DNS Update Issue
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@Dashrender said in DNS Update Issue:
That second part is also wrong - they flip back when whatever event caused them to flip in the first place happens in again. But when you're using public DNS as a secondary entry - you're instantly broken, and once you discover you're broken who's going to wait around until whatever caused the flip to happen to happen again?
You mean an opposite event? Meaning... they stay forever, until something breaks?
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Testing now, because I want to know...
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@scottalanmiller said in DNS Update Issue:
Testing now, because I want to know...
On non-Windows (Fedora specifically) it goes back instantly. The moment the original server is back, it is using it. And always uses it when available.
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@scottalanmiller said in DNS Update Issue:
@scottalanmiller said in DNS Update Issue:
Testing now, because I want to know...
On non-Windows (Fedora specifically) it goes back instantly. The moment the original server is back, it is using it. And always uses it when available.
cool - nice to know.. I wonder why Windows doesn't do that.
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@Dashrender said in DNS Update Issue:
@scottalanmiller said in DNS Update Issue:
@scottalanmiller said in DNS Update Issue:
Testing now, because I want to know...
On non-Windows (Fedora specifically) it goes back instantly. The moment the original server is back, it is using it. And always uses it when available.
cool - nice to know.. I wonder why Windows doesn't do that.
Time-To-Live is shorter?
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Or it something to do with Fedora using mDNS and avahi.
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@black3dynamite said in DNS Update Issue:
@Dashrender said in DNS Update Issue:
@scottalanmiller said in DNS Update Issue:
@scottalanmiller said in DNS Update Issue:
Testing now, because I want to know...
On non-Windows (Fedora specifically) it goes back instantly. The moment the original server is back, it is using it. And always uses it when available.
cool - nice to know.. I wonder why Windows doesn't do that.
Time-To-Live is shorter?
TTL isn't used at all. TTL doesn't apply to DNS selection in this case.
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@Dashrender said in DNS Update Issue:
@scottalanmiller said in DNS Update Issue:
@scottalanmiller said in DNS Update Issue:
Testing now, because I want to know...
On non-Windows (Fedora specifically) it goes back instantly. The moment the original server is back, it is using it. And always uses it when available.
cool - nice to know.. I wonder why Windows doesn't do that.
The logic is probably something from the 1990s that no one has addressed again to deal with how things should reasonably work in the modern world.
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@black3dynamite said in DNS Update Issue:
Or it something to do with Fedora using mDNS and avahi.
More likely just Windows being the odd man out here. I expect everyone else behaves like Fedora. It's just a way more logical, and simple, approach.
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Does anyone know what event causes this in Windows?
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@wirestyle22 said in DNS Update Issue:
Does anyone know what event causes this in Windows?
Cause what, the NIC to flip? I've heard Windows people say that it's just a bug and it does it randomly. I know that it could happen from a DNS server being unavailable for a split second, just long enough to fail a lookup.
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@scottalanmiller said in DNS Update Issue:
@wirestyle22 said in DNS Update Issue:
Does anyone know what event causes this in Windows?
Cause what, the NIC to flip? I've heard Windows people say that it's just a bug and it does it randomly. I know that it could happen from a DNS server being unavailable for a split second, just long enough to fail a lookup.
That was my initial thought. So what--Linux OSes are checking periodically to see if they are using the first entry and Windows doesn't care until there's a hiccup?
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@wirestyle22 said in DNS Update Issue:
@scottalanmiller said in DNS Update Issue:
@wirestyle22 said in DNS Update Issue:
Does anyone know what event causes this in Windows?
Cause what, the NIC to flip? I've heard Windows people say that it's just a bug and it does it randomly. I know that it could happen from a DNS server being unavailable for a split second, just long enough to fail a lookup.
That was my initial thought. So what--Linux OSes are checking periodically to see if they are using the first entry and Windows doesn't care until there's a hiccup?
Linux checks every time, I believe. That's the expected behaviour. It always uses its list top to bottom, it doesn't "change" primary just because it wants to.
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@scottalanmiller said in DNS Update Issue:
@wirestyle22 said in DNS Update Issue:
@scottalanmiller said in DNS Update Issue:
@wirestyle22 said in DNS Update Issue:
Does anyone know what event causes this in Windows?
