Problems with low DNS TTLs
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Problems with low DNS TTLs
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Re: Problems with low DNS TTLs
#2What is the use cases for having the TTL shorter than 5 minutes?
Re: Problems with low DNS TTLs
#3What is the use cases for having the TTL shorter than 5 minutes?
[deleted]
Re: Problems with low DNS TTLs
#4[deleted]
Re: Problems with low DNS TTLs
#5What is the use cases for having the TTL shorter than 5 minutes?
The article posits why:
Why are DNS records set with such low TTLs?
- Legacy load balancers left with default settings
- The urban legend that DNS-based load balancing depends on TTLs (it doesn’t - since Netscape Navigator, clients pick a random IP from a RR set, and transparently try another one if they can’t connect)
- Administrators wanting their changes to be applied immediately, because it may require less planning work.
- As a DNS or load balancer administator, your duty is to efficiently deploy the configuration people ask, not to make websites and services fast.
- Low TTLs give peace of mind.
- People initially use low TTLs for testing, and forget to crank them up later.
Re: Problems with low DNS TTLs
#6What is the use cases for having the TTL shorter than 5 minutes?
I always was under the impression people lowered the TTL when updating records... which doesn't even really make sense since the change won't propagate until the previous TTL is overrun anyways.
Then you were supposed to update it to a longer TTL when your change had propagated.
So, I guess, after understanding things better... there is no use case really since if it's a new record your change will always propagate, and if it's an old record, lowering the TTL on update doesn't really matter since the old TTL will still be in effect.
Re: Problems with low DNS TTLs
#7What is the use cases for having the TTL shorter than 5 minutes?
The article posits why: Why are DNS records set with such low TTLs? - Legacy load balancers left with default settings - The urban legend that DNS-based load balancing depends on TTLs (it doesn’t - since Netscape Navigator, clients pick a random IP from a RR set, and transparently try another one if they can’t connect) - Administrators wanting their changes to be applied immediately, because it may require less plann…
But those are no valid use cases which was my question. So there are no valid use cases at all?
Re: Problems with low DNS TTLs
#8Earlier quoted context omitted.
The article posits why: Why are DNS records set with such low TTLs? - Legacy load balancers left with default settings - The urban legend that DNS-based load balancing depends on TTLs (it doesn’t - since Netscape Navigator, clients pick a random IP from a RR set, and transparently try another one if they can’t connect) - Administrators wanting their changes to be applied immediately, because it may require less plann…
But those are no valid use cases which was my question. So there are no valid use cases at all?
> Administrators wanting their changes to be applied immediately, because it may require less planning work.
Why is this not valid?
Re: Problems with low DNS TTLs
#9What is the use cases for having the TTL shorter than 5 minutes?
I always was under the impression people lowered the TTL when updating records... which doesn't even really make sense since the change won't propagate until the previous TTL is overrun anyways. Then you were supposed to update it to a longer TTL when your change had propagated. So, I guess, after understanding things better... there is no use case really since if it's a new record your change will always propagate,…
You could lower TTL if you know a change is coming.
Re: Problems with low DNS TTLs
#10Earlier quoted context omitted.
The article posits why: Why are DNS records set with such low TTLs? - Legacy load balancers left with default settings - The urban legend that DNS-based load balancing depends on TTLs (it doesn’t - since Netscape Navigator, clients pick a random IP from a RR set, and transparently try another one if they can’t connect) - Administrators wanting their changes to be applied immediately, because it may require less plann…
But those are no valid use cases which was my question. So there are no valid use cases at all?
A low DNS TTL for testing purposes is a valid use case.