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 failover/DNS not working when primary server is offline

In a VMware environment we deploy daily many new virtual hosts and for this we need a failover DHCP/DNS. Based of CentOS 7 I setup two virtual hosts as failover DHCP and dynamic DNS (dns01/dns02). I ...
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2answers
54 views

How to secure network against connecting bad device with DHCP?

I have a network with 500+ computers, at my area there is lots of cooperation companies that sometimes bring their own routers. If they do it in sneaky way and do not turn off DHCP service on the ...
9
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1answer
239 views

What are the practical risks of enabling the unsecure DNS updates on Windows?

What are the practical risks of enabling the unsecure DNS updates on Windows? As far as I found enabling the unsecure DNS updates is a requirement for enabling DHCP Linux clients from registering ...
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4answers
649 views

What happens if the DHCP server comes online after the client devices do?

If I have a Windows PC running a DHCP server. I expect it will take on order of minutes a few to boot. My network will have a variety of other devices from various vendors that will boot within ...
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12 views

Could dhclient be causing haproxy to stop listening?

I've noticed every 7 days HAProxy stops responding to requests correctly - it automatically makes firefox download a blank file in place of the website. Upon inspecting the server - everything seems ...
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23 views

Wireless clients loosing network access randomly

We have the following setup at the office: Windows Server 2012 DHCP Unifi AP (one of these rounded beauties) set up to use WPA2 with AES Zyxel ZyWALL 110 as firewall Some of the clients (laptops) ...
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14 views

Weird behavior with multiple pool inside shared networks on isc-dhcp-server

I have a weird behavior on my dhcp-server, I am using a load balance configuration and using multiple pool inside that shared-network, I have this configuration: shared-network "my-shared-network" { ...
2
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1answer
24 views

Determine when changed from static to dhcp?

We have a machine running Windows Server 2012 that is using DHCP for ip assignment, in an Active Directory network. It is standard protocol for us to use static ip and no one recalls changing this ...
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60 views

Using dhclient or dhcpcd to assign address for alias interface

I have a Linux machine with one Ethernet interface eth0 which already has one primary static address and one secondary static address (eth0:1) assigned. I would like to use DHCP to dynamically assign ...
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2answers
326 views

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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1answer
45 views

Why is the DHCP lease start time greater than the end time

On our DHCP server I see this quite a bit on some of our leases and I am not sure why its being reported like this. lease <IP Address> { starts 5 2015/08/21 13:22:20; ends 5 2015/08/21 ...
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1answer
101 views

dd-wrt DHCP forwarder is not working

all. I have a network which a Windows server is running RRAS(192.168.6.1) and another Windows server is running DC,DNS,DHCP server (192.168.6.2). I added a dd-wrt flashed router. The client connects ...
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36 views

ISC DHCPv6 reservation

I've set up ISC DHCPv6 server on a CentOS 7. Here is the /etc/dhcp/dhcpd6.conf: authoritative; option dhcp6.domain-search "example.com"; default-lease-time 3600; max-lease-time 7200; log-facility ...
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0answers
24 views

DHCP based Server not updating A record

We have Citrix Servers which get IP from DHCP. After scheduled reboots, some Citrix servers are not pingable via hostname. nslookup is not able to resolve the hostname. OS: Windows 2008 R2 Citrix ...
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0answers
31 views

How to reach a private IP (DHCP enabled) from a public facing IP through NAT?

Lets say we have computers C1 and C2 C2 has two network interfaces C2.eth0(public facing) and C2.eth1 local second physical network (addr:10.10.70.101 and Nw:10.10.70.0) Now, there are multiple ...
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1answer
79 views

Adding 4th scope to DHCP and make a superscope in windows 2012

Hope someone can shed some light here. I have a little network drama which I'm trying to get resolve as soon as possible. To give you a little background; We have CISCO SG300 small business switches ...
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0answers
14 views

Setting up developer instance dns

We have a bunch of developers that are coding webbased solutions. They want to share the solutions on their local machines with projectmanagers and QA's etc. to let them access, test and demo the ...
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1answer
215 views

Multihomed windows server 2012 r2 connectivity fails

I have a Windows Server 2012 r2 with 2 NICs. 1 local(169.254.1.1/24) and 1 "public"(conected to another local network, 10.0.10.47) interfaces. I have configured DNS, DHCP ONLY on the local interface, ...
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1answer
57 views

