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Questions tagged [dhcp]

DHCP stands for Dynamic Host Configuration Protocol and is an auto configuration protocol used on IP networks and an extension of the Bootstrap Protocol.

The Dynamic Host Configuration Protocol (DHCP) is an auto configuration protocol used on IP networks and an extension of the Bootstrap Protocol. DHCP allows for computers to be configured automatically to communicate with each other over an IP network without the need for manual setup by a network administrator.

The implementation of DHCP relies on a DHCP server to hand out network configuration information to DHCP-capable clients that request an IP address (and other information required or useful in communicating with other devices on an IP network). In addition to an IP address, common configuration information served over DHCP includes a default gateway, subnet mask and DNS sever(s), though there are many more possible configurations that can be sent out using the DHCP protocol.

More in-depth detail on DHCP and its implementation can be found at Wikipedia.

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Why does it take seconds to obtain IP address via DHCP?

Out of curiosity, why does it often take seconds to obtain network configuration via DHCP when the CPU is capable of processing millions of operations per second and ping to the router takes a couple of milliseconds? In my home environment with one…
Borek Bernard
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What is a good DHCP lease timeout configuration

I have generally seen that DHCP lease times are quite long (a day plus) on most defaults. I have a client that seems to have the following problem. They have a DHCP server in a router that is near-saturation (say in a normal work day 80-85% of the…
Yishai
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Can a DHCP server assign itself an IP address via DHCP

This may seem a daft question (and i fear it might be), but would it be possible for a server acting as a network's sole DHCP server send out a request for an IP address to the network, then catch its own request and answer it? All of my intuition…
James Butler
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Static IP, but DNS and other settings from DHCP

The IT guy gave me an IP address outside of the DHCP dynamic pool range (I do not have a DHCP reservation). I'd like to set linux client's IP staticly, but still have it pull the DNS servers and domain name from DHCP. Searches have only turned up…
Codebling
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What is DHCP Rebinding?

My external network interface on a gentoo box will produce these errors intermittently (maybe 3-4 a week). It is hooked up to Optimum online, and gets its IP via DHCP. It's always-on, and it almost never loses connection (when it does usually I or…
Tom Ritter
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What do DHCP Lease Time and Domain Name do?

Why do we need to set a lease time to a DHCP server? What happens to a client who uses that IP address while it was expired? If i set its time to 100 years, what difference does it make? Also, i don't know why we have to set a domain name to a DHCP…
platypus
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Static to DHCP, bat file

I have this code (.bat file) that I want to run by going to each computer that is logged in and executing it. However, not all users have admin rights. Is there anything I can do without logging off to change the IP's from static to DHCP? netsh…
Markaway
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How can I assign DHCP leases from a script?

I have an environment where there is one DHCP server servicing a number of different hosts/vlans. The switches are configured to forward the DHCP requests over (via ip-helper) and include information about the port (option 82). I'd like to take…
devicenull
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DHCP server identifier and DHCP relay

I have a DHCP server serving a number of subnets over a DHCP relay. When it sends out DHCP offers it sets the server identifier (option 54) to its own IP address. When the clients need to renew they try to unicast to that IP address, which none of…
mmb
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DHCP Server Slow to give out IPs

My Windows 2003 server standard DHCP server takes 30-45 seconds to give out an IP to XP clients. I've never seen one this slow before. The server is not overwhelmed. We are on 100 Mbps switches. Any ideas or suggestions?
Nate
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DHCP server doesn't receive DHCPREQUEST packet sent by client

DHCP packet between hosts gets lost. The server sends DHCPOFFER to client. Client gets DHCPOFFER from server. Client sends back DHCPREQUEST. Server does not receive the DHCPREQUEST packet. Can anyone suggest what could be the reason for this?
sara
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DHCP reservations for same IP on first come, first serve, basis?

Here's the scenario: I have a main server and a backup server park. Due to the setup, there are port forwards active on my router to one specific ip address. Of course, I could make reservations for the backup server park too, but that would mean…
LPChip
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How do I prevent other unwanted DHCP servers?

I have a network with a DHCP server and RADIUS authentication. Clients connect to my network, get a DHCP address, enter the signing in page, input their prepaid cards, and get to the Internet. We sometimes see some clients (was once malicious)…
Questioner
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DHCP Discovery being Ignored

I'm having some real issues with a DHCP server I've setup. I'm at my wit's end, having found no answer anywhere to this problem of mine. Here's the setup: I have a CentOS server machine, running ISC's DHCP server. This machine has two interfaces…
Lopson
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Determine when changed from static to dhcp?

We have a machine running Windows Server 2012 that is using DHCP for ip assignment, in an Active Directory network. It is standard protocol for us to use static ip and no one recalls changing this machine. Is there a way to determine when the LAN…
matt wilkie
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