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

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43
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2answers
147k views

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 ...
62
votes
11answers
156k views

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, ...
12
votes
1answer
7k views

How to request dhcp (using dhclient) on a virtual interface (i.e. eth0:1)

This seems to work fine: dhclient eth0 ifconfig eth0:1 192.168.1.105 up But not this: ifconfig eth0 192.168.1.105 up dhclient eth0:1 Is there any way to get dhcp on a virtual address?
11
votes
4answers
15k views

Register A records for my Linux box on my Windows 2008 DNS/DHCP server

I've a network which is mainly Windows: Windows 2008 server (with DNS/DHCP as well as AD), and various mainly Windows machines (servers, XP, 7). I know trying to add few Linux boxes, and can't make ...
4
votes
2answers
383 views

How do I force all devices on a network to register with IT before connecting, without vulnerability to Static IP-ing or MAC spoofing?

Context: I'm an admin for a midsize corporate network with several overlapping wireless access points and an ethernet cabling infrastructure. To comply with a security audit, we were recently ordered ...
3
votes
2answers
2k views

Reserve a single ip for a wired and wireless NIC of the same machine

I'm using w2k3 dhcp server, and I've reserved an IP adress for my laptop to facilitate port forwarding. I previously had a pure wired network, but I just added a WiFi router to this network for the ...
2
votes
2answers
5k views

Redirect all DNS-Requests with dnsmasq

I have following scenario: I have set up an ad-hoc network with wicd on my server, and use dnsmasq as an dhcp- and dns-server. The network works very well, I can connect, get an ip address, and on all ...
8
votes
2answers
7k views

IPv6 DHCP Configuration

I want to set up an IPv6 only network for testing. However, I can't find any HOWTOs or information on setting up DHCP to autoconfigure IPv6 DNS server addresses etc. I use radvd on a ubuntu server to ...
23
votes
4answers
1k views

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 ...
8
votes
5answers
13k views

Reverse DNS records not registered when using DHCP

I've stumbled upon a strange behaviour with Windows machines, which seems to be fairly consistent between all Windows versions from Vista/2008 to 8.1/2012 R2; it doesn't happen instead when using ...
2
votes
1answer
6k views

How to ignore a set of Mac addresses in dhcpd.conf?

Is it possible in dhcpd.conf to ignore requests from a set of MAC addresses? Something like this: host vminstances { hardware ethernet d0:0d:*; ignore booting; }
11
votes
1answer
27k views

VLAN tags not shown in packet capture (Linux) via tcpdump

I am adding a tagged VLAN onto eth0: #ip link add link eth0 name eth0.20 type vlan id 20 This results in: #ip link 2: eth0: <BROADCAST,MULTICAST,PROMISC,UP,LOWER_UP> mtu 1500 qdisc ...
4
votes
1answer
1k views

Assign DHCP IPs for specific MAC prefixes on Windows Server 2008 R2

I'm running Windows Server 2008 R2 for my DHCP server. We are about to switch over to a VoIP system and Cisco VoIP phones. I would like to assign a specific range of IPs to these phones which will ...
3
votes
2answers
5k views

How do I dynamically obtain IP addresses for VLAN interfaces?

I have an Ubuntu machine on which I have created four VLANs, namely eth0.100 ,eth0.200 , eth0.300 and eth0.400. I want to dynamically obtain the IP addresses using the DHCP server. It should provide ...
2
votes
1answer
46k views

Event ID 4013: “The DNS server is waiting for Active Directory Domain Services (AD DS) to signal…"

We have an issue that only occurs after we rebooting our secondary DC and DNS server/DHCP server. It is a 2008r2 x64 server, DC and DNS/DHCP server. Our main DC is 2003. Event ID 4013: “The ...
0
votes
2answers
2k views

Linux DNS Client Update Tool

So I work in a web hosting environment, and I've got a handful of Linux boxen on our primarily Windows-based network. All the machines (both Windows and Linux) on the network have at least two ...
2
votes
1answer
193 views

DHCP IPV6 Environment

May I know what are the changes needed in the DHCP message formats if I want to convert into ipv6 environment? Now I am using ipv4 dhcp client and ipv4 dhcp server. But I want to implement this using ...
1
vote
4answers
205 views

Does DHCP protocol allow a server to offer multiple addresses to clients instead of just one? [closed]

This is an exam question of Internet Protocol. I thought the answer is "NO" but I want to make sure.
0
votes
5answers
901 views

Will a router allow network traffic from a static IP?

