Cisco Interview Questions

About Cisco

Cisco Systems, Inc., is a multinational digital communications technology conglomerate headquartered in San Jose, California. Cisco designs, manufactures, and sells networking hardware, software, telecommunications equipment, and other high-tech services and products. Cisco focuses on specific technology markets such as the Internet of Things (IoT), domain security, videoconferencing, and energy management, with leading products such as Webex, OpenDNS, Jabber, Duo Security, and Jasper. Cisco is one of the world’s largest technology companies.

Cisco Interview Process

face the Cisco interview rounds to demonstrate their competitive abilities for a variety of technical positions.

Three rounds make up the Cisco interview process:

• Aptitude round
• Technical Interview round
• HR interview round

Aptitude Test: Among other things, topics like probability, permutations and combinations, profit and loss, algebra, simple and compound interest, and number series are essential for cisco coding questions about them in the Cisco interview process.

Here the interview questions will majorly ask in the interviews. Overall, you are required to prepared well before the interview rounds of Cisco. We covered the almost 7 topics in Cisco interview questions, like:

• Cisco Aptitude Questions
• Cisco Interview Questions
• Cisco ASA Interview Questions
• Cisco ACI Interview Questions
• Cisco ISE Interview Questions
• Cisco Nexus Interview Questions
• Cisco HR Interview Questions

Top Cisco Interview Questions and Answers

1. What exactly is a diskless workstation?

Client computers that are connected to a networked server are known as diskless workstations. The user can interact with the system with the bare minimum of hardware. They don’t have a hard drive, so data and programs used for data storage, booting up, and performing calculations are retrieved from the network. Because all files are in one location, diskless workstations simplify security and backups while also lowering overall LAN costs.

2. Why do we route?

Routing is the process of choosing the paths that data packets will take to get to a specific location. A router is used to choose a path for traffic within or between networks. To relay data, a hardware configuration is necessary.

3. What kinds of memories are there in a Cisco router?

A Cisco router has the following three different types of memories:

• NVRAM for the startup configuration file storage.
• DRAM for keeping track of the configuration file’s execution.
• Cisco IOS is kept in flash memory.

4. How does recovery testing work?

The ability of a piece of software to bounce back from setbacks—such as network outages, software/hardware crashes, etc. is determined by a software testing technique. In order to confirm that the recovery is carried out correctly, it involves several forms of forced software loss.

5. Which protocol will be implemented for diskless workstation bootup?

The diskless workstations will be booted independently over the Internet using BootP, also known as the Bootstrap Protocol. BootP will enable a computer to obtain both their own IP address and the IP address of the server, much like DHCP (Dynamic Host Configuration Protocol) does.

Cisco ASA Interview Questions

1. What are the different levels of ASA security?

In ASA, security levels are nothing more than firewall interfaces. The ASA firewall has security levels ranging from 0 to 100. The fact that the security level inside is 100 indicates that it is more trustworthy. The fact that the security level on the outside interface is 0 indicates that we cannot trust it because it is in the untrusted mode.

2. Describe transparent Firewall. Likewise, define how it works.

Transparent firewalls are capable of serving as a layer 2 device. Transparent firewalls are simple to set up on existing networks. We can easily pass from higher security levels to lower security levels in transparent firewall layer 3 traffic without any access-list configuration.

3. How a firewall uses stateful inspection?

State tables or connection tables are present in stateful firewalls. We can monitor all connections that are active using in-state tables. Stateful firewalls have dynamic state tables that can change based on each connection’s current state. The state table is examined by Stateful Firewall first, followed by the policies.

4. What kind of data is kept by the firewall for Stateful Inspection?

The following kinds of data are kept by stateful tables:

• Source Ip address
• Destination Ip address
• IP protocol TCP & UDP

The only TCP/UDP port numbers, TCP sequence number, and TCP flags that are available for us to use as IP protocol information are

5. How does the packet flow in ASA work?

• The state table entry that already exists will be checked when we receive a packet at the ingress interface. If they do, that packet will be subject to a protocol inspection.
• If the packets are different, they are either TCP-SYN or UDP packets. The packet will then be sent for an ACL check.
• If the packet is permitted by the ACL, the translation rule will verify it before the protocol inspection is performed on the packet.
• The egress interface translates the IP header using the NAT translation rule.
• The packet will perform a route lookup after passing through the egress interface.
• The packet will perform a route lookup after passing through the egress interface.

