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I know that it is not usual, but could I use dinamic IP address on a server that is running a DHCP Server instead of setting a static IP address on it? Is there a restriction of my Windows DHCP server?

Diogo
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  • Why would you ever want to do this? Please take a peek at our [faq]. It clearly states: `"You should only ask practical, answerable questions based on actual problems that you face"` If this is, indeed, a problem that you actually face, then you're doing something very wrong. – MDMarra Mar 14 '12 at 18:45
  • "I am not able rightly to apprehend the kind of confusion of ideas that could provoke such a question." - Charles Babbage – Joel E Salas Mar 14 '12 at 18:47
  • Actually my question is asking if it is possible to have a server with dhcp server using an ip adress that came from itself... I'm asking about possibilities and technical limitations... If you want I would ask this on SuperUser, but I thought that I needed to ask questions about server here on ServerFault... Free fell to migrate, delete, close, whatever... – Diogo Mar 14 '12 at 18:52

2 Answers2

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If you are asking if a DHCP server can assign itself a dynamic address then the answer is NO. The DHCP server needs to know the IP of the interface the request was received on for it to decide which scope to use for returning the address. A DHCP server couldn't assign address to itself, because it would have no way to figure out which scope to use.

I suppose it may be possible to have another DHCP server offer the address for the box, but that seems like a very silly idea. I am not sure if Windows would permit that though. I know you get lots of warnings when you install DHCP while you still have a dynamic address.

Zoredache
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  • So the same server running a DHCP server will never get an IP address from itself? It is a tecnical restriction? There is some standard about it? – Diogo Mar 14 '12 at 18:10
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    Not sure if you saw my update, but it includes a description why. Basically it has to do with the fact that DHCP can serve many different scopes. Without knowing the IP of the interface the DHCP request was received on, the DHCP server cannot decide which scope to use. – Zoredache Mar 14 '12 at 18:12
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DHCP works through a process Discover-Offer-Request-Acknowledge (DORA). When a client is joined to a network, it discovers if there is a DHCP server in the network. . So technically if you dont have an IP address for the server, clients (which includes the server itself) cannot Discover it. For DHCP to work, it needs an IP address and pool of addresses it can lease

Minumula
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