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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Misunderstanding of DHCP/DNS - What is the IP of a machine before DHCPOFFER/DHCPREQUEST

From what little I understand, DHCP allows for dynamic assignment of IP addresses to client machines on a network from a DHCP server. The client transmits a DHCPDISCOVER packet, followed by a ...
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63 views

Using Microsoft DHCP with Linux PXE/TFTP/kickstart

I have a microsoft dhcp server already in the network and i have linux servers for pxe/tftp/kickstart. I would think that it would work using a ms dchp server with pxe/tftp on linux but im not sure, ...
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1answer
713 views

Use Framed-IP-Address RADIUS attribute for IP allocation with DHCP on Windows Server 2012R2

I have configured a DHCP server on Windows Server with an NPS Policy, connected to a FreeRADIUS2 server running on pfSense. Authentication is based on MAC address. If MAC address is not present in ...
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1answer
305 views

DHCP Server Not Registering PTR Records

I've got a DHCP server that's configured to "Always dynamically update DNS records". Unfortunately, it's not doing its job. The client sends an Option 81 with its FQDN and all flags at 0. The ACK back ...
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1answer
66 views

Linux Server Update Windows Server DNS (DHCP Not Windows)

I have Linux machines that are DHCP clients that have send hostname enabled but are not updating DNS on the Windows servers. DHCP is coming from the firewall, NOT Windows. Other windows machines ...
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1answer
142 views

Internet bandwidth split with HP1810-8G, using “DSCP QoS policies” and VLANs

I have the following scenario: We are a small company (~10 clients) with little resources and we rented out office space to another company(<5 clients). We ordered a 20 Mbit fiber connection which ...
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1answer
101 views

DHCP with fixed IP hosts (Ubuntu)

I'm managing an office system that assigns IPs based on the MAC address. The fixed hosts are added in a dhcpd-hosts.conf file which is included in dhcpd.conf. There are some PCs that are not in the ...
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2answers
427 views

DHCP server on subinterfaces

I have created two subinterfaces on eth0 : eth0:0 with IP 192.168.10.1/24 eth0:1 with IP 192.168.11.1/24 Configured /etc/dhcp/dhcpd.conf like that: option domain-name-server 194.204.159.1; ...
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1answer
217 views

lan to wan connection refused by windows firewall

I have plenty of experience with LAN's and bridges however this is my first time using a WAN style setup... here is a diagram of my network WAN (public ip & 10.1.10.1)---COMP1 (10.1.10.2) ...
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1answer
64 views

DHCP Config for Server 2012 R2

This question may have been covered before, but it is rather complex and haven't found a similar post, so please be kind! I think my issue is rather unique, so I'll try to explain as best I can. I'm ...
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0answers
134 views

DHCP Failover works but no DNS available

I have a DHCP failover (load balance) configured. DHCP failover works but the clients are not getting any DNS entries. We have 2 DNS servers using AD-integrated zones, and the failover is between ...
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3answers
105 views

Can the firewall prevent the DHCP to give an address, how to fix this?

I am not getting an IP in the subnet 10.0.0.0/24 where the DHCP is working and should serve an IP, I am getting instead only an IP in the subnet 169.254.0.0/16(link local address) that is probably ...
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0answers
89 views

DHCP, IP conflict on LAN (pfsense)

On my router I occasinally get a log with multible entries like this. It is a LAN with DHCP so I guess here should be no conflict at all... Is there a nature to this? May 11 09:24:36 220002 ...
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1answer
81 views

Reaching out DHCP relayed hosts

I have one primary server (DHCP) and one secondary (DHCP-RELAY). Majority of hosts are served from primary (wirelessly), however there are a few (wired ones) which get their IPs from secondary. ...
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379 views

Configure WiFi and LAN network to use the same Kerio DHCP server

We have a local network in the company: An Ubuntu server hosted for VPS. Kerio Control Appliance 8.5 installed on VPS as internet & DHCP server . WiFi modem connected to eth0 of Kerio. eth1 of ...
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74 views

Virtualbox vm lstp client login blank for lstp server on ubuntu 14.04 , what I'm missing here..?

I am trying to configure a lstp server ( ip of lstp server : 172.16.40.0 ) on a 64bit ubuntu 14.04 and check it network booting virtualbox vm (harddisk less vm) I configured everything according to ...
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1answer
89 views

Is it possible to bring down a network with DHCP discover?