We have some servers in a data center but the data center does not offer a DHCP service. We want to have some computers setup with DHCP and others that have static IP's. Currently our WAN cable going ...
-1
votes
1answer
204 views

What's the design rationale behind DHCP requiring two phase exchange, DHCPDISCOVER then DHCPREQUEST [closed]

RFC2131 section 3.1 describe the DHCP working flow as follows: Server Client Server (not selected) (selected) v v ...
12
votes
3answers
13k views

Howto setup Cobbler with PXE if you can't change the dhcp server?

In the past I've setup a PXE server several times by making the normal dhcp server return everything needed for network booting: both the regular ip config AND bootinfo in a single dhcp setup. That ...
20
votes
4answers
25k views

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 ...
27
votes
5answers
4k views

Locate rogue DHCP server [duplicate]

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 ...
14
votes
4answers
4k views

Windows DHCP Server - get notification when a non-AD joined device gets an IP address

SCENARIO To simplify this down to it's easiest example: I have a Windows 2008 R2 standard DC with the DHCP server role. It hands out IPs via various IPv4 scopes, no problem there. WHAT I'D LIKE I ...
12
votes
1answer
2k views

How to set up Google ShortName service for my domain, so that the FQDN isn't needed

The blog post "A 'tinyurl' service for your domain" explains how to set up a ShortName service for your domain using Google Apps. For example, if your domain is example.com and you use Google Apps, ...
12
votes
5answers
14k views

Why can Windows machines resolve local names when Linux can't?

I have a small network with Windows and Linux machines connected to a D-Link DIR-825 router. The Windows machines on the network can reach all other machines by name while the Linux machines only can ...
12
votes
2answers
9k views

PXE Booting Virtualbox guests in internal networking mode?

I am not sure if this is just specific to my distro's packages or is a vbox limitation. So, any help would be appreciated. Ok, so I have a network of VMs, with one VM acting as a NAT for the other ...
5
votes
5answers
10k views

Override DHCP hostname on RHEL5/CentOS/Amazon Linux

I'm running Amazon Linux (based on RHEL5) on EC2. I have my own domain name pointing to the instance's elastic IP. Amazon auto-assigns the instance a generic (and not visible on the Internet) ...
3
votes
4answers
12k views

Split your DHCP scope among multiple servers?

I want to implement a redundancy solution. I have two subnets all windows XP machines - each with their own DHCP server - joined by a bridge. Currently - all machines get DHCP leases from the one ...
11
votes
2answers
30k views

Multiple VLANs, multiple subnets, single DHCP server?

At my job we are prepping to transition from multiple LANs connected over slow VPN connections to a single MAN connected over fiber, and I've got a few questions. First of all, we are planning on ...
4
votes
4answers
11k views

Debian interfaces file - ignore gateway and dns entries from dhcp

In gentoo, this is as simple as: dhcp_ethX="nodns nogateway" How should I go about this in the interfaces file?
17
votes
4answers
36k views

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?
10
votes
1answer
6k views

Is there a downside to always updating DNS from DHCP?

I've got a Windows 2012 Domain Controller running DNS and DHCP servers. The default setting appears to be Dynamically update DNS A and PTR records only if requested by the DHCP clients. (This is ...
6
votes
7answers
4k views

Static IP Address assignment vs DHCP address assignment

I manage a small-ish network that consists of less than 70 nodes. The previous system administrators opted to have a dhcp server and manually set dhcp addess. I have opted to rather use dhcp ...
5
votes
5answers
19k views

Which DHCP Client OS Support DHCP Option 119 Domain Suffix Search?