Split and Reserve DHCP Scope with Same Subnet

For simplicity sake, let's assume I'm trying to split my DHCP scope into two halves. On one of the halves I want to use MAC address filtering. I'm essentially trying to get a certain type of device ...
2
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2answers
202 views

VMware - VM not getting DHCP address after reboot

We are having a strange behaviour in our ESX-cluster: The Infrastructure: we have 2 ESXi 5.5.0 build 2718055 in a cluster, managed by vCenter. We are using an Essentials licence, so we do not have ...
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0answers
76 views

Windows 7 can't join in Linux domain

I installed a Windows 7 in VirtualBox and a CentOS 7 x64 too. My DHCP config is : subnet 192.168.72.0 netmask 255.255.255.0 { option routers 192.168.72.1; option subnet-mask 255.255.255.0; option ...
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2answers
281 views

Do I need a managed switch for my home network? [closed]

The benefit to home routers is that all you need to do is plug them in, and they pretty much work out of the box, allowing multiple computers to use a single internet connection. Let's say I wanted ...
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1answer
97 views

Nova network DHCP not releasing ip with force_dhcp_release=True

The problem I am seeing is that when nova-network calls dhcprelease upon instance termination (due to forcedhcp_release=True) the address is not always released(syslog are not showing DHCPRELEASE ...
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1answer
86 views

How to change broadcast-flag in Windows or Linux?

As we know there are 4 types of packets involved when a client wants to get an IPv4 address from DHCP Server. These can be seen in the image bellow (from Microsoft web site). From the perspective of ...
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1answer
110 views

Configuring Sonic wall tz 500 LAN interface with a internal dns and dhcp [closed]

I trying to configuring a sonicwall tz500. I have a internal AD server with DHCP and DNS for the domain. 10.0.0.5 is the address of dhcp and DNS. question is on the LAN 0X interface, do I assign it a ...
2
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1answer
165 views

dhcp not assigning gateway

So I am running a dev server for KVM virtual machines. I have a DHCP server running locally on the host node with the following configuration: /etc/dhcp/dhcpd.conf ddns-update-style none; ...
3
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0answers
52 views

Authentication and logging of users for a Wireless ISP?

I have to upgrade a Wireless ISP's (WISP) network. Their current setup consists of a router (Mikrotik RouterBoard 1100AHx2), Ubiquiti Rockets (with sector antennas) for clients, and Ubiquiti ...
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1answer
79 views

Linux DHCP for multiple subnet

vlan10---->firewall----->linux dhcp server vlan20---------↑ I have two vlan(vlan10 and vlan20), and I would like to use Linux DHCP server to centralize IP address designation. In fortigate firewall ...
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3answers
113 views

Intel AMT and host get different IP addresses via DHCP. How to fix?

I have a server that's recently been crashing occasionally in odd ways, so I decided to configure up Intel AMT on it in the hope of being able to reset it remotely when this happens. For better or ...
1
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1answer
70 views

All DNS entries are set to static

I have a WS2008 R2 server acting as DC, DHCP and DNS server. DHCP is set to always dinamically update DNS-A and PTR records on behalf of clients, DHCP name protection is enabled and DHCP credentials ...
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1answer
46 views

Why would a DNS server issue affect only one corner of a building?

I got a complaint today from an end user whose internet was extremely slow only inside his office. Every other location in the building was fine, and the signal strength was very high even inside the ...
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1answer
34 views

Ubuntu ramdisk template

I've been working on a ramdisk template for running a complete root filesystem on the RAM of a baremetal server(over IPMI so no physical access) that boots over PXE. I used debootstrap to create an ...
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0answers
38 views

Dell PowerConnect 5324 ignoring DHCPOFFER

I've recently procured a "new" Dell PowerConnect 5324. The firmware is updated to the current version and most of it works just fine. The exception is DHCP. When I enable DHCP, it cannot seem to ...
2
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1answer
118 views

Microsoft DHCP server giving “old” lease to clients switching networks

I have 2 Windows Server 2012 R2 DHCP servers running in active/active load-balancing on one of the networks. DHCP requests from the other networks are DHCP relayed by the router to these DHCP servers. ...
0
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1answer
182 views

