience, skills, and industry standards.

• CTC expectations vary based on the company, location, and level of experience

• Candidates can research industry standards and average salaries for similar roles

• Negotiation skills can play a role in determining the final CTC offer

Firewall is a network security system that monitors and controls incoming and outgoing network traffic. NAT (Network Address Translation) is a process used to modify network address information in packet headers while in transit.

• Firewall acts as a barrier between a trusted internal network and untrusted external network

• Firewall can be hardware-based or software-based

• NAT allows multiple devices on a local network to share a single public IP address

• NAT can be used to hide the i...read more

Firewall architecture involves packet filtering, stateful inspection, and application layer filtering to protect networks.

• Firewall acts as a barrier between internal network and external network

• Packet filtering examines packets based on predefined rules to allow or block traffic

• Stateful inspection tracks the state of active connections to make decisions on allowing or blocking traffic

• Application layer filtering inspects data at the application layer to block malicious content...read more

Firewall traffic flow refers to the movement of data packets through the firewall based on defined rules and policies.

• Firewall inspects incoming and outgoing traffic to determine if it should be allowed or blocked

• Traffic flow can be controlled using access control lists (ACLs) and security policies

• Firewall can also perform Network Address Translation (NAT) to hide internal IP addresses

• Examples of traffic flow include allowing HTTP traffic on port 80 while blocking FTP traffic...read more

Fortigate IPsec tunnel is a secure connection established between two Fortigate devices for secure communication.

• IPsec tunnel is used to encrypt data traffic between two Fortigate devices

• Fortigate devices authenticate each other using pre-shared keys or certificates

• IPsec tunnel can be configured using the Fortigate web interface or CLI commands

Packet flow in Fortigate involves ingress, inspection, routing, and egress stages.

• Ingress stage: Packet enters the Fortigate device through a physical or virtual interface.

• Inspection stage: Packet is inspected by security policies, firewall rules, and security services like antivirus and IPS.

• Routing stage: Packet is routed based on destination IP address and routing table.

• Egress stage: Packet exits the Fortigate device through another interface towards its destination.

• Example...read more

U-turn NAT is a network configuration where traffic enters and exits the same interface on a network device.

• U-turn NAT is also known as hairpin NAT or NAT loopback.

• It allows internal hosts to access resources using their public IP address from within the same network.

• This is commonly used in scenarios where internal hosts need to access a server using its public IP address.

• U-turn NAT can be configured on firewalls or routers to allow for this type of traffic flow.

Wildfire is a type of malware analysis service provided by Palo Alto Networks.

• Malware analysis service

• Identifies and blocks unknown threats in real-time

• Utilizes machine learning and AI for threat detection

DC ACI stands for Data Center Application Centric Infrastructure, a software-defined networking solution for data centers.

• DC ACI is a technology developed by Cisco to automate network provisioning, management, and troubleshooting in data center environments.

• It uses a policy-driven approach to simplify network operations and improve agility.

• DC ACI allows for centralized control and visibility of network traffic, making it easier to implement security policies and ensure compli...read more