Static WordPress Community

ANAME v/s Actual CNAME

If a CDN IP changes as per region,

  • Go for www (Actual CNAME)
  • Go for non-www (ANAME)

0 voters

I’d recommend going with www. Here’s why

image

At the moment of writing, I use BunnyCDN.

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Re ANAME, for a case like this, the key is in the EDNS Client Subnet from your authoritative DNS. Meaning that authoritative DNS needs to resolve IP(s) from a specified CNAME first, then we get answers from authoritative DNS, not the CNAME’s DNS. Answers you received are as far as authoritative DNS POPs. ANAME is a CNAME proxy to get A and AAAA. FQDN -> IP addresses.

It’s hard to define ANAME done wrong if we don’t see the current setup of our own DNS. Authoritative DNS must support EDNS client subnet for more geo-accurate query routing.

Some I can suggest in the case of using ANAME:

  • Use ANAME when you know CNAME is anycast IP(s).
  • Use ANAME when you know your authoritative DNS has enabled Client Subnet.
  • Use ANAME when you want to increase the TTL to get benefits of faster DNS resolving and also saving the DNS server bandwidth.

Nowadays I often use anycast IPs so I will choose ANAME :slight_smile:

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@frans this goes over my head a bit. Can I ask as lay person:

ANAME will allow apex domain to fully use CDN, but only if they support it with their internal DNS setup?

re these:

  • Use ANAME when you know CNAME is anycast IP(s).
  • Use ANAME when you know your authoritative DNS has enabled Client Subnet.

how can we confirm for a CDN provider?

I am using BunnyCDN. They do not provide own NS like or any particular Static IP. I am on the mercy of CNAME Flattening done by Cloudflare. :thinking:

The above problem doesn’t happen with all ISPs but with some ISPS. I highly doubt if those support EDNS.

ANAME on Apex works with CDNs, if we use authoritative DNS that support for EDNS. Doesnt matter how CDN’s internal DNS works.

For example I use Cloudflare DNS for example.com (apex), then point to Bunny (example.b-cdn.net). Since Cloudflare supports EDNS, the IP results should be accurate.

Checked your NS, Cloudflare? Maybe when you did the test, you got Korean POP?

Exactly. I am using CF NS. That time at other ISP airtel, routing was fine but at Jio it was going off.

Ah make sense, I checked from here. Re your domain. Apex looks good. Maybe I got nearest Cloudflare POP.

How reliable is Cloudflare CNAME Flattening for BunnyCDN?

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Let’s find out

Step 1. Which Public DNS Resolver do you use?

It should not be Google/Cloudflare My problem of off-routing is limited to local ISP DNS.

Step 2. Lookup IP for gulshankumar.net

Linux/Mac Terminal

dig gulshankumar.net

Windows CMD

ping gulshankumar.net

Android App:

Thanks in advanced for helping in debugging.

x230$ dig gulshankumar.net

; <<>> dig 9.10.8-P1 <<>> gulshankumar.net
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 13378
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;gulshankumar.net.              IN      A

;; ANSWER SECTION:
gulshankumar.net.       35      IN      A       185.190.83.2

;; Query time: 170 msec
;; SERVER: 10.1.1.1#53(10.1.1.1)
;; WHEN: Sun Jun 28 05:54:56 ACST 2020
;; MSG SIZE  rcvd: 61
x230$ ping gulshankumar.net
PING gulshankumar.net (185.190.83.2): 56 data bytes
64 bytes from 185.190.83.2: icmp_seq=0 ttl=58 time=17.151 ms
64 bytes from 185.190.83.2: icmp_seq=1 ttl=58 time=16.641 ms
64 bytes from 185.190.83.2: icmp_seq=2 ttl=58 time=16.765 ms
64 bytes from 185.190.83.2: icmp_seq=3 ttl=58 time=17.404 ms
64 bytes from 185.190.83.2: icmp_seq=4 ttl=58 time=16.801 ms
64 bytes from 185.190.83.2: icmp_seq=5 ttl=58 time=16.826 ms
64 bytes from 185.190.83.2: icmp_seq=6 ttl=58 time=16.643 ms
64 bytes from 185.190.83.2: icmp_seq=7 ttl=58 time=17.198 ms
64 bytes from 185.190.83.2: icmp_seq=8 ttl=58 time=16.563 ms
64 bytes from 185.190.83.2: icmp_seq=9 ttl=58 time=16.416 ms
64 bytes from 185.190.83.2: icmp_seq=10 ttl=58 time=15.870 ms
64 bytes from 185.190.83.2: icmp_seq=11 ttl=58 time=16.428 ms
64 bytes from 185.190.83.2: icmp_seq=12 ttl=58 time=16.827 ms
64 bytes from 185.190.83.2: icmp_seq=13 ttl=58 time=16.534 ms

That’s from some Aus ISP, thanks to my neighbour’s donated wifi

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I tested in multiple mobile devices with Jio SIM, all were facing off-routing.

Therefore, I have decided to stick with www for the most reliable experience.

Thanks everyone for testing.

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