Ubuntu Server 15.04 as Router and DHCP Server with multiple subnets

at my company i got assigned to build a new network, where 1 ubuntu server manages DHCP for 3 subnets, allows communication of these subnets between each other and shares the connection to the public ...
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0answers
202 views

no default gateway on interface that is set up with DHCP on CentOS7

I am using CentOS7 with multiple interfaces (ens161, ens192, ens224, ens256). The box has all static IP's with the exception of one interface that is set up to DHCP (ens192). ens192 is set up as ...
0
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1answer
57 views

Bridged VirtualBox VM with individual IP

On Debian hosts I run VirtualBox VM mainly to run WinX software. Some of these VM shall join AD and as such need fixed IP and shall be reachable from the LAN, i.e. NAT is no option. I considered ...
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1answer
81 views

How to receive email notification of non-AD joined DHCP leases?

This answer to theCleaner's question helped me some Windows DHCP Server - get notification when a non-AD joined device gets an IP address but the answer to his question involved Quest Poweshell ...
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1answer
69 views

Access to local dhcp server via ssh [closed]

I constructed dhcp server on centOS6 (which has a ipaddress 192.168.0.0) to allocate ip address, 192.168.0.5, to other local node. When i use "service network restart" on client node and type ...
2
votes
1answer
99 views

Windows Server 2012 r2 standard with dual NIC + DHCP

Currently I have a physical host with Windows Server 2012 r2 standard installed and DHCP role enabled. In addition the physical host has two network interface cards. I am planing to connect the ...
2
votes
1answer
62 views

Configuring DHCP server (Win 2012)

I am trying to do some basic testing of a DHCP server (Windows Server 2012). I'm trying to do all this testing from a laptop. The VM's are set Host-Only (or 'Private to my Mac' setting) To get ...
0
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1answer
244 views

TFTP boot file download aborted during PXE boot up

I'm using OpenDHCPServer together with OpenTFTPServer in order to try out network booting. My problem is after acquiring IP address client starts downloading the boot file and halts. Message in TFTP ...
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0answers
29 views

“Add Server” in MMC not showing fqdn. Any ideas?

and Nothing is "broken" but my curiosity (and sadly O.C.D) has my wondering why when I add another server through MMC it doesn't show the fqdn of the "added" server, just the hostname. Tutorials ...
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0answers
247 views

dhclient: No broadcast interfaces found, but eth0 is up and broadcast

I'm experiencing a common problem with dhclient. But I wasn't able to find a clear solution to this problem. System: ReadyNas RN104 Stock Debian for armhf Just upgraded to Debian Jessie (now ...
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1answer
49 views

Why are DHCP request and acknowledgment messages broadcasted and not unicasted?

In 'Request' part of the DORA process, IP and MAC address of the DHCP server is known to the client (as the IP datagram sent in Offer has this information). So if the destination is known, why is the ...
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79 views

Ubuntu MAAS: PXE only booting two nodes at a time

I'm currently setting up an Ubuntu (15.04) MAAS (1.7) cluster for the first time. It seemed quite straight forward and I even figured out how to boot VMs running on vSphere, so I have a nice testing ...
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3answers
243 views

How would a PCAP filter look like to capture all DHCP related traffic?

As I understand it, for IPv4 I would need to capture UDP port 67 and 68, ARP, ICMP echo request and reply, and for IPv6 I would need UDP port 546 and 547, all DHCP-related multicast addresses, ...
0
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1answer
95 views

Why is my DHCP pool not working?

I'm trying to create a configuration and it's doing most of what I want it to do, but the DHCP pool isn't assigning addresses. Here's the config so far: enable config t hostname xxxxxx enable ...
0
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2answers
157 views

Using the VLAN of a bridged switch

In our building, we have 2, 6509 core switches, one for our company, and one for another. We have a vlan configured with a /30 which bridges the 2 switches. Both of us are on separate /16 networks. ...
0
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1answer
272 views

Event ID 1340 - DNS registration for DHCPv4 Client & DHCID has been denied (DHCP Name Protection)

Event ID 1340 warnings are consistently being logged on a Server 2012 R2 domain controller in the System log whenever Apple/Mac clients connect to the network. Here's a log example: Log Name: ...