Daniel sent us this one — he's asking about DNS fundamentals, the kind of thing you learn once and then never really revisit. He points out that the record types, A records, CNAMEs, TXT records, have been remarkably stable for decades. But then he asks the deeper question: what does a CNAME actually mean, as opposed to an A record? Why can you sometimes accomplish the same thing with different record types? And then the practical piece — the trend has moved against "www" in URLs, it sounds almost like dial-up now, but you still often need a CNAME to redirect to the apex domain. Is that still best practice? He wants us to walk through the basics for people using services like Cloudflare, handling encryption settings to the endpoint, that whole stack.
Oh, this is a beautiful question. DNS is one of those things where the surface is deceptively simple and then you fall through a trapdoor into decades of accumulated weirdness. And the CNAME versus A record thing is the perfect entry point because it looks like a trivial implementation detail and it's actually a design constraint that shaped how the entire web is addressed.
I love that you just called DNS record types "beautiful." This is why people listen.
They listen for the passion, Corn. They listen for the unvarnished enthusiasm of a retired pediatrician explaining canonical name resolution.
A man who has clearly never been to a party.
I've been to parties. I just choose to leave early and read RFCs.
Walk me through it. What is a CNAME actually doing that an A record isn't?
An A record maps a domain name directly to an IP address. You type "example dot com," the A record says "that's at one ninety-two dot zero dot two dot one." It's a direct pointer. One name, one IPv4 address.
Name to number.
A CNAME doesn't point to an IP address at all. It points to another domain name. It says, "whatever you're looking for here, go ask that other name instead." So if you create a CNAME for "www dot example dot com" pointing to "example dot com," the resolver says, "oh, I need to go resolve example dot com first, and whatever IP that gives me, that's your answer.
It's a redirect at the DNS level. The user's browser never sees the CNAME resolution happening.
The resolver follows the chain transparently and returns the final IP. The browser just gets an IP address and connects. And this is where the design constraint kicks in — the one that's been causing headaches since the late nineties. RFC 1912, the DNS operational guidebook, says a CNAME cannot coexist with any other resource records at the same name.
Wait, say that again. A CNAME at a given name means you can't have anything else at that name?
No A record, no MX record for mail, no TXT record, no NS records. The CNAME owns that node exclusively. The logic is straightforward — if you have a CNAME saying "this name is just an alias for that other name," then asking "but what's the MX record for this name" creates an ambiguity. Do you want the MX record from the alias, or from the target? The standard says: don't create the ambiguity. CNAME means everything follows the target.
Which means at the apex domain — the bare "example dot com" — you can't use a CNAME.
Because the apex domain already has other records. It has to have NS records pointing to your nameservers. It almost certainly has an SOA record, the Start of Authority, which is the metadata record that says who manages the zone and how often to refresh. Those records exist at the apex whether you want them there or not. So a CNAME at the apex violates the spec.
This is the entire reason "www dot example dot com" exists as a convention.
This is it. People think the "www" subdomain was some kind of semantic choice, like "we're labeling this as the world wide web service.It was a technical workaround. In the early days, you'd have a server that handled multiple services — maybe the same machine did web, FTP, and email. You'd use different subdomains: www for web, ftp for file transfer, mail for email. But as the web became dominant, people wanted to just type "example dot com" into their browser. The problem was, if your web server was hosted on some other infrastructure — a CDN, a cloud provider — you needed to point your domain to their infrastructure. And the flexible way to do that is with a CNAME.
Because an A record ties you to a specific IP, and if the provider changes their IP addresses, your A record goes stale.
If you're using Cloudflare's CDN, or AWS CloudFront, or any service where the provider manages a pool of IP addresses that can change without warning, you want to point to their hostname, not hardcode an IP. A CNAME lets you point "www dot example dot com" to "example dot cloudflare dot net" and Cloudflare can change their backend IPs all day long and you never have to touch your DNS.
At the apex, you're stuck with an A record.
You're stuck. And for years, the standard advice was: set up an A record at the apex pointing to your web server's IP, and a CNAME for "www" pointing to the apex or directly to your hosting provider. Then configure your web server to redirect anyone who types "example dot com" to "www dot example dot com," or vice versa. Pick a canonical domain and enforce it.
