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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Wireless router not allocating correct IP addresses

I have a WAG320N wireless router setup as a DHCP relay to my Windows 2003 R2 Enterprise server. The IP of the router is 137.248.21.1 The IP of the server is 137.248.21.10 The scope for the server is ...
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483 views

How can you route DHCP requests through a non-default gateway?

I'm hosting some KVM virtual machines on a server with two NICs, eth0 and eth1. I have two networks 192.168.100/24 and 192.168.200/24. I have set up bridges as per ...
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263 views

Windows Server 2008 DHCP with RRAS

I have a Windows Server 2008 R2 which is a member of a domain, but is placed in a remote location. The server is directly connected to Internet. Clients need to access a particular insecure TCP ...
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903 views

Cisco ASA - DHCP Relay doesn't seem to be working consistently

I'm having an issue where some users on one of our DMZ networks aren't getting a DHCP address from the Windows DHCP server on our internal interface. Being that not everyone is affected is making ...
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292 views

associate dhcp requests with subdomains in dnsmasq

I have dnsmasq running as a dns server with a number of linux boxes using static ips that run several virtual hosts on subdomains. I currently have the following address line in my dnsmasq.conf to ...
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17 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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39 views

DHCP Server configuring

I've been configured DNS and DHCP on Windows Server 2012 correctly. But when I open the DHCP server from start menu and server manager, I get different result. When I run DHCP manager from server ...
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53 views

Internet drops out randomly for short periods of time (LAN issue)

I run a network (I'm just a math teacher) at my school. We get random 10 or so minute periods (I'd guess three a day on average) where the Internet is not accessible from within the LAN. If I go to ...
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42 views

Why need DHCP Relay (Watchguard) inside the Trusted network?

I run a small network that looks like this: { Win 2008 server , desktops , Wifi AP} -> Switch -> Watchguard XTM21 firewall (the Switch is connected to the XTM's Trusted interface ; the XTM ...
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16 views

Change network mask DHCP server

Currently i have a Ubuntu with isc-dhcp-server running with the following configuration authoritative; ddns-update-style interim; ignore client-updates; subnet 192.168.1.0 netmask 255.255.255.0 { ...
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83 views

Sonicwall L2TP Server is using a “phantom” internal DHCP server

Following a few articles on options 121 and 249, I'd like to push out routes to the L2TP VPN clients using the internal DHCP server on the Sonicwall. However, the Sonicwall seems to be using a ...
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29 views

How to identify hosts with bridged adapters

We have an issue with our Windows DHCP server randomly having bad address errors. The current top theory is that there is a host within that pool with bridged network adapters, causing all sorts of ...
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18 views

What is the default behavior when a RHEL 6.x DHCP client fails to renew its address?

I have had experience with some RHEL 6 servers that were found unreachable, and investigation of the console revealed that they had failed to renew their IP address, and eth0 was without an IP. There ...
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45 views

DNS options on Cisco switch providing DHCP

At the company work for we decided to move DHCP duties from a Windows server to our 3750-X switch stack that's the gateway for our network. I researched the commands needed and cobbled together the ...
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26 views

Draytek AP Wireless Bridge IP Issues For LAN Devices

OK, I have a very messy network at my office, piggybacking off a neighbor's WIFI for internet (with their permission). I have a Netgear Router + DNS (DGN2200) connecting via LAN to a Draytek 800AP. ...
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37 views

How to fix stalled connection on large download

I have a cisco 1921 router performing routing and NAT function. Cisco 3750 is performing layer 3 core switching duties. Users are complaining about large file transfers being stalled (not dropped) ...
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41 views

WDS and DHCP - PXE-E11/55 errors

I have been doing some testing with MDT/WDS and yesterday, out-of-blue, my virtual PC doesn't want to boot from a network to WDS server. Here is the setup (all stations are virutulized, vSphere 5.5): ...
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82 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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183 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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167 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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262 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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52 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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2k 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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105 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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93 views

dhclient doesn't get/ack offer on macvlan interface

Following this is excerpts of logs when trying to configure a macvlan interface. For some reason unknown to me, dhclient doesn't seem to get/ack the offer, how come? --- /etc/network/interfaces auto ...
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13 views

IBMi DHCP Dynamic DNS not communicating to DNS Server

I have a single IBMi server set up with a DHCP and DNS server running on it. I have set up the DNS forward and reverse zones for the local network to allow for dynamic updates, and I have set the ...
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91 views

Edge firewall on Ubuntu, dynamic IP address, static DNS

We're setting up a software firewall, and one of the issues we're facing is that eth0 has a dynamic IP address. In /etc/network/interfaces we've got the following: # The loopback network interface ...
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77 views

Server 2012 DHCP Policy for Polycom MAC addresses

I am setting up a Server 2012 DHCP Server and I want to apply a Policy to assign our Polycom phone within a specific IP range. I have created a policy using MAC address equals 0004f2, which is the ...
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207 views

How to get host-name from DHCP server via Network Manager?