The ability for DHCP servers (Microsoft, ISC, VitalQIP, IPControl, Infoblox, etc.) to deliver DHCP Option 119 - Domain Suffix Search Lists has been around for a long time. Initially, DHCP Client ...
3
votes
3answers
5k views

Clonezilla-SE with another DHCP Server in LAN

I want to install Clonezilla-Server(192.168.1.100) in a network that already have a DHCP Server (dd-wrt with dnsmasq - 192.168.1.1). I've installed Clonezilla-SE on ubuntu Server 10.10, once installed ...
2
votes
5answers
45k views

How to extend IP Range from 192.168.1.1 to 192.168.2.254

Here's my question. I currently have a network setup to have Static IP manually assigned between 192.168.1.1 and 192.168.1.99 and the rest (192.168.1.100 through 192.168.1.254) assigned automatically ...
8
votes
4answers
3k views

DHCP on-the-fly block assignment

We have a large number of clients who connect to our DHCP machine. We want to assign some of them to a different IP block, which is routed with lower priority. Every DHCP lease renewal, we'd like to ...
6
votes
1answer
7k views

Why would Windows Server not respond to DHCP DISCOVER?

My network was working just fine and I broke it. There is a Cisco 1711 router which was configured to hand out DHCP leases to the client PCs. I have a domain controller (Server 2008) on the same ...
4
votes
1answer
780 views

Request multiple IP-addresses via DHCP on a single physical interface (OpenBSD)

On OpenBSD, is it possible to request multiple IP-addresses via DHCP on a single physical interface? It looks like DHCP leased addresses can't be assigned as aliases. I though of creating a virtual ...
4
votes
2answers
29k views

How does 3G/Mobile phones get allocated an IP address? Does this mess with Google Analytics? [duplicate]

This question is in two parts. Q1. How does a mobile phone get an IP address over 3G? Like, would it get the same IP for a shortish period of time (Eg. 1 day, etc)? Because my phone is constantly ...
3
votes
1answer
3k views

DHCP reply packets do not make it into KVM instance in OpenStack

I'm running a KVM instance inside of OpenStack, and it isn't getting an IP address from the DHCP server. Using tcpdump, I can see the request and reply packets on vnet0 of the compute host: # ...
3
votes
1answer
11k views

Fixed and dynamic IPs in ISC DHPD lead to double lease

I would like to have a small dynamic adress part and the most clients are assigned a fixed IP adress. My dhcpd.conf looks like this: use-host-decl-names on; authoritative; allow client-updates; ...
3
votes
2answers
4k views

How to use auto-discovery with iDRAC Enterprise?

All I want to do is: have "auto discovery" enabled on my iDRAC enterprise at the factory rack the server, cable iDRAC to dhcp-enabled management network have the iDRAC DHCP, find the "Provisioning ...
3
votes
5answers
4k views

Having a domain controller on the same network as a wireless router

I have a win server 2k3 machine as a domain controller and a dhcp server. All of the wired machines work fine connecting to the domain controller and authenticating but the users that connect to the ...
2
votes
2answers
7k views

Why won't dhclient use the static IP I'm telling it to request?

Here's my /etc/dhcp3/dhclient.conf: request subnet-mask, broadcast-address, time-offset, routers, domain-name, domain-name-servers, domain-search, host-name, netbios-name-servers, ...
2
votes
1answer
8k views

DHCP not actually updating DNS even though logs indicate otherwise

This question is sort of a follow-up to this previous question: http://serverfault.com/questions/34553/dhcp-failing-to-update-dns We have a Windows Server 2003 SP2 machine that is a domain ...
11
votes
9answers
83k views

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 ...
6
votes
4answers
4k views

Force Linux servers to automatically try to get an IP address if they lose it

We use static DHCP leases for our Linux servers on our small business network. Recently something bad happened to the DHCP server and all the linux servers ended up losing their IP addresses since ...
5
votes
2answers
3k views

Need help understanding Windows DNS, DHCP and dynamic PTRs

I have inherited management of a set of AD servers running AD-backed DNS. One of them is running DHCP. For IP ranges which are served by this Windows DHCP server, the in-addr.arpa zones are being ...