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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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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32 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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66 views

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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47 views

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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0answers
11 views

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 16:49:11....
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1answer
90 views

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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1answer
27 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 - 10....
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1answer
112 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. I'...
3
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1answer
30 views

Search option in resolv.conf getting overwritten by prepend statement in dhclient.conf

I have setup a DNS server for my department which is running FreeBSD 10.2. It is currently connected to the campus internet and receiving its address via dhcp, so /etc/resolv.conf looks like this: #...
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1answer
63 views

Minimal requirements to firewall rules for running dhcpd server in linux container

I want to run isc dhcpd server in lxd (lxc) container. But it does not recive clients requests (DHCPDISCOVER, DHCPREQUEST) from clients without this rule: iptables -I FORWARD -m physdev --physdev-is-...
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24 views

Why was the previous authenticity of the host ignored?

I'm on Ubuntu 14.04 Desktop. I have just logged into other machine (Ubuntu 14.04 Server) using ssh in one terminal. I'm still connected. When I did scp in another terminal (opened earlier) to move a ...
4
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1answer
77 views

Windows Server 2012 Failover DHCP

I've been tasked with migrating from our current 50/50 scope resilient DHCP servers to new hot standby failover DHCP in Server 2012 R2. Built a test bed with the two DHCP server VMs and created a ...
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2answers
59 views

How to discard a DHCP request's old IP address (and provide a new one)?

I switched from a 192.168.0.0/24 network to 10.10.10.0/24. The addresses are provided by dnsmasq-dhcp. The switch went fine for all devices but one - a printer (called PRINTER). This printer was ...
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2answers
39 views

Cisco 1841 Router from STATIC to DYNAMIC Configuration

Basic PC-to-Internet Ethernet Configuration I'm trying to find the proper configuration in the IOS to have Fa0/0 = DHCP and Fa0/1 = STATIC-only, to allow packets from the STATIC side (inside network) ...
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1answer
37 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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2answers
33 views

DHCP issue with Cumulus and ESXi

So my switch has Cumulus Linux running on it and I have ESXi running in my network. So my main network is on 172.22.0.0/24 which has my my esxi. The networks I want esxi vms to run on is 172.22.20.0/...
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0answers
21 views

Linux clients get DHCP, Mac and Windows clients does not

I'm a sysadmin for a smaller computer lab (~40 clients and ~2000 users). We are, since this fall, seeing some weird issues with DHCP within our network. The server receives a DHCP discovery from the ...
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2answers
77 views

Microsoft DHCP only for reserved addresses

We are runing a Windows Server 2012 DC which also takes care of DHCP. Now I want to limit the DHCP-Server to all the reserved hosts to prevent DHCP leases for foreign devices as laptops, smartphones,.....
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2answers
215 views

How to have a Windows-PC registers it's name on dns server automatically

If I'm correct (please correct me if I'm wrong), a Windows-PC's name on a local network is not published via DNS but via WINS. Now let's assume I have a network with Windows workstations and I'm going ...
0
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1answer
129 views

Changing openvpn dhcp pool

I have a config at the moment which is working almost fine until some clients connect, the server starts to kick the clients off from the server or something like that. As I have checked every clients ...
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0answers
36 views

dhclient bound to recorded lease even if no DHCP server is availabe

My Ubuntu machine is connected to switch and switch is connected to DHCP server(router).Now whenever DHCP server is down but link is available through switch it tries DISCOVER multiple times. But ...
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2answers
116 views

Non-secure DNS server - Allow dynamic updates only from DHCP server

I have a standalone DNS server configured for "Secure and Non-Secure" dynamic updates. I also have the DHCP role installed on the same server. How do I ensure that only the DHCP server can update ...
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1answer
70 views

Possible to configure DHCP server to only hand out IP's to PXE clients

Is there a way when you are setting up a Red Hat DHCP server for PXE boot to ONLY hand out IPs to PXE clients? We already have a Windows DHCP server on the network (a server which we do not manage)and ...
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0answers
50 views

