F5 Networks
3.9 of 5 125 reviews
www.f5.com Seattle, WA 1000 to 5000 Employees

F5 Networks Senior Software Engineer Interview Questions & Reviews

Updated Mar 11, 2014
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Interview Experience 

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No Offer

Negative Experience

Easy Interview

Senior Software Engineer Interview

Senior Software Engineer
Seattle, WA

I applied online and the process took 4 days - interviewed at F5 Networks in February 2014.

Interview Details – Applied online and got a phone call in a couple of days.

First phone interview was about resume, some technical questions and two coding questions followed by Q-A, lasted for about 90 minutes. The hiring manager was nice and easy to talk with. She explained me everything about the team. I told the manager that I had another offer in hand, so I would appreciate if you could expedite the process because the work sounded like it will match my background and experience. It looked like she did not bother about it because she just wanted to go with the standard procedure. So, next round was another phone screen (questions for interview at the end).

2nd round was supposed to be 45 minutes phone screen, but interviewer called in 15 minutes late and apologized but did not extend the interview by 15 minutes. Some OOP questions, basic understanding of algorithms and then a coding question (on collabedit). This is where I was surprised. I was given 15 minutes to solve and code the problem and I completed it in 10 minutes. The answer was perfect and the interviewer also confirmed that. But I was asked if I copied it from internet because the code was perfect and covered the corner cases too. Obviously, I did not copy, so I politely said no. I believe the interviewer also told that I will be recommended for on-site interviews.

Next day, I was told that I was rejected. Reason ??? they don't share. Losers! I am glad I won't be working for such a team.

Questions below (fairly easy):
1st phone interview: Given an array of integers, find the missing element in it. (there is only one missing element in the array).
1st phone interview: Given an array of integers, find the sub array with maximum sum.
2nd phone interview question: Find out if a binary tree (does not matter if its BST or not) is balanced or not. i.e. delta of left and right subtree should not be greater than 1.

Some OOP/c++ questions:
If you have an empty class like class Foo{} and you create an object of that class, what would sizeof(object) be ?
What is the difference between merge and quick sort? Complexities (best and worst case)? Explain worst case of quick sort? When would you use one over other?
What is auto_ptr (STL)? (I had c++ written on my resume, so that's the reason I was asked this question)? Can you create a vector of auto_ptrs? What kind of issues would you encounter while managing the vector of auto_ptrs?

Interview Question – nothing to be specific...all were easy, except the size of an empty object of a class. We usually don't do that, so I could only guess logically   View Answers (2)

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No Offer

Neutral Experience

Average Interview

Senior Software Engineer Interview

Senior Software Engineer
San Jose, CA

I applied online and the process took 1 week - interviewed at F5 Networks in November 2013.

Interview Details – Did a phone screening, and got invitation to onsite interview immediately. Onsite is 1:1 with recruiter (never did see him, but his assistant), and two engineers. Asking mostly networking protocol related questions, and big/little endian.

Interview Question – When you enter an URL on the browser how things are setup in the network?   Answer Question

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No Offer

Neutral Experience

Average Interview

Senior Software Engineer Interview

Senior Software Engineer
San Jose, CA

I applied online and the process took 1 week - interviewed at F5 Networks.

Interview Details – a phone interview followed by an onsite interview with programming test. The phone interview was easy. Every 1:1 interview is like going through the resume first, and then asking one white board programming question. The white board questions were easy, but I didn't prepare well. The hiring manager ask me some standard behavior questions.

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No Offer

Positive Experience

Average Interview

Senior Software Engineer Interview

Senior Software Engineer
Lowell, MA

I applied online and the process took 1+ week - interviewed at F5 Networks in August 2013.

Interview Details – Very sharp (smart) HR, brief phone interview.
Nice, swift hiring manager, half hour phone interview.
Third step, onsite with engineers, architect, upper managerial staff. Way nicer than what I expected reading glass door reviews of other sites. Tech eval was a smart instantiation, look at this code and tell me what you see wrong - plenty to spot that's wrong. Way less nerve-wracking than spontaneous whiteboarding a function that does X.

Interview Questions

  • Technical detail questions, from your resume, from 10 to 15 years ago, in more detail than conceptual.   Answer Question
  • This position is well below your experience level, why are you interested in it? (I can only gather a company is unaware when they have premium work environments/staff.)   Answer Question

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4 people found this helpful

No Offer

Neutral Experience

Difficult Interview

Senior Software Engineer Interview

Senior Software Engineer
Seattle, WA

I applied through a recruiter - interviewed at F5 Networks in July 2013.

Interview Details – Was contacted by one of their recruiters who is named after a famous martial arts actor. Dealing with this recruiter was not a positive experience overall, he seemed kind of shady. The company makes good quality products and the people I talked to other than the recruiter were nice and obviously very talented. However the culture was kind of corporate and stiff.