Cause what, the NIC to flip? I've heard Windows people say that it's just a bug and it does it randomly. I know that it could happen from a DNS server being unavailable for a split second, just long enough to fail a lookup.
That was my initial thought. So what--Linux OSes are checking periodically to see if they are using the first entry and Windows doesn't care until there's a hiccup?
Linux checks every time, I believe. That's the expected behaviour. It always uses its list top to bottom, it doesn't "change" primary just because it wants to.
See this just seems odd to me - why add in that delay every time. The way windows does it - once it flips it doesn't flip back until the current DNS server blips - makes sense. Stay stable, stay on what is working.
There shouldn't be an issue with this - assuming your DNS setup is correct.But flipping back each and every time adds latency to your DNS queries for at best a minor benefit (again, assuming a correctly setup DNS environment).
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@Dashrender said in DNS Update Issue:
@scottalanmiller said in DNS Update Issue:
@wirestyle22 said in DNS Update Issue:
@scottalanmiller said in DNS Update Issue:
@wirestyle22 said in DNS Update Issue:
Does anyone know what event causes this in Windows?
Cause what, the NIC to flip? I've heard Windows people say that it's just a bug and it does it randomly. I know that it could happen from a DNS server being unavailable for a split second, just long enough to fail a lookup.
That was my initial thought. So what--Linux OSes are checking periodically to see if they are using the first entry and Windows doesn't care until there's a hiccup?
Linux checks every time, I believe. That's the expected behaviour. It always uses its list top to bottom, it doesn't "change" primary just because it wants to.
See this just seems odd to me - why add in that delay every time. The way windows does it - once it flips it doesn't flip back until the current DNS server blips - makes sense. Stay stable, stay on what is working.
There shouldn't be an issue with this - assuming your DNS setup is correct.But flipping back each and every time adds latency to your DNS queries for at best a minor benefit (again, assuming a correctly setup DNS environment).
See, you say "little benefit" in the midst of a whole thread about how Linux works beautifully because of this and Windows is flaky and unreliable. Can't be both. Either Windows works and all of that is BS, or clearly this isn't a trivial thing. The DNS delay only happens when your set primary is down, which is almost never in the modern world. If you have issues that your DNS is always down, stop using it as your primary.
You are using something that isn't a real world problem and acting like it affects someone when it doesn't, while ignoring a real world problem that has clearly impacted nearly everyone in this thread (and others, this has come up multiple times in the last few weeks alone) that this behaviour solves.
So I think it's pretty clear why Linux chooses to work the way that it does, and extremely clear why it is what we'd always prefer.
The Windows way only makes sense under the assumption that you always are using internal DNS, not public, and that you have only local DNS servers in your pool. It's most useful only under a very specific set of circumstances where you are going with AD and LAN-based, and you have redundancy locally, not redundancy over a WAN link like many SMBs do.
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Well - frankly - I have no clue how much of a real issue this is any more. I haven't had incorrectly setup DNS in ages.
I suppose I could setup my PC with google for a secondary, then what - make a script that tries pinging one of my internal resources by DNS name and see if/ever it fails?
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@scottalanmiller said in DNS Update Issue:
(and others, this has come up multiple times in the last few weeks alone)
It has? where?
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@scottalanmiller said in DNS Update Issue:
It's most useful only under a very specific set of circumstances where you are going with AD and LAN-based, and you have redundancy locally, not redundancy over a WAN link like many SMBs do.
Or the opposite - home users who generally only have public DNS servers. or travelers who also only generally have public DNS servers.
In fact, this is only an issue for those who do have internal DNS servers with internal only records.
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@Dashrender said in DNS Update Issue:
Well - frankly - I have no clue how much of a real issue this is any more. I haven't had incorrectly setup DNS in ages.
I suppose I could setup my PC with google for a secondary, then what - make a script that tries pinging one of my internal resources by DNS name and see if/ever it fails?
It's enough of an issue that everyone recommends not having public failover from clients because they perceive it as simply not workable. So either it's actually a big deal, or all that advice is wrong.
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@Dashrender said in DNS Update Issue:
@scottalanmiller said in DNS Update Issue:
(and others, this has come up multiple times in the last few weeks alone)
It has? where?
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