DNS for custom domain: live site down, email working fine 🤔

Hello,

For some reason my site (codemacabre.com) is down. The default netlify subdomain is fine (https://codemacabre.netlify.app/), it’s just my custom domain which seems to be having issues.

Oddly enough, my email which uses the same service isn’t having any problems.

There were no DNS changes on my end before the site went down. I’ve since tried deleting and re-adding all records, nameservers, etc. on both my registrar and in the netlify settings but no luck. It’s been about 48 hours with no improvement.

Unless I’ve missed something obvious, could you take a look behind the scenes and see what’s put a spanner in the works, please?

The website seems to load fine for me. What error are you seeing?

It does? I either get a 404 blank page or unable to connect entirely:

It doesn’t load in any browser or device here (and several other UK-based folks I’ve asked to check for me). Surely it’s not a regional thing?

This is what I got.

I wouldn’t think so, but you can wait for a better answer. The issue is really strange to be honest.

@codemacabre I’m seeing the same thing here in Southern California that @hrishikesh posted. Your DNS looks fine, so if you’re seeing something different, it may be regional, or maybe something to do with your local setup.

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I don’t think this is a regional issue since I’m UK based without a VPN.

This is weird man.

This is what your site looks like according to GTMetrix:

downforeveryoneorjustme.com report:

Down.com report:

Found no inconsistencies, Everything seems to be working.

I know it seems obvious but have you tried the site on:

different devices
different internet providers
cellular/wi-fi connections
with/without VPN

I just turned my wifi off and it works on mobile data. Could it be my ISP? @kylesloper are you using Virgin Media by any chance?

I am using TalkTalk. I have a feeling this is your ISP.

In that case it could mean you might have parental locks on or they are just blatantly blocking your site on their network ://

Hey @codemacabre :wave:t2:

As the old adage goes, it’s always DNS :slight_smile:

Yes, it could be your ISP. The way DNS works implements caching at every layer, including your ISP’s DNS servers and your local DNS cache. If you switched off to cellular (a good tactic for debugging, nice call!) and it worked, it would show that your ISP’s DNS cache was holding onto that value.

The funny part is now that your mobile device got the right IP, it probably logged it to its local DNS cache and once you connect back to the wi-fi / ISP, it’ll still resolve fine because your mobile device won’t reach out to the ISP’s DNS again (it’s already cached!)

This is a good exercise in understanding DNS TTL’s though; this guide that Luke wrote is a great explainer of how to wield the powers of TTL


Jon

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As explained here they state that they do actually block certain sites from their network.

Your best shot it to contact customer service since you must be losing significant numbers of traffic.

Quick question, what service is your cellular on? Is it Virgin Media or is it another company?

Oh look It seems @jonsully just posted a great comment that seems to sum up the situation. If his method doesn’t work then I strongly advise reaching out to VirginMedia.

Dang. I know that some ISP’s will automatically intercept non-resolving DNS requests and forward you to their own search engine instead of letting your browser totally fail (which I always disable for these reasons) but I’ve never heard of an ISP (cellular or land) just straight up blocking DNS for particular domains. That’s not cool :eyes:

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@codemacabre It could also be browser caching or local DNS caching. Have you tried visiting your site in a private / incognito window?

Yeah, no dice. It’s been suggested it might be an issue with my ISP caching the DNS on your home connection, so I’m going to try unplugging that for a while.

Not sure why it’d be affecting others though, unless I accidentally broke the settings when trying to fix the issues here.

This seems to be resolved. I’m pretty sure it was a combination of a few things:

  1. Initial DNS issue caused by something unknown. Several folks local to UK informed me my site was down
  2. Tinkered with various settings which either fixed then broke, or just plain broke the DNS
  3. Tinkered further which fixed the DNS (which is why it worked for you lot) but got stuck in my ISP’s cache
  4. Unplugged my router overnight.

I’m still not sure what caused the initial problem, but no matter all seems fine now. Thanks for your help everyone! :raised_hands:t3:

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Hi, @codemacabre. The only other thing I can think of that it possibly could have been that fix this was enabling IPv6 for the DNS zone. Some mobile/wireless ISPs provide IPv6 connectivity only so it could be enabling that which resolved the DNS issues.

This is just a thought. I don’t know for sure what it was because DNS doesn’t have a history for me to check.