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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DHCP Trouble; getting APIPA addresses

I am having trouble with the DHCP Client. I am using a Netgear fvs336gv2 firewall. I recently upgraded to the new firmware and did a factory default reset and reconfigured all the vpn tunnels and LAN. ...
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2answers
1k views

Domain Controller offline for a few days

My primary domain controller died over the weekend, its motherboard is being replaced tomorrow. I have been told that the mac address of the server may change once the new motherboard is installed. ...
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1answer
120 views

DHCP on main interface (eth1) and static on eth1:0

So the configuration is a bit weird, from our internet provider we get an IP via DHCP, there's also a whole subnet that's routed to this IP. I solved it by adding a second interface with the static ...
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1answer
60 views

incorrent subnet/mask combination

For a network interface, I have defined a range of addresses for DHCP. 3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UNKNOWN qlen 1000 link/ether 08:00:27:5a:3e:be ...
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45 views

force dhcp server to always run

I have an Ubuntu machine with two Ethernet network interfaces and on one of them I am running a DHCP server (isc-dhcp-server). I noticed that the server daemon stops running whenever I suspend the ...
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797 views

DHCP_HOSTNAME isn't working consistently in RedHat 7

Under RedHat/Centos 6.x I used DHCP_HOSTNAME=`hostname -s` in /etc/sysconfig/network-scripts/ifcfg-eth0 to pass client hostname to DHCP for registration in DNS and this worked flawlessly. I'm now ...
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1answer
162 views

Query DHCP with mac address

I am trying to create a dynamic IP resolver using python3 on linux to query a windows DHCP server and return the IP that it would be given. My purpose is to supply the returned IP address as a ...
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2answers
1k views

Gateway gets stripped from DHCP Reply through OpenVPN tunnel

I have a bridged OpenVPN setup. This is my server config: port 1194 proto udp dev tap0 ca /etc/openvpn/easy-rsa/keys/ca.crt cert /etc/openvpn/easy-rsa/keys/server.crt key ...
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1answer
244 views

Cisco AP vlan setup

I have been racking my brain since last night and all morning with this problem...luckily it's not in a production environment yet. I have done many searches and have come up with the same responses ...
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1answer
253 views

Configure OpenNebula to use DHCP

I'm trying to configure OpenNebula to use the DHCP server that already exists on my network. Yes, I already know that OpenNebula manages virtual mac addresses rather than IP addresses, but that ...
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1answer
84 views

Is it possible to add a description on a Windows DHCP Server exclusion range?

Is there way to set a description on an exclusion range within the DHCP server in Windows Server 2012, beyond the default of "IP addresses excluded from distribution"?
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2answers
536 views

DHCP failover didn't work when one server was offline

I'm running two DHCP servers both with Windows Server 2012. They are set up as with high availability using "load balanced, split 50/50." They named DC1 and DC2. This morning, DC1 was frozen, there ...
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2answers
63 views

Can I configure a connection a network with a gateway with a static ip to a network where the gateway address is assigned via dhcp?

I have two networks with each gateway on a separate network device on a single computer. One is a static ip network on the ethernet device, the other is a wifi connection to a router that is assigning ...
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1answer
39 views

Windows DHCP MAC-Range to Scope allocation

I wonder if there is any options to map a specific Range of MAC addresses to a specific DHCP address scope. The thing is, I want a specific scope for address allocation to bridged Virtual Machines ...
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120 views

ISC DHCP Server - Client Uplink Is Not Working

Running a DHCP server, client(s) does not have up-link (0Mbps) and has a downlink (50Mbps.) I am setting up a gateway/router on a PC running Debian Wheezy with ISC-DHCP. I have 1 WAN (eth0) and 2 LAN ...
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273 views

OpenVPN Linux Client does not bring up tap0 interface

I have an OpenVPN client on Linux connecting to an OpenVPN server. The server assigns IPs via DHCP, thus I connect using the tap interface rather than the tun interface. OpenVPN connects, ...
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230 views

