Firewall discussion

Why are firewalls so important within an IT environment? What are the different firewalls and are all types still in use today? What concepts/inputs would you consider when updating an out of date firewall within an IT environment?

Your initial post should be 250-300 words. There must be at least two APA formatted reference (and APA in-text citation) to support your thoughts in the post. Do not use direct quotes, rather rephrase the author's words and continue to use in-text citations.