Stupid question: what is DHCP-Authoritative

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sparrowkc
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PostPosted: Thu Nov 16, 2006 22:32    Post subject: Stupid question: what is DHCP-Authoritative Reply with quote
I'm sorry to ask such a basic question, but I promise I have searched The wiki and google several different ways and I cannot figure this out.


What is DHCP-Authoritative? What does it do? What are it's uses?


If there is a Wiki entry please just give me the link, and I will feel stupid.
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DrRossi
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PostPosted: Fri Nov 17, 2006 1:58    Post subject: Reply with quote
Well, the first google result for a search for "DHCP-Authoritative" returns this link:
ISC DHCP Authoritative Clause
http://www.isc.org/index.pl?/sw/dhcp/authoritative.php

Well, ok, Google does not return the same result everywhere, and the rest of the results doesn't look so great.

In short the authoritative clause means that if your DHCP server is the only one on your network (as is nearly always the case), it KNOWS what the valid IP numbers on its network are, and if a client tries to register with an invalid IP number (laptop still has lease from another network) , it immediately tells the client to f*** o** , um, reset itself and try afresh, instead of doing nothing, and leaving it to the client to timeout.

So DHCP-Authoritative should nearly always be set.
I didn't know that.
sparrowkc
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PostPosted: Fri Nov 17, 2006 3:02    Post subject: Reply with quote
Thanks!

I understand that article now, but when I found it earlier I couldn't make sense of it.
wo-fo
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PostPosted: Fri Nov 17, 2006 16:24    Post subject: Reply with quote
Cool.. We learn something new every day....

Thanks,
wo-fo
EncryptedBytes
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PostPosted: Tue Oct 27, 2009 0:41    Post subject: Reply with quote
Just an FYI...

This thread is presently the 2nd Google result for "DHCP-Authoritative". Thanks for answering my question, even if it was 3 years before I asked :C)

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endstille
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PostPosted: Thu Nov 11, 2010 20:57    Post subject: Reply with quote
Just an FYI...

Now it is Rank one.
I can only agree to EncryptedBytes.
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Jamby
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PostPosted: Sun Nov 21, 2010 20:27    Post subject: Thanks Reply with quote
Thank you DrRossi
tno
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PostPosted: Sun Dec 05, 2010 11:59    Post subject: So, if I'm using a switch in addition to my router . . . Reply with quote
I should turn this off, yes? Because then there are two DHCP's and you don't want to ever cross the streams. Yes? Let me know.
frater
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PostPosted: Sun Dec 05, 2010 12:57    Post subject: Reply with quote
What useless input to a 4 year old thread.
Leave it alone if you have nothing sensible to add.

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tno
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PostPosted: Sun Dec 05, 2010 13:12    Post subject: No need to be rude Reply with quote
I was asking a question. If you don't have an answer you're welcome to excuse yourself from the thread.

For anyone else, I am still unsure whether this setting should be on or off if I add a switch to my set-up. Any help would be appreciated. Any hate will be ignored.

frater wrote:
What useless input to a 4 year old thread.
Leave it alone if you have nothing sensible to add.
frater
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PostPosted: Sun Dec 05, 2010 13:22    Post subject: Reply with quote
The answer is no.
It was answered 4 years ago already if you took the time to read it properly.
You may have a special situation, but then you should have described it in your question.

BTW... I was also referring to the posts in 2009 and previous posts in 2010 about Google ranking.

@moderator: please delete posts after 2006 and close it. It may be easier for some people to see the question has been answered. It seems some have trouble finding it...

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GeeTek
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PostPosted: Sun Dec 05, 2010 15:38    Post subject: Reply with quote
tno wrote:
I was asking a question. If you don't have an answer you're welcome to excuse yourself from the thread.


Please excuse Frater.

frater wrote:
@moderator: please delete posts after 2006 and close it.


Being a hard core nerd like yourself, I haven't had sex in several years either. I suggest you start drinking heavily and quit taking this forum foo shit so seriously.
Shocked

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phuzi0n
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PostPosted: Sun Dec 05, 2010 23:27    Post subject: Re: So, if I'm using a switch in addition to my router . . . Reply with quote
tno wrote:
I should turn this off, yes? Because then there are two DHCP's and you don't want to ever cross the streams. Yes? Let me know.

You should almost never have two DHCP servers on the same layer 2 segment and if you do then they need to be configured to not contend with each other. DHCP Authoritative is important if you have any devices that roam to other networks like a smartphone or laptop you use at multiple locations. The only reason not to use it is that if two DHCP servers are on the same layer 2 segment and either is configured to be Authoritative then it will invalidate the other's attempts to give leases. Only really complex networks need to worry about having it disabled. It's also commonly disabled in DHCP servers by default to avoid noobies plugging an Authoritative DHCP server into an existing network and bringing it down but you really ought to have it enabled.

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dfroelicher
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PostPosted: Wed Nov 16, 2011 5:37    Post subject: Reply with quote
just to revive a dead thread, I have found that with the spaceship looking black Linksys Wrt54g that if this is left on it will eventually overwhelm the little guy and make your dns stop working.

At least in my case, switch on no internet, switch off lots of internet. Go with the second one Laughing
elorimer
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PostPosted: Mon Nov 28, 2011 1:21    Post subject: Reply with quote
Googling the same question brought me here.

Thanks, phuzi0n, that was very helpful. Setting DHCP Authoritative to "on" seems to have settled a problem I've been having with a Galaxy Tab on froyo, which frequently would refuse to reconnect to my home wireless network.

(Reading the thread, I laughed that the answer, authoritatively delivered, to "on or off" was "no".)
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