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58 votes
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I changed my TTL from 24 hours to 5 minutes. Do I need to wait 24 hours before changing the records?

Anyone who has a cached copy of the domain record will not bother updating it for 24 hours, so yes if your intent is to have at most a 5 minute window of unavailability you should wait until all of ...
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39 votes

I changed my TTL from 24 hours to 5 minutes. Do I need to wait 24 hours before changing the records?

It's (potentially) even worse than that -- you have to wait 24 hours after all of your authoritative servers have updated. The normal way for updates to happen is that you make a change to the zone on ...
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23 votes

I changed my TTL from 24 hours to 5 minutes. Do I need to wait 24 hours before changing the records?

Yes, you should wait. Even then of course it's not guaranteed that everyone will respect the TTL.
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22 votes
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What happens when your TTL gets screwed up in your DNS record?

Ryan has provided an excellent answer to one interpretation of your question. Given our target audience however, and the situation of the people most likely to stumble upon the question, I'm going to ...
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  • 31.5k
16 votes

What happens when your TTL gets screwed up in your DNS record?

Well, first of all the Bind configuration manual I'm looking at states that TTL is a signed 32-bit integer, expressed in seconds, giving it a theoretical maximum of 2^31. It says Valid TTLs are of ...
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  • 54.8k
12 votes
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Is there a standard time duration before DNS caches are cleared?

You'll be happy to know that most (if not all) DNS server software has protection against this scenario. For example: Microsoft DNS server has a MaxCacheTTL setting, which defaults to 86400. So ...
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9 votes
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Is low TTL an appreciable burden on DNS?

FWIW, many browsers cache the DNS info for a site and don't honor TTL limits. But some do so Yes, a compliant browser/OS should refresh the info after 5 minutes. However, it's unlikely they would ...
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8 votes

Recommended DNS SOA record TTL default?

From Pingdom: http://dnscheck.pingdom.com/ SOA TTL recommended >= 3600. SOA refresh recommended >= 14400. SOA retry recommended >= 3600. SOA expire recommended >= 604800. SOA minimum ...
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  • 81
7 votes
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Why does TTL sometimes re-increment between DNS queries?

Dig reports the time left until the TTL expires rather than the actual TTL value. If the number varies, it is most likely that you're querying different DNS servers (for example, round robin) which ...
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  • 9,330
6 votes

What does the TTL on a CNAME record mean?

All you CNAME records will be cached for a maximum of 3600, 10800 and 21600 seconds. The A records are handled independently and will be queried again every 60 seconds. However, in case the CNAME ...
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6 votes
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AWS Route 53 alias-record change takes too long

Firstly, it's important to recognise that the DNS records cached on the client or their DNS resolver which are both out of your control (note that I'm referring to the DNS records not your ...
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  • 1,849
6 votes
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Best CNAME TTL strategy for fallover switching

Assuming that the apex A record for example.com. was pointing at a broken IP address, most companies I know would change the A record and skip the www change entirely: Most admins would rather not ...
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6 votes
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Moving DNS hosting for Active site to Route 53 - with G Suite MX TTL of 1 week

As long as you create the MX record exactly the same in Route53 as it currently is in GoDaddy you don't need to change its TTL. Likewise with all the other records - A, CNAME, etc. Only NS records ...
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  • 23.3k
5 votes
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TTL in ping vs dig

The TTL with ping has an entirely different meaning then for DNS. For DNS, it means how long a record may be cached before it is to be considered too old. The value for ping means how many hops the ...
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  • 96.4k
5 votes
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NSCD TTL and DNS TTL, which one is stronger?

It's important to note that nscd acts as a cache for the resolver system in general, not specifically for DNS lookups but all means of name lookups. As a result of this, nscd has historically had ...
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5 votes
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Lowering TTL on nameserver, not registrar, then changing nameservers?

A better way to accomplish what you want might be to, if possible, match the records in both name servers then switch the name servers first. That way no matter what name server the client gets it ...
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  • 1,309
5 votes

I changed my TTL from 24 hours to 5 minutes. Do I need to wait 24 hours before changing the records?

Pulling together various comments and answers the complete procedure would be something like. Make sure you can update your authoratative servers in a timely manner. Reduce the TTL. Check all ...
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  • 4,018
5 votes

I changed my TTL from 24 hours to 5 minutes. Do I need to wait 24 hours before changing the records?

In addition to the other answers, you can use https://www.whatsmydns.net/ to check how your DNS record is propagating in almost real time.
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4 votes
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Bouncing email due to bad initial MX TTL?

Never shutdown the old server until you know that the TTL of the MX record pointing to the old server has expired. If the TTL is/was 1 week then leave the old server running for 1 week to catch any ...
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  • 107k
4 votes
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TTL and Google DNS

The reason why different TTLs are shown at different query is that 8.8.8.8 is a (Virual IP) load balancer which has many DNS servers attached to it. And so every new request that arrive lands on ...
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4 votes
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possible to see remaining DNS negative cache for domain?

There is no query based way to get server state. Glue, negative cache timers, etc. must be dumped from memory using the rndc dumpdb command. Record types beginning with \- are negatively cached. \-A, ...
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  • 31.5k
4 votes

What happens when multiple MX records in a DNS name have different TTLs?

The scenario that you describe is not a valid record set. A single RRset (the set of records for a specific name,class,type combination) is not allowed to have differing TTLs for its individual ...
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3 votes

How to find the initial values of TTL for your current operating system?

Packets sent to localhost don't go over any hops so the ttl shown will be the starting value. Windows 10 C:\>ping -4 localhost Pinging Win10Main [127.0.0.1] with 32 bytes of data: Reply from ...
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  • 3,366
3 votes
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Why is TTL increasing? (and generally behaving erratically)

The hop limit (or TTL) is decreased at each hop (unless something in your network is seriously broken). The values you are seeing are not from the packets you are sending, but rather from the replies ...
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  • 29.7k
3 votes

Recommended DNS TTL

(note: this post applies to the TTL on the indidivual A/AAAA records, some other record types can have longer TTLs because they don't represent single points of failure in the same way). You really ...
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  • 4,018
3 votes
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How long does it take to update TTL (Time To Live) of a domain

it can take up to that 86400 but not all recursive dns servers strictly follow ttl values, especially for 60 (expect ttl no lower than 300 real world). rule of thumb is 48 hours, actual results will ...
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  • 7,515
2 votes

How do I set a varnish response TTL dynamically?

According to the Varnish documentation you can use the Cache-Control header. Cache-Control The 'Cache-Control' header instructs caches how to handle the content. Varnish cares about the max-...
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  • 121
2 votes
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Outlook.com DNS so slow, postfix times out

I had options timeout:1 attempts:1 in my resolv.conf. Changing the timeout to 3 seconds instead of one solved the problem: options timeout:3 attempts:1 And be sure not to have this line in your main....
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  • 1,435
2 votes

Big Trouble with (I think) Outlook X500 addressing

As one of the crucial step for migration from on-prem mail exchange server to Office365, the TTL value should be lowered to a minimal time from the default value during the update change of the MX ...
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  • 554

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