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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Windows 2012 DHCP Failover: Scope refuses failover config Error: 20044

I have a scope configured on a Windows 2012 DHCP server (primary in a hot standby config) with two Cisco Vendor class options. I've added the Vendor class options, identically, to the standby server. ...
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Setting dnsmasq_config_file with Puppet managed OpenStack installation

Our OpenStack installation is rolled out with Puppet. We use the excellent puppetlabs-openstack module for that. Due to the slow turnover cycles we are still stuck with version 5.0.2, right now we ...
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DHCP snooping on distribution layer stops cliens on access from getting ip address

Here is my topology: sw1(gi0/1 trusted port)->sw2(gi0/1 trusted port)->core-sw(gi0/1)->DHCP_server at the beginning i only configured sw1: ip dhcp snooping ip dhcp snooping vlan 18 int ...
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Interface being deleted

I have a cluster consisting of CentOS6.5 and CentOS7 virtual machines. I've come across an issue where the network interface, eth0, is being deleted for reasons unknown and I'm looking for help on how ...
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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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Why is Server 2012 assigning “169.254.*.*” series when creating DHCP server?

I have a small office, with ATT Motorola modem (192.168.1.254) set as passthrough to Dlink DIR-815 (LAN 192.168.0.1) I am trying to setup DHCP server on Server 2012, and when I create new DHCP server, ...
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How can I clear the DHCP GUI in OSX Server? Ghost clients in the building

I have a few client machines showing up in the network (not only in Server.app but also in various logs), which have "Computer Names" (Bonjour names in Apple-speak) which I don't recognize, but ...
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14 views

DHCP Relay agent not working

I'm quite new to the DHCP Relay Agent thing, but it seems to be best solution. So here is the deal: DHCP server (Win 2012R2) is at 10.0.3.1/24; ServerB (Win 2012R2) is at 10.0.3.3/24 and 10.0.2.1/24. ...
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OpenWRT Chaos Calmer 15.05 DNS forwarding, custom DNS Server, DHCP option - nothing works [closed]

Okay, so essentially I'm trying to only forward one very specific address over one of those geo unblock dns proxy services. Namely Pandora.com. Don't judge, I like their raido stations better than ...
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DHCP client not getting IPv4 address from a DHCP server

I configured a DHCP server on a VM in VirtualBox. This machine has 2 network adapters, enp0s3 - NAT (from where I have my network connection) and enp0s8 - Internal Network (intnet). DHCP server is ...
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Abnormal DHCP Android device traffic cannot be identified

Hi Serverfault community members. I've been trying to identify the source of an abnormal broadcast traffic generated by some Samsung Android devices with no success, so I ask for your help. I have ...
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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) ...
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1answer
1k views

VLAN & WiFi & DHCP with Cisco SG200

I'm trying to configure a small business network with one Cisco SG200-26, a Linux server and two TP-Link TL-WA801ND. I have set up the APs to have two different SSIDs, Public and Staff, and have ...
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26 views

Why a computer in one VLAN cannot get an IP address from a DHCP server in another VLAN?

Can anybody please explain as to why a computer in one VLAN cannot get an IP address from a DHCP server in another VLAN by default? Why is there a need for a DHCP Relay Agent or an IP helper, they all ...
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10 views

Dhcp Classless Static Routes hook error

I have a dhcp server that hands network information to vms of mine. It works fine for centos6,7 , and debian 7 clients. However it fails for Debian 8 and Ubuntu 16.04 clients. For the ones where it ...
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two domains, one LAN, two DNS server, 3 problems

Background: we have 150 users using AD on domain ABC. Windows 2003. that serverDC1 has a DNS, DHCP roles, and there is serverDC2 which is its live DNS backup. logs seem healthy. then we chose to ...
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552 views

DHCP Requests cannot get through Switch

First a little about the network setup: We are a smaller department of a larger school. We have 7 offices with TP-Link managed switches as well as 20 APs and 24 classrooms. The switches, APs and ...
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42 views

Can a computer on one VLAN acquire DHCP from another VLAN?