That's where the "www" started to feel like dial-up. It became this visible artifact of a technical constraint that nobody wanted to explain.
Marketing teams hate "www." It adds four characters, it looks cluttered on business cards, it feels dated. So the trend has been toward using the bare domain as the primary web address. But that brings us right back to the CNAME-at-apex problem.
Because clearly something changed, or we'd all still be typing "www.
Two things changed. The first was that some DNS providers started implementing what's called "CNAME flattening" or "ALIAS records." Cloudflare calls it CNAME flattening. DNS Made Easy calls it an ANAME record. Route 53 in AWS calls it an Alias record. They're all slightly different implementations of the same idea.
The provider does the CNAME resolution for you, on their side, and serves the resulting IP address as if it were an A record. So you configure what looks like a CNAME at the apex — you point "example dot com" to "example dot cloudflare dot net" — but behind the scenes, Cloudflare's authoritative nameservers resolve that target hostname, grab the current IP addresses, and respond to DNS queries with those IPs in A record format. The resolver on the querying side never sees a CNAME. It just gets A records.
It's a sleight of hand. The DNS protocol itself hasn't changed. The provider is just doing the resolution step internally and lying to the outside world about what kind of record it is.
That's exactly what it is. It's a beautiful hack. Cloudflare introduced CNAME flattening to solve precisely this problem. And it's transparent to every resolver on the internet — they get standard A record responses, fully compliant with the protocol, no RFC violations. The flattening happens entirely within Cloudflare's infrastructure.
This is why services like Cloudflare can offer what looks like a CNAME at the apex, while technically staying within the rules.
And the second thing that changed is the rise of anycast networks and stable IP infrastructure. If you're using Cloudflare for DNS and proxying, your apex A records point to Cloudflare's anycast IP addresses, which are effectively stable. You're not pointing to your origin server's IP directly — you're pointing to Cloudflare's edge, and Cloudflare handles routing to your origin. So even with traditional A records at the apex, you're not as brittle as you'd be pointing directly to a single server in a rack somewhere.
The modern best practice for someone using Cloudflare — which is what the prompt is asking about — what is it? Apex with flattened CNAME? Or still a CNAME at www?
The modern best practice, straight from Cloudflare's own documentation, is to use CNAME flattening at the apex if your web property lives entirely at the bare domain. You create what Cloudflare calls a "CNAME record" at the root — their UI allows it — and their system flattens it automatically. You point the apex to whatever target hostname your hosting provider gave you. Meanwhile, you set up a "www" CNAME that also points to the same target, or to the apex. And then you configure Cloudflare's redirect rules to enforce one canonical domain — usually the bare domain now — and redirect the other to it with a 301.
The "www" CNAME still exists, it's just not the primary thing users see. It's there to catch anyone who types it.
You want both to resolve. You don't want to be the person who loses traffic because someone typed "www" out of muscle memory and got an NXDOMAIN. But the user-facing canonical URL is the bare domain.
Let's back up to something the prompt asked about — this idea that sometimes you can achieve the same thing with different record types. What's an example where an A record and a CNAME are functionally interchangeable?
The simplest case: you have a subdomain for a blog, "blog dot example dot com," hosted on some platform. If the platform gives you an IP address, you could create an A record pointing "blog" to that IP. Or, if they give you a hostname — "example dot hostingplatform dot com" — you could create a CNAME pointing "blog" to that hostname. Both get users to the same server. The difference is what happens when the platform changes its infrastructure.
With the A record, you wake up one morning and your blog is down and you didn't change anything.
You're scrambling to figure out the new IP, updating your DNS, waiting for TTLs to expire. With the CNAME, the platform updates their own DNS and your record follows automatically. So the general rule: if a service gives you a hostname to point to, use a CNAME. If they give you an IP address, use an A record. And if they give you both, use the CNAME.
What about AAAA records? We've been talking IPv4, but we're in a world where IPv6 exists.
AAAA records are just A records for IPv6 addresses. Same direct pointer concept, but for 128-bit addresses instead of 32-bit. And the same rules apply — you can't have a CNAME and an AAAA record at the same name either. The CNAME exclusivity rule covers all record types.
