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NAT stands for Network Address Translation, which means a NAT device maintains a translation table of internal IPs to external, so that it can return response p
by slt2021 3y ago
NAT stands for Network Address Translation, which means a NAT device maintains a translation table of internal IPs to external, so that it can return response packets coming from Internet to a proper destination on the internal network.
By definition NAT will maintain state which is translation table. Now that table can be dynamic or static, but it doesn't change the fact that there will be some state to maintain.
- sgjohnson 3y ago> By definition NAT will maintain state which is translation table. Stateless NAT is also possible, but then it has to be 1:1. Which has it's purpose, but is rarely used. A practical example would be with IPv6 if your ISP doesn't allocate you a static prefix. Stateless NAT would allow you to use a /64 from the private range of fd00::/8 in your local network which the router would translate to your globally unique /64. No state needed, because there would be as many IPs available in your LAN prefix as in your GUA prefix. All it would do would be translating fdxx:xxxx:xxxx:xxxx:1234:1234:1234:1234 to 2yyy:yyyy:yyyy:yyyy:1234:1234:1234:1234 and vice versa. I've also done stateless NAT on IPv4. When you request more IPs from some cloud providers, they assign you a bunch of /32s, not a proper subnet, virtually requiring you to run a cloud router.