Can you please explain what needs to be done in order for a computer in one VLAN to get an IP from a DHCP server in another/different VLAN? (Yes if something is done and no if that something is not ...
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CentOS: DHCP Server and DHCP relay on same machine

eth0 IP: 192.168.1.100 Alias interface eth0:dhcp IP: 10.10.1.100 dhcpd.conf: authoritative; local-address 10.10.1.100; subnet 10.10.1.0 netmask 255.255.255.0 { range 10.10.1.10 10.10.1.50; ...
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33 views

DHCP renew fails with multiple subnets on same link

Our network currently consists of 3 subnets on the same link: 1.2.3.0/24 is the global subnet 10.1.0.0/16 is used for NAT (because there are far more than 200 clients) 192.168.0.0/16 is the "guest ...
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How can I block access to the internet for static addresses?

I have a router on CentOS 7 which provides access to internet for several IP addresses, which are reserved at DHCP server. Other hosts are blocked. If someone put static address from the reservation ...
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Dual-port server acting as router, but LAN can't see WAN

Using Windows Server 2012 Essentials. I've got two ethernet ports. One is connected to a router which is connected to the internet. This portion of the network is fine. The router runs DHCP on the ...
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Multiple interface Red Hat 6 ISC DHCP Server sending Incorrect PXE next-server

My setup: Red Hat 6.7 isd dhcp server 2x networks connected (A and B) One DHCP pool configured on Network A When I had this server set up on a single network ("A") it worked fine, now that I added a ...
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Retrieving kickstart and other .img file in pxe remote installation in CentOS

I am trying to installation CentOS through pxe tftp installation. Installation starts but it fails to download image files from the http server. but file are accessible on the http server. Logs from ...
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Restricting Source IP of DDNS Updates

Goal: For a non-Microsoft DHCP server to send dynamic DNS updates on behalf of non-Microsoft domain clients. Question: With a particular zone in a Microsoft DNS server configured for "Nonsecure and ...
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57 views

DHCP unable to deliver offers over routers

I have the following network: PCVLAN10 -> SWITCH_LAN1 -> ROUTER_LAN 1 -> ROUTER_LAN2 -> SWITCH_LAN2 -> DHCP(ROUTER) I have set up subinterfaces on the routers, and allowed trunking on VLAN 10 on ...
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Browser autostarts when ethernet is connected. How? [migrated]

I plugged my Windows 10 laptop into a router from our new isp. We only got the fibre, no services set up yet (The fibre can carry phones, tv and internet) Immediately when I plugged the cable in, the ...
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Juniper SSG5 DHCP IP Pool is full. Unable to offer IP address to client

hope we have some Juniper guys around, I have configured a Juniper SSG5 as our main firewall/router the DHCP server set on interface bgroup1 to have a rang from 10.10.10.76 to 10.10.10.210 All ...
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21 views

DHCP removing existing DNS records when asked for leases and none are available

I'm having a problem with my Dynamic DNS and DHCP setup where clients requesting leases when none are available causes a cascading failure where existing clients have their forward and reverse DNS ...
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60 views

How to get the connected wireless router's DHCP server not of another router's in the same network?

I have two internet connections and three separate wireless routers on the same network. The two dlink routers are serving one internet connection and the speedport the other internet connection. My ...
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PXE boot fails to get IP address via DHCP, but DHCP works when OS booted

I'm trying to PXE-boot a Cisco UCS C240 server to install a new OS over the network, but it isn't picking up an IP address via DHCP during boot. I get the "No DHCP or proxyDHCP offers were received" ...
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36 views

DHCP Configuration

Our network ran out of IP address on the current local subnet, so my boss requested our service provider to change our subnet from /24 to /20, it will give us more than enough IPs to assign to the ...
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Client see Windows Deployment Services but still get “selected boot device failed” error

Like the title says I can't Windows Deployment Services working. The client laptop has an ethernet IP address of 10.0.4.94. On the secondary DHCP server I've set option 60 to PXEClient, option 66 to ...
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How can I block all traffic to/from an bridged interface while allowing DHCP?

