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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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Can I have multiple DHCP servers on one network?

This is a Canonical Question about Redundant DHCP Servers. Is it possible to have more than one DHCP server on the same LAN? What are the implications of doing this? What happens if there is more than one DHCP server available? How do my clients…
Rob Moir
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How do I find if there is a rogue DHCP server on my Network?

What's the best approach towards determining if I have a rogue DHCP server inside my network? I'm wondering how most admins approach these kinds of problems. I found DHCP Probe through searching, and thought about trying it out. Has anyone had…
l0c0b0x
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Command line program to test DHCP service

Is there a simple ping-like command to test whether a DHCP service is running on a network? ...on Linux
pufferfish
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How do I force Linux to reacquire a new IP address from the DHCP server?

The environment is Debian, although the answer will apply to all distributions.
GeneQ
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KVM/libvirt: How to configure static guest IP addresses on the virtualisation host

What I'd like to do is to set the guests' network configuration (IP address, subnet, gateway, broadcast address) from the host system. The used network setup is in bridge mode. How can I configure the network from the host rather than configuring…
beta
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How do I request a new IP address from my DHCP server using Ubuntu Server?

I know there is a simple command for this, but how do I tell my Ubuntu server instance to request a new IP address from the DHCP server on eth0?
Heat Miser
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dhclient: What does "RTNETLINK answers: File exists" Mean?

I wanted to update the DHCP lease of an Amazon EC2 instance, so I executed the following command: user@host:~$ sudo dhclient Following that, the system's DHCP lease is updated successfully updated. However, the command prints the following to the…
AlfaZulu
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Any way to find unused IP addresses on my network?

How can I locate unused IP addresses on my network? The DHCP server keeps assigning the same address and I need a different IP address to test my application with. The software would need to run on Windows.
jasonh
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How do you get dnsmasq to specify alternate DNS servers?

I'm working on a network with ~10 kubuntu desktops (and numerous servers and IP phones) and am trying to get dnsmasq to specify another dns server as a failover. I tried using server=192.168.0.90 but that just added the single dhcp/dns server to…
pfyon
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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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How does a computer obtain an IP address via DHCP?

How does the computer know which device on the network to query? How does the default gateway factor into this? Pretty much, what is the chain of events that occurs when a computer tries to obtain an IP address using DHCP? The reason I ask is…
Bigbio2002
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How do I determine what my DHCP server is?

I have a sad network left behind by some careless administrators - I am in the process of figuring out exactly what services are running where, not excluding the possibility that some services are running from two places at once, which is tons of…
Manca Weeks
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DHCP Options for Network Time Server

It looks like there are two options for providing network time settings to a DHCP client; option 004 and option 042. The description for 004 is "Time Server", while 042 specifies NTP. Is there a reason to use one or the other, or is it just vendor…
TimM
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1 Year DHCP Lease

Just a little background I'm a fairly young I.T. Tech working in a school only and only been working in the as a technician for a few years so I would still consider myself a "newbie" Anyway, My boss recently (Friday) increased our DHCP scope and…
Le_Quack
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Locate rogue DHCP server

Possible Duplicate: How do I find if there is a rogue DHCP server on my Network? I know this is a serious long shot, but here we go. In the past week or so, for users connected to a particular switch in our network (there are four dumb switches…
Mark Henderson
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