Issuing 'ip dhcp relay information trusted' command on a VLAN interface

I was reading this article - Allowing option 82 in Cisco DHCP relay agents. It says As a security measure, Cisco IOS will not forward DHCP requests that contain Option 82 information and a ...
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331 views

Windows Server 2012 DHCP and OSX Devices

I've recently put together a small office network (around 20 devices) with an attached machine running Windows Server 2012. Our gateway router provided by our ISP was pretty useless and started ...
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364 views

Windows 7 Pro - DNS Servers changed on DHCP-enabled workstations over weekend, not sure how

This morning I came in to our SOHO office (>5 users) to reports of the internet not working. I tried all the usual simple fixes like cycling switches (each user has a switch at their desk) then I ...
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92 views

Binding ISC DHCPD to a virtual (heartbeat) interface

I had a DHCP server that acted as a relay endpoint and worked fine. let's say this is a solo machine with eth0 with an ip of 192.168.0.10 I needed to bring this server down and join it to a cluster, ...
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2answers
159 views

Rotating DNS servers specified by DHCP

I've got an OpenStack cluster running with about 200 CentOS instances and I've gotten a complaint from my hosting provider that the DNS traffic is getting to be too much for their servers. To address ...
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2answers
142 views

Unable to locate DHCP Server …

I am supporting a mixed Mac OSX and Windows environment. There is a rogue DHCP Server which seems to be providing the ip-addresses to Mac systems on the network. I have used both ZenMap and Wireshark ...
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1answer
82 views

DHCP server hardware [closed]

I have a user who needs to set up a DHCP Server for about 8000 users. Can I set it up on regular PC hardware. So far we have not set it up for more than 200-300 users. Are there anything which I need ...
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4answers
120 views

How does a host receive an IP if there's no DHCP server? [closed]

If a new host connects to a LAN without a DHCP server, how does it receive an IP?
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4k views

Issue with RHEL7 and disabling NetworkManager

Okay community, let's see if we can figure this one out, cause I'm out of answers. Where I work I am setting up a bunch of RedHat Enterprise Linux servers. There is a collection of RHEL6 and RHEL7 ...
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1answer
100 views

How can my server announce its presence to everyone in the network [closed]

The situation is as follows. I want to have an application running on a server. All of the desktops in the company has to connect to it. But I do not want the IP address of the server to be hard coded ...
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288 views

Advanced DHCP configuration (isc-dhcp-server)

We are managing our network by using DHCP and we sometimes add new subnets (IP Pools) to network through different VLANs. What we want to do is to manage all those IP pools from same DHCP server but ...
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2answers
330 views

Sonicwall SSO with NPS

I have a SonicWall where I want to enable the RADIUS SSO capability. The article for doing this states the RADIUS server Send the user’s IP address in either Framed-IP-Address or Calling-Station-Id ...
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69 views

DHCP User Class ID Notation (numerical vs. ASCII)

Creating a new DHCP User Class (on Windows Server 2008 (R1) 32-Bit) on can set a "Display Name" – here SuperDuperClass – and define the User Class ID numerically (1st & 2nd column) or ...
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1answer
115 views

cmd: create dhcp superscope

On Windows Server 2008 (R1, 32-Bit) I've got that far to create a superscope on the command line via cmd, not PowerShell (yay!) through netsh dhcp server \\SERVER scope IP.ADD.RE.SS set superscope ...
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3k views

Samba4 Internal DNS with DHCP Server

On FreeBSD we run Samba4 as a DC and until recently had our IP addresses handed out by the routers DHCP server. We switched to running a DHCP server on the FreeBSD machine with the following ...
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1answer
665 views

Server is assigned IP by GUID rather than MAC address in DHCP

I recently installed 8 new Dell PowerEdge c6220 II servers with dual 10G ports with CentOS 6. Each server has a DHCP reservation configured from a Microsoft 2003 DHCP server. I am using a Bootutil ...
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143 views

Clients do not see DHCP Server… what am I missing?