If you're using CNAME flattening at the apex, Cloudflare is resolving both the A and AAAA records from the target and serving them both.
The flattened response includes both IPv4 and IPv6 addresses if the target has them. The client gets a full set and can connect over whichever protocol it prefers.
The prompt also mentioned TXT records. Where do those fit into this picture?
TXT records are the utility drawer of DNS. Originally they were for human-readable text — comments, notes, whatever. But they've been repurposed for all kinds of machine-readable data. SPF records for email authentication used to be stored as TXT records before SPF got its own dedicated record type. DKIM keys for email signing are stored in TXT records. Domain verification for services like Google Workspace or Microsoft 365 — "prove you own this domain by adding this TXT record." ACME challenges for Let's Encrypt certificate issuance use TXT records.
They're the miscellaneous drawer in the kitchen that somehow ended up holding the most important things.
That's DNS in a sentence. The most critical security infrastructure on the modern internet is stored in a record type designed for human-readable notes. And here's the thing — TXT records can coexist with CNAMEs at the same name. That's an explicit exception. RFC 1034 originally said no other records with a CNAME, period. But the real world broke that rule immediately because people needed to put TXT records on domains that were CNAMEs. So the operational reality is that TXT records at a CNAME node are widely supported even if the purist reading of the spec says no.
Which is the kind of thing that makes DNS feel like a living fossil. It's got the bones of something designed in 1987, but it's accumulated all these adaptations.
Paul Mockapetris designed the DNS in 1983. He wrote the original RFCs — 882 and 883 — and the system has been running continuously since then with remarkably few fundamental changes. The record types we use today were mostly defined by 1987. The fact that we're still using them, that they still work, that the entire global economy runs on this protocol designed when the internet had a few hundred hosts — it's staggering.
Yet we're out here debating whether "www" looks dated on a business card.
The tension between technical necessity and aesthetic preference, playing out in DNS record types. It's wonderful.
Let's get concrete about the Cloudflare setup, because that's what the prompt is really asking about. Someone's got a domain, they're using Cloudflare, they want to handle encryption properly. What's the step-by-step?
Step one: you add your domain to Cloudflare. They scan your existing DNS records and import them. At minimum you'll have your apex A and AAAA records, maybe a www CNAME, and whatever MX records handle your email.
Cloudflare becomes your authoritative nameserver at that point.
You change your nameservers at your registrar to point to Cloudflare's nameservers. From that moment, Cloudflare is answering all DNS queries for your domain.
Step two: you decide whether you're using Cloudflare's proxy — the orange cloud. This is critical. When you enable the proxy on a DNS record, Cloudflare stops serving your origin server's IP address. Instead, it serves Cloudflare's own anycast IPs. Traffic hits Cloudflare's edge, gets filtered through their security rules, gets cached if possible, and then Cloudflare connects to your origin server to fetch anything it needs.
The DNS record becomes a pointer to Cloudflare, not to your server. And Cloudflare handles the actual connection to your origin behind the scenes.
And this changes how you think about encryption. Because there are now two separate connections: the client to Cloudflare, and Cloudflare to your origin. And Cloudflare gives you four SSL modes to control how those connections work.
Walk me through them.
"Off" — no encryption at all. Nobody should use this. "Flexible" — the client connects to Cloudflare over HTTPS, so the user sees the padlock, but Cloudflare connects to your origin over plain HTTP. This was popular years ago when setting up SSL on origin servers was a pain, but it's misleading because the connection to your origin is unencrypted. Cloudflare themselves recommends against it now.
The padlock is basically a lie in Flexible mode.
It's encrypting half the journey. The half that goes over the public internet between the user and Cloudflare, sure. But the half from Cloudflare to your origin — which might traverse data center networks, might cross peering points — that's in the clear. Anyone with access to that path can see the traffic.
Alright, what's next?
"Full" — the client connects to Cloudflare over HTTPS, and Cloudflare connects to your origin over HTTPS. But Cloudflare doesn't validate the certificate on your origin. It'll accept self-signed certificates, expired certificates, certificates for the wrong domain. The connection is encrypted, but Cloudflare can't verify it's actually connecting to your server and not some man-in-the-middle.
It's encrypted but not authenticated.
