How to host my own external DNS serer?

You could use Microsoft Azure's DNS service which is easy to use.

Azure DNS documentation | Microsoft Learn

If you have a permanent IP address from your ISP it's relatively easy to set up MS or Linux DNS, problem can be PTR records since your ISP may not want to delegate a fraction of a net block to your DNS server (assuming you get about 8 IP addresses from them rather than a whole block.

I should have been more clear, I aplogize.  With all the censoring taking place, we're a bit worried that at anytime, big brother, or tech companies if they want to censor us, they can take us offline just by contacting our external DNS organization and disable or delete us.

So I would like to run my own Winwos/Linux server internally, inside my organization, and not in the clund (azure or aws), as that can be shutdown as well.  I understand that even our own ISP technically can shut us down, but at least I can take that server and move it to another ISP and bring it back up.

I forgot to mention, I have a /26 block of public IPs.

You have to instruct your domain registrar to set the NS record for your domain to be one of your public IPs and set the firewall to forward DNS queries on that IP to your server, then any query of WWW or MX or whatever will go to that address. You're still at the mercy of the registrar of course at least for .com addresses. .co.uk you can get your own tag that lets you be your own mini-registrar but then you're at the mercy of the UK NIC.

So how do I become my own external DNS registrar?

True, our own ISP can drop us as well.

What TLD are you using?

You can't be your own registrar unless you buy the custom tld (Its only  185,000)  https://www.templetons.com/brad/dns/vanity-tld.html

Do you really own a /26 and have an AS Number? Or are you leasing one?

Becoming a registrar is free for .co.uk but each domain registered costs the full £80 unless you pay to become a member of Nominet. There are several self-managed registrars so Brighton & Hove City Council rub shoulders with Go Daddy in the list of UK registrars although Brighton Council are a self-registrar and won't register domains for customers. You're then at the mercy of Nominet of course but at least they are a not-for-profit company rather than a big business.

I have no idea how you become a .com registrar.

I reside in the USA, so I guess it would be different for me.  I would need to register .com, .org  domains, perhaps a few others.

@David

So we are the owner of our own TLD, I think we pay a yearly price to renew it, but it's regular .com  or .org domain, which only costs a few hundred or something per year.

I have a public, static block of /26 IPs for my organization, about 64 IPs or so, they are assigned from my ISP.  Not sure if they charge us extra or not.  I'm not sure what you mean by an AS number?

I guess I don't own them, but they are assigned to use my our ISP, so if we are no longer a customer of their, they will assign those IPs to someone else, so I guess I don't own them :)

So are you saying if I buy my example.com domain, then no one can shut us down, not even the government?

What if my example.com domain is with godaddy.com, can godaddy shut us down even if I own our domain, example.com?

Initial Answer: Yes. We've done it for years.

Question: What product do you have in mind to host the DNS?

I'm confused, from NOCI's response, seems like it's not worth running my own DNS for external requests, as even if we do that, the government can still shut us down.

Then Philip, you mention you've done it for years, but does that mean that if big tech or government wants to shut me down, that it can't if I run my own DNS for external DNS requests?

I understand we're at the mercy of our ISP anyways, as they can shut us down as well.

I see,  so I don't have control over the NS record and A records?  I mean I do now, but I get it, so does the Gov as well.

Thanks for the info.

The NS and corresponding A records aren't stored/served by the registrar Philip, they're served by a.gtld-servers.net, b.gtld-servers.net etc. The protocols used by registrars to create and update those records on the TLD and ccTLD servers aren't normal DNS protocols, in my day we sent a fax to the UK NIC!