I applied through university. The process took 4 weeks. I interviewed at Sourcefire (Columbia, MD) in May 2015
Interview
I took take-home test first which is basically c programming problems and network related conceptions. Then I went to Columbia for onsite. There were 4 rounds. They recommended to use C in interview but not required. The problems were not hard but they might comp up with some follow-ups regarding OS or network.
Interview questions [1]
Question 1
Reverse a string, find IP address, reverse linked list etc
The entire process was unorganized and a few people did not show. The interviewers used every curse word imaginable. They used disguised insults, as well. They totally wasted my time. They spoke highly of their reputation because they are now a part of Cisco. However, this is the way that they conduct business.
Interview questions [1]
Question 1
Brush up on IP Fragmentation and IDS Evasion techniques.
I applied in-person. The process took 5 days. I interviewed at Sourcefire (Columbia, MD) in Jan 2012
Interview
6 engineers from different teams UI/Database/snort/networking/support/maintenance asked to write code, asked language and data structure questions. Asked general networking questions, knowledge of protocols. Schedule preference, desired level of involvement in customer issues.