And then "Full Strict" — this is the one you want. Client to Cloudflare over HTTPS, Cloudflare to origin over HTTPS, and Cloudflare validates the origin certificate. It checks that the certificate is issued by a trusted CA, that it's not expired, that the domain name matches. This is end-to-end authenticated encryption.
For Full Strict, you need a valid certificate on your origin server.
You can use a certificate from a public CA like Let's Encrypt, or you can use Cloudflare's Origin CA, which issues certificates that Cloudflare's edge trusts. Cloudflare provides that for free, and it's what they recommend for origins that only receive traffic through Cloudflare.
The practical setup: apex domain has CNAME flattening pointing to whatever target, or A records pointing to Cloudflare's IPs if you're using their proxy. WWW has a CNAME pointing to the apex. Both have the orange cloud enabled. SSL mode is Full Strict. And then you configure a redirect rule.
That's the modern stack. And the redirect rule is a one-liner in Cloudflare's rules engine: if the hostname is "www dot example dot com," do a 301 redirect to "example dot com," preserving the path and query string. Or vice versa if you prefer the www version. Just pick one.
What about the actual origin server? If someone's running a web app on a VPS or a platform like Vercel or Netlify, how does that connect to this DNS setup?
If you're on a platform, they'll give you a target hostname or an IP. If they give you a hostname, you use CNAME flattening at the apex in Cloudflare. If they only give you an IP — and this still happens with some smaller hosts — you use A and AAAA records. But here's the thing: if you're using Cloudflare's proxy, the A records point to Cloudflare's IPs, not the origin IP. The origin IP is configured in Cloudflare's dashboard as the "origin server" setting. It's not visible in your public DNS.
Which means your origin server's IP isn't exposed to anyone who does a DNS lookup. That's a nice security property.
It's a significant security benefit. Attackers can't bypass Cloudflare's DDoS protection and hit your server directly because they don't know where it is. Assuming you haven't leaked the IP somewhere else — old DNS records, email headers, things like that.
The prompt also mentioned encryption settings "to the endpoint." I think that's getting at this exact distinction — the encryption between Cloudflare and your origin, not just between the user and Cloudflare.
That's where people often slip up. They set up Cloudflare, they see the padlock in their browser, they think they're done. But if they're on Flexible SSL, the traffic from Cloudflare to their origin is unencrypted. If their origin is a cheap VPS in a data center, that traffic is going over the data center's internal network. Is that network secure? Maybe, maybe not. Other tenants in the same data center might be able to sniff that traffic. The safe approach is Full Strict, always.
There's also the question of what happens at the application layer. If your web app generates links, those links need to use the canonical domain. If you've chosen the bare domain, your app needs to know that and generate "example dot com" links, not "www dot example dot com" links.
That's a configuration headache that's bitten basically everyone who's ever run a website. You set up the DNS correctly, you set up the redirect, but your WordPress installation is still generating www links in its sitemap, or your React app has the wrong base URL in its build configuration. And then you get duplicate content issues, SEO penalties, broken CORS headers. The DNS is the foundation, but the application layer has to be consistent with it.
The full picture: DNS provides the routing, Cloudflare provides the proxy and encryption, the application provides the content, and all three layers need to agree on what the canonical domain is.
If any layer disagrees, you get a broken experience that's often invisible to the site owner but obvious to users and search engines.
Let's talk about some of the edge cases. What about DNSSEC? Where does that fit into a Cloudflare-managed DNS setup?
DNSSEC adds cryptographic signatures to DNS responses so resolvers can verify that the response hasn't been tampered with. It prevents DNS spoofing attacks. Cloudflare supports DNSSEC and makes it trivially easy — there's a toggle in the dashboard. You enable it, Cloudflare generates the keys, and you add a DS record at your registrar.
Does CNAME flattening play nicely with DNSSEC?
It does, because the flattening happens before the signing. Cloudflare resolves the CNAME internally, generates the A and AAAA records, and then signs those records with DNSSEC. The resolver gets a standard, signed A record response. The CNAME never appears on the wire, so there's no CNAME to sign.
What about the case where someone is using a third-party email service — Google Workspace, Microsoft 365, Fastmail — and they want the bare domain for their website but also need MX records at the apex for email?
