Hello I went to a job interview in which the knowledge on linux security had to be vast. However, I was not disclosed detailed information on the solution in place, however I was told that Linux was used as the front line of defense and had a firewall installed on it which is open source according to the manager. I was wondering if you experts were familiar on those types of open source programs/solutions for linux.
I was also wondering where does that leave CISCO firewalls compared to the linux-only solution. In addition, the interviewer also told me that he taught CISCO in a technical shool for many years and that has left me wondering since he told me that there are Linux Security certifications that cost more than $3,000 US and that very very few people had those certs since they were so hard and costly.
Can somebody please enlighten me on this secret world of Linux Security. Thanks.