I can get hostname and ip address from DHCP server with invoking the script under /etc/dhcp/dhclient-exit-hooks.d/ directory as explained here on client side. I assigned host-name and ip address in ...
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92 views

isc-dhcp-server sends OFFER to ip and not broadcast

I'm trying to set up the isc dhcp server. My config looks like: ddns-update-style none; default-lease-time 600; max-lease-time 7200; # If this DHCP server is the official DHCP server for the local ...
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158 views

theforeman 1.4: foreman-proxied external dns/dhcp server puts provisioned domainname twice in dns server

I have a strange problem with our foreman. we use .localdomain as our internal domainname (eg. a host gets the fqdn test.localdomain) we use the standard dhcpd and named from CentOS6, both on the ...
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209 views

No A records created by DNS client on Windows Embedded Standard 2009

Windows Embedded Standard 2009 is basically Windows XP. I have thin clients running this OS which get configured through DHCP. I haven't been able to make them register an A record with the DNS server ...
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201 views

dhcpd log being flooded with duplicate and uid leases

I am runnig centos 6.4, isc-dhcpd-4.1.1-P1. I have over 100 desktop laptops on win7. my dhcpd.log file is being flooded with following messages Mar 3 11:08:06 tanaga dhcpd: DHCPREQUEST for ...
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86 views

BMC nics are blocking DHCP offers from reaching target nic

In our environment we have a range of Dell and HP servers with two mac addresses for one interface, one mac for the BMC and one mac for the nic itself, but they share the same physical interface. ...
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252 views

Configuring an IPv6 FreeBSD router works on boot only

I am trying the following: I am having a DHCPv6 server (machine A) with a /48 subnet which will delegate /64 subnets to other routers using the prefix delegation mechanism. One of these routers is a ...
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475 views

CentOS DHCP server not updating DNS nameserver on Ubuntu Client

I have a working DHCP server on CentOS, with /etc/dhcp/dhcpd.conf set up as follows: subnet 192.168.1.0 netmask 255.255.255.0 { option routers 192.168.1.1; option subnet-mask 255.255.255.0; ...
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72 views

coova and dhcp server running on same device?

I need to run coova on a device that does not easily disable it's built-in DHCP server or the IP address on the WiFi AP interface facing the WiFi clients. This means both coova DHCP and device ...
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71 views

How to setup metric for routers on CentOS DHCP server

I have a simple DHCP server running on CentOS 6 with the following configuration: subnet 192.168.1.0 netmask 255.255.255.0 { allow booting; allow bootp; ddns-update-style none; range ...
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41 views

DHCP Randomly Not Assigning Addresses

Having a strange issue for the past day or so. Some users (probably about a dozen, dozen and a half out of 100 or so) are having trouble pulling DHCP. They are getting the private IP address. If I ...
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114 views

How do I stop a Linux computer from sending a DHCP hostname?

I need to set up a Linux computer so that it uses DHCP but doesn't send any hostname at all. I'm using isc-dhclient-4.2.4 /etc/dhcp/dhclient.conf contains the line send host-name = gethostname(); ...
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155 views

Laptop using DHCP lease from another network

We have a laptop with intermittent wifi connectivity problems. Rebooting often helps. Today while digging around I noticed that its DHCP IP address and gateway are not addresses on our subnet. The ...
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68 views

DHCP server with ability to update mac address dynamically

Is there a better way to maintain MAC to IP specification in dhcp with out restarting dhcp service each time when there is an update. is it possible to use DHCP with database in Linux to save all ...
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1k views

CentOS 6.4 - Cant get an IP from DHCP

I have a Ubuntu and CentOS system running on XenServer. The Ubuntu Box gets and IP from DHCP no problem. The CentOS will not take a DHCP but a static address works fine. [root@XenCentOS ~]# service ...
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128 views

How does DNS update work in an environment where DHCP performs registration, and clients may have multiple DHCP leases?

Here are the particulars (all Windows): DNS - Our DNS only stores one A-Record per hostname. Scavenging is not currently enabled. DHCP - DHCP is configured (server level) to perform DNS registration ...
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179 views

Configuring HP Proliant iLO using hponcfg

I am configuring an iLO using hponcfg by logging into the machine remotely and running hponcfg with scripts Mod_Directory.xml and then with Mod_Network.xml. I am enabling the DHCP on the device. But ...
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374 views

name not resolve in vmware client PC

I have configured DNS server and DHCP sever on centos 6.2 vmware virtual machine. I have a windows xp vmware client machine. nslookup command is work in server terminal But it won't work in windows ...
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151 views

Create a DHCP working lab in HyperV (2012) all Internal

I need to create a lab for testing purposes. I got a good desktop on which i have installed a server 2012. In HypverV, i have installed two 2012, one XP and one W8. The idea is that the one and ...
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277 views

How to filter out/disable DHCP NAK responses?

We have some crappy situation where we don't have control over the existing DHCP server on the network and where we need to add another BOOTP/DHCP server with the authoritative directive. Our ...
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153 views

DHCP requests don't get to instance, but they do if I retransmit with scapy

Trying to troubleshoot a problem where DHCP request packets aren't getting into a KVM virtual machine. The DHCP server and the hypervisor are on separate machines, separated by a swich. br100 ...
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63 views

IP Helper Policies

So I'm fairly new in the higher-end Firewall market - but recently have purchased a Sonicwall (2nd hand for lab) for lab purposes. I have a LAN interface configured on 192.168.0.1 and a Wireless AP ...