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Let's say I work for a big enterprise organization. When looking at my IP address, I notice that it is not a private IP address but is instead a public IP address.

What are the benefits of organizations issuing public IP addresses instead of NAT'ing private IP addresses?

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    NAPT breaks protocols other than TCP, UDP, and ICMP, and it even breaks some applications and application-layer protocols the use TCP and UDP. – Ron Maupin Sep 15 at 20:09
  • @RonMaupin I would assume TCP and UDP make up the majority of enterprise software so I can't imagine NAT limiting much if anything. – Izzo Sep 15 at 20:12
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    Businesses use things like routing protocols, VoIP, video, etc. that are hurt by NAPT and require ugly workarounds. NAPT is a kludge to get around the IPv4 address shortage until IPv6 is ubiquitous, and it often requires even uglier kludges to get around what it breaks. See the section about NAT/NAPT in this answer. – Ron Maupin Sep 15 at 20:15
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NAT is a workaround or "hack" for coping with the lack of IPv4 address space. Using (the same) private IP addresses in private LAN has tremendously extended the life of IPv4 - yet, NAT breaks TCP/IP's original end-to-end paradigm. NAT even breaks quite a few protocols which often have their own fixes and workarounds for that.

So, NAT should generally be avoided wherever possible. If your company is fortunate enough to own a large enough pool of public addresses it's a good choice to not use NAT.

IPv6 which its huge address space is designed to remove all need for address translations. Even though v6 has its own schemes for private addresses (link-local and site-local), these addresses are never translated as each node can also have a public address.

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