This is exactly why the CNAME-at-apex prohibition matters. If you could put a CNAME at the apex, you'd have a conflict: the CNAME says "follow this target for everything," but the MX records say "deliver mail here." Which one wins? The spec says you can't create this situation. So you use A records at the apex — or CNAME flattening, which produces A records — and you can freely add MX records, TXT records for SPF and DKIM, and whatever else you need. They coexist fine because there's no actual CNAME at the apex.
CNAME flattening is the thing that lets you have both a flexible web hosting setup and a properly configured email service on the same apex domain.
Before CNAME flattening, if you wanted your website on a CDN that required a CNAME target, and you also wanted email at the same domain, you had to use the www subdomain for your website. The apex was consumed by the MX records and the SOA and NS records. CNAME flattening untethered the website from that constraint.
Which is why the "www" is slowly disappearing. It was never a feature. It was a workaround that became a convention that became an anachronism.
Now it's a redirect rule. It still exists in DNS because you need to catch the people who type it, but it's not the canonical address anymore. It's a vestigial organ.
Like the appendix. Still there, occasionally causes problems, but mostly just hangs around doing nothing.
The appendix of the internet. I'm going to use that.
You're welcome. So let's talk about what happens when someone gets this wrong. What are the failure modes?
The most common one is the CNAME-at-apex violation. Someone reads a tutorial that says "create a CNAME record for your domain pointing to your hosting provider," and they go into their DNS manager and try to create a CNAME at the root. Some providers will just reject it with an error. Others will let you do it, and then weird things happen — your MX records stop working, your email disappears, and you have no idea why.
Because the CNAME is overriding everything else at that node.
And it's not always immediately obvious. DNS changes take time to propagate. You make the change on a Friday afternoon, everything seems fine, you go home, and on Monday your email has been silently failing for three days.
The Friday afternoon DNS change. The most dangerous phrase in internet operations.
Another common failure: someone enables Cloudflare's proxy on their MX record. The proxy only handles HTTP traffic. If you proxy your MX record, Cloudflare will try to handle email traffic and it won't work. Your email goes down. The fix is to make sure MX records have the proxy disabled — the gray cloud in Cloudflare's UI.
What about the SSL misconfigurations?
Flexible SSL is the big one. Site looks secure, padlock is green, but the origin connection is unencrypted. The other failure is Full SSL with an invalid origin certificate. Cloudflare can't validate the cert, the connection fails, users see an error. That's why Full Strict with a properly managed origin certificate is the goal — if something breaks, it breaks visibly, and you know to fix it.
Fail closed rather than fail open.
And the third SSL failure is mixed content. Your site loads over HTTPS, but somewhere in your HTML there's an image tag with an HTTP source, or a script loaded over HTTP. The browser blocks it, your page looks broken. That's not a DNS problem, but it's part of the same encryption story.
The prompt asked about trends. Is there anything on the horizon that's going to change how we think about DNS record types?
There are a few things. DNS over HTTPS and DNS over TLS are changing how DNS queries are transported — encrypting them so your ISP can't see what domains you're looking up. That's a privacy improvement, but it doesn't change the record types themselves. What might change things is the push toward service-oriented DNS records. Things like SRV records, which have existed forever but never got wide adoption for HTTP. SRV records let you specify not just an IP address but a port number and a priority. If browsers started supporting SRV records for HTTP, you could run your web server on a non-standard port without requiring a colon and port number in the URL.
That's been proposed for like twenty years and browsers haven't adopted it.
Because it adds a DNS lookup to every HTTP connection, and the performance cost was considered too high. But with DNS over HTTPS and faster resolvers, that calculation might change. The other thing is SVCB and HTTPS records — these are new record types, standardized in 2022, that are actually being adopted. They let you specify not just the target hostname but also protocol parameters like which version of HTTP to use, whether to use encrypted Client Hello, things like that.
Instead of connecting and then negotiating all these parameters, the DNS response tells the client what parameters to use before the connection even starts.
It collapses a round trip. And Cloudflare supports HTTPS records already. If you look in your Cloudflare DNS dashboard, you can add an HTTPS record. It's still early adoption, but it's the first genuinely new DNS record type in years that's getting real browser support.