I have a PC (running Fedora 20) that is being used as a "software switch" to control the network connectivity of some external devices. There are eight such devices; the PC has two 4-port Ethernet ...
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DHCP Server on Windows Server 2012 Essential [on hold]

We have 250+ users with static IP's. Going to deploy DHCP server in network by looking into growing numbers of devices in near days. I have one 2012 R2 Std. box which will be primary for DHCP ...
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How can I configure systemd.network DHCP server to distribute IP routes?

From this question I understand that I can use DHCP to distribute classfull routes. How to do it with the DHCP server embedded in systemd.network (if possible)?
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Multiple DHCP uplinks - How to ignore DNS and default route on all but one?

A multi-homed box needs more than one uplink to be configured for DHCP. It needs to ignore default-route and DNS for all but one DHCP uplink. There is a similar question here [ Debian interfaces file ...
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how dhcpd handles static IPs vs DHCP reservations

We have a RHEL 6.7 server for DHCP. I am needing some clarification on how dhcpd handles network addressing when someone wants a permanent IP address. Here is a sample config from one of our servers. ...
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25 views

DNS is not enabled for Local Area Connection

On Windows Server 2008 R2, I have an error saying DNS is not enabled for Local Area Connection with a red circled "X" by the right. In DNS I have Error 4013. I have restarted the Server, the static ...
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Traffic on eth0 despite denying it with iptables

Despite having an iptables ruleset which should not allow it - DHCP is working on eth0. Given the below information can anyone give me an idea of why? tap0 is not up (not that it should make any ...
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PFsense 2.2.6 static dhcp hostname blank

We are on pfsense 2.2.6 and we enable static dhcp for each mac address on each VLAN where dhcp is enable. DHCP is working good but when I enable static dhcp and leave the hostname empty and when I ...
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473 views

Libvirt providing bootp options without being configured to do so

I have a virtual network configured in libvirt and configured to provide DHCP (via dnsmasq) but not configured to provide bootp information (see below), but when I boot an iPXE ISO and look at the ...
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Unable to access VM after DHCPACK libvirt

The installation of a particular software makes my VM lose its connectivity. The point where it hangs is 2016-04-05 16:49:11.996 | Listening on LPF/o-hm0/fa:16:3e:b2:43:4c 2016-04-05 ...
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dhcp reconfigure extension client's support

There is reconfigure extension for DHCP - RFC 3203(FORCERENEW), which also requires DHCP-auth implementation RFC 3118. Ubuntu by default is shipped with dhclient, does it support these RFC? and what ...
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Check DHCP Option content

Is it possible DHCP client check the contents of an option ? I need provisioning a Linux server with DHCP option 140 (option-140). But the server behaves as if the DHCP did not contain the ...
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Does a Windows host correctly interpret dnsmasq parameters?

I have a network of Windows 10 machines served (DNS and DHCP) by a dnsmasq instance on a Ubuntu server (Ubuntu 15.10, dnsmasq 2.75). The setup basically works (dnsmasq provides addresses and manages ...
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23 views

Identical DHCP leases, excessive dhcp traffic

Fresh install of CentOS 7, removed dnsmasq, installed dhcp server, iptables, webmin, apache. This is school and lot of switches and wifi (bridge mode) AP's connected to this router One network - ...
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46 views

Best way to connect dual SSID / VLAN wireless to Watchguard firewall

I'm currently sorting out our network so we can have new wireless access points with dual SSIDs, one for internal use and one for guest use. These will be setup so each SSID is on a different VLAN. ...
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Debian 8 resolv.conf overwritten by IPv6 autoconfiguration/DHCP when DHCP disabled

I have recently installed Debian 8 on a network with IPv6 DHCP Enabled. /etc/resolv.conf is being overwritten by the IPv6 DHCP entires continually despite the fact that all IPv6 DHCP is disabled, ...
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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 ...