When a DHCP server receives a DHCP discover message it broadcasts the offer across the entire network. If a malicious machine joined a network and somehow began spamming DHCP discover messages, would ...
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0answers
196 views

How to configure DHCPv6 and DNSv6 configuration in Ubuntu 12.04?

I'm planning to configure DHCPv6 and DNS server in my network. I would like to understand whether both DHCPv4 and DHCPv6 can be configured using isc-dhcp-server service? When i tried nslookup ...
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0answers
113 views

How to set up a simple Cisco ISG config for controlling internet access

First off, here is my config so far. http://pastebin.com/fV2NGCE2 I've gone through a few guides online and the 15.2s manual and the xe3 manual for Cisco's ISG (intelligent services gateway) and ...
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1answer
167 views

How to move company voip phones to a different subnet by modifying DHCP of a Cisco Switch?

Our company has replaced its old voip phones with new ones which are the NEC phones. We are done with the configuration part, and the phones are working fine. But I want the phones to be in a ...
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1answer
61 views

Why does starting openvpn client, then dhcpcd give different routing table than the reverse order? [closed]

I am connecting through a router in my home, and tunneling all traffic via openvpn through a remote server. When I first connect with dhcpcd, then start openvpn, my routes look like this (on a linux ...
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1answer
150 views

Installing a new domain server on a small network without taking down the old one

I'm attempting to replace a windows server 2003 domain controller/dns/dhcp server on a small business network with a new machine running server 2012 without having to take down the old one until ...
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1answer
561 views

How to get the DHCP-controlled DNS domain name for my Ubuntu machines in a Windows network?

I've been going in circles for a while trying to figure this out. I have a number of Ubuntu machines (some virtual) on a Windows network. From a Windows machine, I can ping or nslookup the Ubuntu ...
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39 views

DHCP export using netsh

I'm trying to export a DHCP database using the following command: netsh dhcp server export c:\dhcpdb.dat all However it completes with the error WARNING: Could not obtain host information from ...
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1answer
130 views

Custom Live Boot PXE ISO Script

Currently I am using an open source PC auditing software called Open-Audit to audit PCs my company receives off lease from school districts. The software uses snmap to pull hardware information over a ...
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1answer
216 views

How to configure DHCPD server to bind static IPv6 address by DUID?

how can i configure the server to make static record DUID - IPv6 ? For example i have such DHCPv6 request: Client Identifier Option: Client Identifier (1) Length: 7 Value: 31303030303133 ...
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1answer
60 views

Cisco Router DHCP Error Logging

I am troubleshooting an issue where a DHCP client is not receiving an address during PXE boot, but receives an address with no issues once booted into Windows. Our Cisco router is also our DHCP ...
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0answers
32 views

Unique record per ip address on Windows DNS

I have a little problem with my DNS server under Windows domain. My DNS server gets automatic registration from clients by dhcp. Please consider this situation: Computer PC01 with dhcp address ...
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2answers
286 views

Automatic DNS registration only for domain computer

I have a windows domain with a win server 2012 domain controller with dns service installed. In the DNS server there is the automatic DNS registration, is it possible to limit these registration only ...
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1answer
994 views

How to implement DHCP, DNS, hostnames on AWS VPC

This is what I THINK can happen and what I want. I create a VPC in Amazon, put a public subnet into it, put a puppet server instance and a full stack web server instance in the VPC. Now I set the ...
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227 views

Create IPv4 reservation with DUID in Windows Server 2012 DHCP

Can I configure reservations for IPv4 addresses in Windows Server 2012 DHCP for systems which send DHCP requests with a DUID for their client identifier (Option 61)? I have Linux (e.g., Fedora 21) ...
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1answer
967 views

Hyper V host not showing in dhcp server client table, but guest is

So I've got Hyper V running on windows 8.1. I configured an external virtual switch which uses my wifi physical card. So I get a virtual adapter that gets its ip from my dhcp server (e3000 router). ...
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1answer
2k views

Incorrect DHCP ID (MAC address) listed for clients on Windows 2012 Server

System Info: I have an Active Directory domain controller, Windows 2012r2, running DNS, and acting as a DHCP Server. In the domain I have four Apple Mac OS X client systems (running Yosemite, 10.10.2) ...
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1answer
167 views

Why can I boot and install windows from a MS MDT server, using ISC for the dhcp server, but only under lageacy bios, not UEFI?