That's the kind of thing that makes DNS feel less like a fossil and more like a platform that's still evolving.
It's evolving in a very DNS way — by adding a new record type that's backward compatible, that old resolvers can safely ignore, that doesn't break anything that already works. The whole philosophy of DNS is "don't break existing things, add new things alongside them.
Which is why we still have A records, CNAMEs, MX records, all the stuff from the eighties, coexisting with brand new record types. Nobody has to upgrade their DNS server to support the new stuff. Old servers just return what they know and ignore the rest.
It's the most successful distributed database in human history. Billions of queries per second, a total addressable namespace that covers basically every internet-connected service on the planet, and it runs on software that hasn't fundamentally changed in forty years.
Yet most people only think about it when their website goes down.
That's the sign of good infrastructure. You don't notice it until it breaks.
Alright, so to bring this back to the practical question the prompt asked. Modern best practice for someone using Cloudflare: apex domain with CNAME flattening pointing to your hosting target, www as a CNAME also pointing to the apex or the same target, both proxied through Cloudflare's orange cloud. SSL set to Full Strict with a valid origin certificate. Redirect one to the other with a 301. MX records unproxied. And your application configured to use the canonical domain consistently.
That's the playbook. And if you're on a platform that doesn't support CNAME flattening — maybe you're using a DNS provider that doesn't offer it — then you fall back to the old model: A records at the apex pointing to your provider's stable IPs, www as your primary canonical domain, redirect the bare domain to www. It's not as clean, but it works.
The www version still works fine. It's just aesthetically out of fashion.
Fashion is temporary. DNS is forever.
That might be the most Herman Poppleberry thing you've ever said.
I stand by it.
One more thing I want to touch on. The prompt mentioned that DNS record types have remained "remarkably stable." Is that actually true, or is it just that the core types have stayed the same while everything around them has changed?
It's both. The core types — A, AAAA, CNAME, MX, NS, SOA, TXT, PTR, SRV — these were all defined decades ago and they still work exactly the same way. The stability is real. But the ecosystem around them has transformed completely. The way records are managed, the tools we use, the scale at which they're queried, the security infrastructure layered on top — all of that is unrecognizable from 1987.
The grammar of DNS is stable. The vocabulary hasn't changed. But the literature being written with it is completely different.
That's a very Corn way to put it. The grammar is stable. And that stability is a feature, not a bug. It means that a DNS record created in 1995 still resolves correctly today. It means that every internet-connected device, from a mainframe to a smart lightbulb, speaks the same protocol. That kind of interoperability is vanishingly rare in technology.
It's the Latin of the internet. Dead in the sense that it's not changing, but somehow still doing more actual work than most living languages.
Just like Latin, everyone who studies it develops strong opinions about the correct way to use it, and then the real world ignores those opinions and does whatever works.
The RFCs are the grammar textbooks. The actual DNS traffic on the wire is the living language.
The living language includes things like CNAME flattening, which is technically a violation of the conceptual model but works perfectly in practice and solves a real problem.
The descriptivist versus prescriptivist debate, playing out in internet infrastructure.
I'm firmly in the descriptivist camp on this one. If it works, if it doesn't break anything, if it makes people's lives easier, then it's correct.
Yet you're the one who reads RFCs for fun.
I contain multitudes.
I think we've covered the landscape. DNS fundamentals, the CNAME versus A record distinction, the apex problem, CNAME flattening, Cloudflare setup, encryption from client to origin, and what's coming next with HTTPS records.
The appendix of the internet.
I regret that metaphor already.
It's out there now.
Now: Hilbert's daily fun fact.
Hilbert: In the Azores, katabatic winds can rush down volcanic slopes fast enough that a person walking into them would feel an apparent temperature drop equivalent to moving from a warm spring afternoon to near-freezing in under two minutes. That's roughly a twelve-degree Celsius drop per minute of sustained exposure.
I feel like Hilbert is trying to prepare us for something.
Or warning us about a very specific vacation destination.
This has been My Weird Prompts. Thanks to our producer Hilbert Flumingtop. You can find the show at myweirdprompts dot com. We'll be back with another one soon.
Until then, may your DNS resolve correctly and your CNAMEs never conflict.