Old router died and just got the new one in and I can't figure out what I'm missing to forward dhcp and dns to windows server 2012. Old router was a netgear R6300, new one is an N900. Before the ...
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1answer
167 views

Configure and monitor Windows 2012 DHCP server with Powershell

We've recently been working with the documentation here to set up some access policies for a new DHCP server. I've been able to successfully import 600+ records with the Set-DhcpServerv4Policy -Name ...
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1answer
129 views

Static DHCP binding

Good time of day, SF people. I have created a manual DHCP binding entry on a Cisco router so that a client would always get leased to it. The clients wants to get the same address on both of his ...
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1answer
230 views

keepalived vip removed with dhcp renewal

I am having this strange issue where my vip is being removed from my interface when I receive a new DHCP renewal request. The logs shows the following: Jun 1 17:00:06 lb1 dhclient: DHCPREQUEST of ...
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1answer
748 views

On Windows 2008 R2, how do I back up DHCP if the DHCP .mdb database is always busy?

I get this from my backup software. C:\WINDOWS\system32\dhcp\dhcp.mdb : The process cannot access the file because it is being used by another process. C:\WINDOWS\system32\dhcp\j50.log : The ...
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1answer
9k views

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. ...
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576 views

DHCP offer is unicast but DHCPACK is broadcast

My DHCP server broadcast DHCPACK 0xffffffff . it is not working on layer 3 dhcp relay agent . as it can not forward this broadcast message to my client. can any one help me from exactly the broadcast ...
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1answer
157 views

CentOS 6 DHCP server configuration

I have a CentOS 6 server running on a virtual host. The IP address on this host get assigned through DHCP host and another interface has an static IP ( a test network). I want to setup an private DHCP ...
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2answers
789 views

Assign fixed IP address via DHCP by DNS lookup

Preface I'm building a virtualization environment with Ubuntu 14.04 and LXC. I don't want to write my own template since the upgrade from 12.04 to 14.04 has shown that backwards compatibility is not ...
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3answers
2k views

Superscope DHCP leases and configuration set up

Hello I wanted to see if someone could help with a network problem I am having. Right now we have a super-scope and scopes of 192.168.50.1 and 192.168.51.1, as of now both are activated but only ...
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1answer
1k views

How to statically configure DNS servers on a Cisco router when the WAN interface uses DHCP?

I have a Cisco router (model 887VA, IOS 15.4) used to connect a LAN to the Internet via ADSL. The WAN interface uses DHCP: interface ATM0.1 point-to-point ip address dhcp I need the router to use ...
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1answer
92 views

Routing DHCP traffic over the internet

i'd like to know if it's possible for the internet to be between a DHCP server and the network it's "assigned" to? so basically, something like this: -------------- ------------- ...
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1answer
154 views

Is there a way to use Bind9 $GENERATE directive for rDNS of ranges bigger than /24?

The $GENERATE directive of bind9 makes it possible to autogenerate the reverse mapping for a range of IPs what is really helpfull for reverse dns of a dhcp range. But it seems that the $GENERATE ...
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32 views

failing to configure a dhcp scope under Oracle Virtualbox

I've got a problem configuring a link between WS 2008 and Windows 7 both running as virtual machines (under Oracle VM 4.2.something). Static addresses do well, with both ping 192.168.1.2 (client) and ...
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191 views

pfSense + Squid, Windows 2008 DHCP

I recently installed pfSense and Squid3-dev on a spare machine. It is now connected to the network and Internet is working alright. The problem is that I can't get my users to go through Squid proxy ...
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221 views

ISC DHCP Option 82 binary-to-ascii for host declaration

If the relay agent encodes the option 82 as binary data (as is the case with Cisco and Brocade systems, at least), How can one perform this match: host 10-24-24-9 { host-identifier option ...
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1answer
1k views

dnsmasq(as DHCP server) isn't working in KVM+libvirt envirmont

I'm using dnsmasq as DHCP server in VM environment. But It didn't working. I disabled basic DHCP feature in libvirt. <network> <name>default</name> ...
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1answer
239 views

Forwarding DHCPOFFER through bridged OpenVPN

Setup: host <---> OpenVPN-client with DHCP-helper <---> OpenVPN-server <---> DHCP-Server Except "host" everything is setup with static IP's and routing works fine. All stations can ping ...