F5 ASM is a web application firewall that helps protect websites and web applications from attacks. When interviewing for a position that involves F5 ASM, you can expect to be asked questions about your experience and knowledge of the product. Answering these questions confidently can help you land the job. In this article, we review some of the most common F5 ASM interview questions.
F5 Interview Questions Part 01
Interviews for Top Jobs at F5
Software Engineer III Interview
I applied through a recruiter. The process took 3 days. I interviewed at F5 in Aug 2022
Interview
I got the job vacancy email from companies HR itself that your profile is matching and apply for a specific position on the f5 career portal. When I have applied, HR called me and told that, you are not eligible for role as recruiting manager knows you very well and he is saying you are not developer but the tester.To my surprise, I asked his name, after knowing his name I understood he was the same guy who was sacked from my current organization due to a performance issue and he just held a grudge on me. I have explained to HR that my total experience is of development only, and she must have shortlisted my profile by looking at my resume. Later she said that she will get back to this after discussing with him again, but within half an hour I got an email from f5 career page that my candidature was rejected. I didn’t even get a chance to appear for an interview just because of the recruiting manager’s behavior. Very bad culture for organizations like f5.
- Not got opportunity to appear for interview even after 95% of the skills are matching.
Technical Writer II Interview
The process took 6 weeks. I interviewed at F5
Interview
A couple weeks after applying, I got an email from the recruiter saying that the hiring manager wanted to speak with me and he asked me for availability to set up an interview. I responded back that day and never heard back. Weeks later, I received the same email from the same recruiter asking for interview availability, as if he had never talked to me before. He also left a voicemail. Again, I responded to the email immediately. After a few days of not hearing back, I gave him a call and he said he was behind on emails, which is why he hadn’t responded. He seemed excited to talk to me and told me he was going to pass on my updated availability to two hiring managers. I never heard back, and weeks later, I got an automated rejection email from the company. It’s possible that there was more going on behind the scenes, but the hiring managers clearly wanted to talk to me and I feel robbed of an opportunity to interview for this company due to poor communication. The whole ordeal spanned about 6 weeks.
- I never made it to the interview
Top F5 Load Balancer Interview Questions and Answers
Server Load Balancing (SLB) optimizes network speed and content delivery by utilizing a variety of techniques and prioritization to react to network requests. SLB allocates users to a set of servers and guarantees that users are not routed to failing servers.
SLB utilizes two distinct forms of load balancing:
To begin, load balancers are classified as software-based and hardware-based. Vendors of hardware such as F5 Networks and Citrix include the software-based load balancer within their products.
You’ll need the cookie’s name and value, the VIP to which you’re binding, and the groupings to which you’re balancing.
The load balancer’s Health Check function enables you to configure settings for doing diagnostics on the functionality of web servers connected with each appliance. Health checking enables you to ascertain whether a server or resource is operational or has failed.
The three advantages of utilizing SLB are as follows:
iControl is a web service-enabled Application Programming Interface that provides granular control over F5’s application administration and customization platform.
Global Server Load Balancing is quite similar to SBL, except that it enables us to load balance VIPs from many geographical locations as a single entity. Additionally, GSBL enables geographic site expansion and low latency.
The easiest method of enabling GSLB is through the use of CDN (Content Delivery Network). Global CDN will collect data from their clients’ origin servers, cache it on geographically distributed servers, and offer dependable internet content to consumers worldwide.
Typically, persistent cookies are retained on the user’s device. These cookies enable us to remember our users’ credentials, as well as information, preferences, and settings. Essentially, these cookies are used to enhance the user’s online experience.
The Persistent Cookie strategy assigns a cookie to a group depending on its name. A QoS Cookie policy determines the server group to which a cookie is assigned depending on the identity and value of the cookie issued to that unit.
This is determined by the load balancing strategy you choose. Following are a few examples:
Reverse Proxy Cache is a caching that resides next to the source server, as the name implies. When a user requests a cached item, the proxy will respond from the cache rather than the origin server.
Yes, the clustering must be enabled in order to leverage GSLB. Each proxy in the network should have a configuration that is similar. As a result, if an appliance becomes a zone master, it may act as a DNS.
When there are more queries than the server can handle, this is referred to as Overflow. Overflow is one of the techniques in array GSBL that addresses this issue by redirecting queries to another server when the local site reaches 80% of its capacity.
The “least connections” approach directs clients to sites with the fewest contemporary links.
Round-robin is one of the most straightforward ways for spreading client requests over a set of servers. As each query is sent to one of the group’s servers, this protocol instructs the load balancer to continue the procedure until no more queries are received.
Various load balancing strategies include the following:
A pool is a collection of equipment, such as web servers, that work together to collect and handle the traffic. BIG-IP does not route client information to the specified destination IP address in the user requests. Rather than that, it transmits the request to the subscribers of that group.
The load balancer’s nodes will assist you in routing customer queries to the specified destination. In basic terms, the node serves as a conduit for the client’s request to reach its destination.
Question 1: What do you mean by load balancing pool?
Answer: A load balancing pool contains a group of devices such as App/Database servers to receive and process the traffic. The client sends the request to the VIP, which is set up and configured on BIG-IP LTM, then distributes/forward the traffic to any member who is part of the load balancing pool. This way, traffic is distributed efficiently among pool members and helps in saving the server resources.
F5 LTM Interview Questions and Answers
An iRule is a powerful and adaptable feature with BIG-IP Local Traffic Manager. It can be used to manage your network traffic.
Using syntax, the iRules feature does not only let you select pools based on header data but it allows you to direct traffic. It does so by searching for any type of defined content data.
Therefore, iRules allows you to customize your content according to your own needs.
In other words, iRules lets you specify the direction of your traffic to a particular destination.
With the help of iRules, you can send your traffic to the following:
if {[IP::addr [IP::client_addr] equals 10.10.10.10]} {
The iRule is activated when a client-side connection is accepted. It then lets the Local Traffic Manager to send the packet to the pool my_pool , if the client’s address matches 10.10.10.10.
FAQ
What is F5 load balancer interview questions?
- Question 1: What do you mean by load balancing pool? …
- Question 2: What is the default MGMT port IP Address for F5 BIGIP LTM? …
- Question 3: What is iRule in F5 BIGIP LTM? …
- Question 4 – What is iControl? …
- Question 5 – What is OneConnect? …
- Question 6: What is a profile in BIGIP LTM?
What is F5 Networks used for?
What are F5 products?
- BIG-IP and BIG-IQ VE. …
- Silverline WAF. …
- Silverline Shape Defense. …
- F5 NGINX Plus with F5 NGINX App Protect. …
- F5 NGINX Ingress Controller with F5 NGINX App Protect. …
- F5 NGINX Management Suite.