6. Which features does Transparent Firewall not support?

• Multicast
• Dynamic Routing
• QOS (Quality of Service)
• VPN (IPsec and webVPN connections cannot be ended)
• Unable to serve as DHCP relay agent

7. Is it possible to block HTTPS traffic on a firewall?

The ASA does not support filtering of HTTPS traffic. Due to the fact that HTTPS traffic only carries protected content, ASA cannot perform deep packet inspection or inspection using regular expressions (SSL).

8. What differentiates a Stateful Firewall from a Stateless Firewall?

Stateful Firewall is the response. Stateful Firewalls are equipped to track and identify the status of all network traffic. A Stateful firewall is aware of connections that pass through it, and they can track and defend based on traffic flow patterns.

It updates and maintains information in a state table, also known as the connection table, about user connections. It then establishes security rules that apply to user connections using this connection table. Stateful firewalls include those made by Juniper, ASA, and Checkpoint.

Stateless Firewalls: Stateless firewalls focus on particular packets and employ pre-defined rules to filter traffic. However, stateless firewalls only look at the packets and don’t check the connections’ status. The Extended Access Control lists available on Cisco’s IOS Router are a great illustration of a filtering firewall.

9. How can I set up a static route on ASA?

# route outside of Destination IP> Subnet Mask> Next Hop>

10. What command should I use to view NAT Translations?

# show xlate

# show nat

Cisco ACI Interview Questions

1. What operating modes do switches in the Nexus 9000 series have?

Nexus 9K Switches can be used in NX-OS and ACI Mode, respectively. These modes are mutually exclusive, so a switch cannot operate in both modes at once. If you change the mode, the entire configuration will be lost.

2. What does the ACI APIC controller do?

APIC stands for Cisco Application Policy Infrastructure Controller. Cisco APIC is the main structural component of the Cisco ACI solution. It acts as a single point of automation and management for the Cisco ACI fabric, policy enforcement, and health monitoring in both physical and virtual environments.

In addition to enhancing performance, the controller manages and runs a scalable multitenant Cisco ACI fabric. The only point of control for ACI Fabric is the APIC controller. We also have the option of logging into particular switches for the purposes of troubleshooting and verification.

3. What occurs if every APIC controller in the fabric fails?

There won’t be any interruption in traffic forwarding even if all APIC controllers fail. To create new policies or to monitor and troubleshoot the ACI fabric, we must bring up the APIC controller because we are unable to make any changes to the fabric.

4. In ACI Spine-Leaf Architecture, how do we connect servers?

There will be no connections to any other devices other than Leaf Switches, including the APIC controller. You can create a vPC (Virtual Port Channel) at leaf switches if one server is connected to two leaf switches. Since the Cisco architecture forbids link connections between leaf and leaf switches, we do not currently have any vPC Peer links between Leaf Switches.

5. What exactly is Endpoint, End Point Group (EPG)?

Endpoints are objects that are directly or indirectly linked to the network. They can be virtual or physical and have an address, a location, attributes (like the version or patch level), and examples include bare-metal servers, switches, routers, firewalls, IDS, and IPS.

Endpoint groups, or EPGs for short, are groups of endpoints that stand in for particular applications or parts of applications. EPGs, like EPG-web, EPG-DB, and EPG-App, are objects that represent a collection of endpoints that have certain things in common.

Cisco ISE Interview Questions

1. What is ISE (Identity Services Engine) from Cisco?

To put it simply, you have control over who has access to your network and when and what they can access. It scales to millions of endpoints and can authenticate users over wired, wireless, and VPN connections.

For endpoint devices connected to the company’s network administrator devices, such as routers and switches, Cisco Identity Services Engine (ISE), a product for network administration, enables the creation and enforcement of security and access policies. The goal is to make managing identities across various devices and applications simpler.

2. What kinds of personas does Cisco ISE support?

Monitoring Node (MnT), Policy Services Node, and Policy Administration Node (PSN).

All three personas can run on the same device or distributed across several devices for redundancy, depending on the size of your deployment.

3. How can ISE be deployed?

Endpoint devices connected to a company’s network can have access policies created and enforced using ISE, which can be installed either on a physical appliance or a virtual machine.

Physical appliances include the SNS 3400(EOL), SNS 3500, and SNS 3600. Installing ISE on VMware and Hyper-V

4. What is Cisco ISE’s primary goal?

The user is validated against the server each time a wired or wireless user attempts to access the network or a device [for device administration] to see if they are authorised to do so. The user’s access to the network or device will vary depending on the outcome.

5. What distinguishes the Cisco ISE and ACS systems?

ACS is used to verify user identities for VPN connections and network devices, but it is not a NAC solution because it cannot manage the network by determining whether or not its devices are compliant.