Interview Question – Questions during phone screen: find an element in a binary search tree iteratively and recursively, find the depth of a binary search tree. Explain congestion window and slowstart threshold in TCP. What are the fields in the TCP header? How can the MSS be set in TCP? Find all pairs of numbers that sum to Z in a sorted array. Written test on site: what are the keywords that can be used as modifiers to int in ANSI C. Write a function in C to parse first name and last name out of a string that contains both in quotes. Write a function to print the binary representation of a number, including negative numbers. In person interviews on site: Implement a base64 encoder, what do "extern", "volatile" and "static" mean? can a variable be declared both extern and static? explain how the mpeg2 transport stream works. Write a function to perform run length encoding. What is the difference between char* a = "alice"; and char b[] = "bob"; ? Implement a stack push function that takes a double pointer to a stack type and a void pointer. What are the important things to consider in web cache design? How does a heap based priority queue work and how can it be improved? Design a malloc and free implementation (no coding). At the end of the on-site the recruiter said he would contact me in a couple of days. A week went by and I never heard from him. He just left me hanging, it seemed like he was purposely avoiding me. I had to call him several times to finally get an answer ... he said it was a tough decision for them but I was not "a good fit", no offer.   Answer Question

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Accepted Offer

Positive Experience

Average Interview

Senior Software Engineer Interview

Senior Software Engineer
Lowell, MA

I applied through a recruiter and the process took a day - interviewed at F5 Networks in May 2010.

Interview Details – Lots of technical interviews (language, data structure, algorithm questions), including a high-level conceptual design interview for a similar kind of product.

Interview Question – For me, trying to remember OO terms that I understood the concepts of tripped me up a little.   Answer Question

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4 people found this helpful

No Offer

Negative Experience

Average Interview

Senior Software Engineer Interview

Senior Software Engineer

I applied online and the process took 1 week - interviewed at F5 Networks.

Interview Details – Applied online, got a response within 2 days which was quick. Passed the initial phone interview. Then scheduled pretty quick for an onsite interview. The interview was a whole-day event. It started with a coding test which was easy. They mainly look at C programming basics. After that I was interviewed by 6 engineers + 1 manager. Almost all of them came with a paper having 3-4 coding questions per interviewer. I found that odd given that I already had a coding test. Some of them did look at the resume, but it was mainly an interview to see how quickly you could code. Most interviewers did not give me to ask any questions which was very odd. Also I think they need to look at the candidate before firing 3-4 coding questions (string, bit manipulation, etc).
If the candidate is a junior engineer I can understand. But if the candidate is having 10+ years of experience, I expect a bit more design questions rather than how quickly you can crank some code on the whiteboard. Most of the interviewers ended up asking the same questions, which I politely pointed out.
I did very well in the interview, but for me I did not feel comfortable with the process and the people. All seemed to robotic and there was no "warmth" or "welcoming feel". Did not seem like a nice place to work.
Also did not receive any feedback after the interview.

Interview Question – Nothing too difficult. Coding questions were standard questions designed for people with <5 yrs experience. Not appropriate for senior candidates.   View Answer

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2 people found this helpful

No Offer

Neutral Experience

Average Interview

Senior Software Engineer Interview

Senior Software Engineer
Seattle, WA

I applied through a recruiter and the process took 1+ week - interviewed at F5 Networks in October 2012.

Interview Details – A F5 recruiter contacted me, an information session phone call, then a phone interview.

I provided two available time - no response until the morning of the second available time. After which F5 rescheduled twice, and changed interviewer. Phone call did not came in until I ping the recruiter 15 minutes later. A regular phone interview mostly knowledge with no coding - interviewer did not seem to have prepared - told me recruiter will contact me in 2-3 days. No message. Followed up after a week and no reply.

Interview Question – JIT compiler and how it was designed and implemented - I had different opinions with the interviewer on some aspects - he dictated he was right - I did not debate.   View Answer

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2 people found this helpful

Accepted Offer

Positive Experience

Average Interview

Senior Software Engineer Interview

Senior Software Engineer
San Jose, CA

I applied through a recruiter and the process took 2 days - interviewed at F5 Networks.

Interview Details – Classic tech interview that lasts the entire day. You will be expected to know it all, but will not be discounted if you cannot remember it everything. With that said, most groups are most interested to see how you will get along culturally.

Negotiation Details – I was prepared to counter whatever they offered, but their offer was so good, I just accepted.

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No Offer

Neutral Experience

Difficult Interview

Senior Software Engineer Interview

Anonymous Interview Candidate
San Jose, CA

I applied online and the process took 2 days - interviewed at F5 Networks in April 2012.

Interview Details – I had a phone interview with the hiring manager. He was pleasant and introduced about the position and went over the resume. He asked lot of questions on Javascript
1. What is prototype inheritance? when would you use it?
2. What are closures?

I got selected for on-site. This is where i was not impressed by the team and the vibe in the company. The cubes in the company looked old and atmosphere did not sound vibrant.

I would have refused the offer even if i got the position.

Interview Questions

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