Setup is: Windows 2012 R2 with MDT 2013 Ubuntu Server 14.04.2 running ISC dhcp Client can be VM/Hardware doesn't matter. If I stay in legacy bios mode things work splendidly. When I switch to UEFI, ...
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239 views

2008R2 DHCP Server Becomes Unresponsive

At the end of 2013, our single Windows Server 2008R2 DHCP server started becoming unresponsive once every week or so. The server itself was up, but the DHCP server was unresponsive. Attempts to ...
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1answer
829 views

Ubuntu 14.04 can only access outside networks if using DHCP, not static IPs

I am configuring some server on Ubuntu Server 14.04 (no GUI) and I am have the following configuration: auto lo iface lo inet loopback ## Management network eth0 auto eth0 iface eth0 inet static ...
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1answer
146 views

Stuck with Cisco DHCP pool issue

Yes, I have searched, googled, sworn, googled more but have not quite found the answer I need, .. I have also posted this on a Cisco forum but, as I discovered at stackoverflow, the Stack* forums ...
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54 views

How can I assign an IP by UID in DHCPd

Here was answered how to assign an IP by MAC address. I want DHCPd server to assign IP by UID. Can i just add record to dhcpd.conf in the same manner? For example: host example { uid ...
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1answer
18 views

Change DHCP on server 2k3

Ok I am trying to mess with our dhcp settings on our domain server because at this point we kinda have competing dhcp servers between the router and the server. (Long predates me and I have finally ...
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0answers
118 views

dhcp relay with failover to local service

I'd like to set up a dhcp server which normally relays to a central site, but has a pool of addresses to hand out if the link to the central site goes down. I'm using isc dhcp server on Debian, but ...
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1answer
37 views

CentOS as a router — Can't get static IP adress for Internal Zone

I'm trying to make a router with a CentOS 7 box. enp2s2f0 ---> External Zone ---> directly connected to the internet. enp2s2f1 ---> Internal Zone ---> Connected to a PC (will be connected to a switch ...
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2answers
54 views

Group reservations in Windows Server 2k12 R2 DHCP

I am moving a mixed network from a Linux DHCP server to a Windows 2012 DHCP. Because of some of the applications our Linux users need, we need to specify different DNS servers for Linux and Windows ...
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2answers
689 views

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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0answers
48 views

DHCP from Cisco 1921 failing after switch nr 2

I have a network which uses a Cisco 1921 router. The router is connected to a Dell Powerconnect 2848 switch and from that switch is a connection to a small SOHO Planet switch which 3 computers connect ...
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0answers
137 views

“Register this connections address in DNS” - unable to automatically tick this box with a VPN connection

Hoping you can help. We have about 70 Microsoft Surface's in our network and they all have a VPN connection that is deployed from our SCCM 2012 Server. the problem I have is they will not update DNS ...
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5answers
4k views

How does a router get its IP address assigned?

I understand how a device connecting to a router (e.g. 72.73.74.75) gets assigned a local IP address (e.g. 192.168.1.5) using DHCP. BUT, how does the router itself get the IP address assigned from ...
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3answers
121 views

How do I configure all clients use proxy with out making changes to thier configuration

I am looking to configure a content filter for my network. I have squidgaurd configurared and working. I would like to have all clients use it. This includes clients I have no control over (BYOD ...
16
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3answers
2k views

Phones on some switches cannot complete DHCP process

Background I have a Windows DHCP server (Server 2008 R2) handing out addresses for several scopes. One of those scopes is for some Mitel IP Phones. The phones are configured to use dhcp option 125 to ...
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1answer
206 views

cobbler managed dnsmasq is not listening on the correct interfaces

I have a cobbler server I am trying to get installed. Unfortunately dnsmasq is not listening on the correct interfaces. It should be listening on my 192.168.10.2 network which is assigned to br1 ...
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2answers
1k views

dhclient.conf missed on centos

on centos 6 I need take the values from a dhcp server: cat /etc/sysconfig/network-scripts/ifcfg-eth0 DEVICE=eth0 HWADDR=00:50:56:27:0E:C8 TYPE=Ethernet UUID=20924b21-e92a-4944-a054-06d1967155c1 ...