The network authentication technology known as ISE is much more advanced than ACS. ISE is required to implement complete network access control.

6. What are all the different licences that are available on ISE?

• ISE Base only
• ISE Base and Plus
• ISE Base and Apex
• Device Administration
• ISE Base, Plus, and Apex

7. What does Cisco ISE’s Identity Store do?

We use Identity Store to check the credentials against a specific database. Internal or external identity store databases are both possible. The term “internal identity store” refers to locally created Identity/Endpoint data on ISE. AD, LDAP, Radius token server, RSA, and Certificate Authorities are examples of external identity stores.

8. What are the various protocol types that the ISE supports?

For authenticating and authorizing end clients, various protocols are available on ISE. Here are a few well-known and frequently used protocols.

EAP-TLS, PEAP, MS-CHAPv2 v1 and 2, EAP-TTLS, EAP-MS-CHAPv2, LEAP, and EAP FAST.

9. What RFC Standards are there in Cisco ISE?

According to the following RFC Standards, Cisco ISE:

RFC 2138: Remote Authentication Dial in User Service (RADIUS)

RFC 2139: RADIUS Accounting

RFC 2865: Remote Authentication Dial in User Service (RADIUS)

RFC 2866: RADIUS Accounting

RFC 2867: RADIUS Accounting Modifications for Tunnel Protocol Support

RFC 5176: Dynamic Authorization Extensions to Remote Authentication Dial in User Service (RADIUS)

10. What are the essential elements of MAB and dot1x authentication?

The three main elements in dot1x authentication are the Authentication Server, Network Access Device, and Supplicant.

Supplicant: The user or endpoint attempting to log in so they can access the network.

NAD: Access switch or access point to which the supplicant is connected. The user’s credentials will be carried by the NAD and presented to the server for user authentication.

Server for authentication: NAD-provided credentials will be checked on the server, and depending on the outcome, access will either be granted or denied.

Cisco Nexus Interview Questions

1. Is Nexus a router or switch?

The Nexus 7000 is the true modular switch in the Nexus family, with six versions that include a 4 slot, a 9 slot, two 10 slot, and two 18 slot switch. The Nexus 5000 had some modular capabilities, and you could attach the Nexus 2000 fabric extender to the 5500 range.

2. Why we use Nexus switch in data center?

The Cisco Nexus core switching system is sweeping the datacenter, and there are compelling reasons why IT professionals are incorporating it into their server and storage systems. The move to densely virtualized servers with quick access to shared storage has occurred at the same time that 10G Ethernet ports are widely available on servers. To connect all of these 10G Ethernet ports, a high-speed switching fabric is required.

This switched network’s dependability, speed, and flexibility are all enhanced by the Nexus switches in three key ways:

• Fabric Extenders.
• Virtual Port Channe
• Unified Fabric.

3. What exactly is Cisco DCNM?

Cisco DCNM is an abbreviation for Data Center Network Manager. It is a centralized management console for data-center fabrics built on Cisco Nexus switches, MDS, and Cisco UCS. By providing effective operations, monitoring, and infrastructure troubleshooting for the Data Center network, DCNM’s primary goal is to reduce operational costs. It offers a graphical user interface for managing switches and viewing them, along with a RESTful API that enables automation.

4. What is Cisco Nexus FCoE?

Fiber Channel over Ethernet is known as FCoE. This technology makes unified I/O on servers possible. When a network adapter has unified I/O, it can handle both LAN and storage data traffic.

5. Describe Fabric Path.

STP (Spanning Tree Protocols) and vPC are in some ways replaced by the Cisco proprietary switching protocol known as fabric path (Cisco virtual port-channel). Layer 2 and Layer 3 functions are combined by Fabric Path, giving Layer 2 the simplicity and Layer 3 the intelligence.

Cisco HR Interview Questions

• Why did you decide to join Cisco for this position?
• What are your pros and cons?
• What has been your journey’s biggest networking obstacle so far?
• Why are you qualified to be a network engineer?
• Have you ever worked as a network engineer before?
• What method do you use to assign tasks a priority?
• Why do you plan to leave your current position?
• Is there a particular reason you’re leaving your current job?
• What do you hope to accomplish in the next ten years?

Conclusion

This top Cisco interview questions and answers guide will help you confidently face the questions at your upcoming Cisco interview. Cisco interview questions have been covered for both freshers and experienced professionals. This blog also discusses technical and cisco networking interview questions and answers. You can boost the weight of your resume by pursuing a Cisco certification or course.