TFTP open timeout with ip helper

I'm setting up a DHCP / TFTP server for server provisioning via PXE. I have two hosts on the same segment (10.1.1.0). One hosts boots, gets its IP, and is able to pull the pxelinux.0 image over TFTP....
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2answers
48 views

ISC DHCP Client keeps asking for address

All of a sudden the network at my University has frozen and we managed to isolate the problem to massive amounts of UDP packets sent on the DHCP ports. On closer inspection, we found that some of the ...
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1answer
73 views

How to make a primary scope and secondary scope on DHCP server?

I am changing network structure and part of that is to change ip from 10.10.111.0 /24 to 172.16.0.0 /16 range. Now I need to have DHCP ready first in 172.16 range. I have two DHCP scope on a single ...
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50 views

DHCP not working for new pool

I created new dhcp pool(41 pool) in Windows server 2012 called vlan 41,routed with default gateway in router, added interface vlan 41 on core switch 3650, given ip help address as server address. I ...
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1answer
164 views

dnsmasq proxy mode and efi boot

So, I already have DHCP server in my local network. But I want to setup new VMs with network boot (PXE). I've setup dnsmasq in proxyDHCP mode to provide PXE info to booting clients while using other ...
0
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1answer
47 views

Does a Linux DHCP server have IP conflict prevention?

Scenario: We are migrating DHCP off our Cisco gear and onto a Red Hat 6.7 server. I am concerned about clients who will not release and renew for several days. Since the new server will not have any ...
2
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1answer
241 views

DHCP Server with multiple network interfaces and different subnets

I am trying to set up a dhcp server (isc dhcpd on debian 8 (vm inside an esxi environment)) with 4 network interfaces, eth0-3. The dhcp server should serve a different subnet on the interfaces eth1, ...
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2answers
53 views

DHCP Reservation Without Knowing MAC

Is there any possible way to have a DHCP reservation set for a device which I do NOT know the MAC address for? In other words, is there any thing that might just be unique for a certain model of ...
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1answer
110 views

How to generate DHCP Decline scenario / packets

I have a dhcp packets sniffer, which needs to log if it sees dhcp decline response coming from client.I need to know the scenario where client can send dhcp decline response to dhcp server. I tried to ...
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134 views

Force isc-dhcpd to disregard client hostname in ddns updates

I have the following configuration of isc-dhcpd-4.3.1: ignore client-updates; ddns-update-style interim; subnet 192.168.128.0 netmask 255.255.255.0 { use-host-decl-names on; update-static-...
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17 views

How to allow DHCP between 2 networks using Shorewall?

I have a server with hyper-v and 3 networks: eth0 is virtual, eth1 is physical, eth2 is extranet from ISP. Virtual network has a DHCP running and all virtual machines can reach it fine. But not the ...
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51 views

Configuring ISC DHCP server to not serve IP's on the local network

Is it possible to have a DHCP server serve subnets for multiple network segments, but not its own local subnet? I have a DHCP server on a subnet 10.x.x.x. It serves approximately 125 subnets on ...
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1answer
74 views

Windows 10 client GPO to favor DHCP server over another one [closed]

We have a cisco RV180W and a Windows server 2012R2, both acting as DHCP servers, the cisco is here to serve IP's if our server is down, but it's been a week since it has taken the lead into DHCP ...
3
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0answers
65 views

How to create DHCP reservations with long hardware address?

DHCP is managed by a Windows 2008r2 server. I want to convert a lease into a reservation so the IP will be fixed. Normally, I create a reservation based on the assigned IP address, and when the lease ...
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55 views

dhcpd.conf — one-lease-per-client statement having no effect

I have read on this and this man page that the one-lease-per-client true statement in my dhcpd.conf will stop duplicate leases to a single client. However, I am still able to sustain multiple leases ...
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26 views

DHCP: bad configuration fixed-address?

My configuration of DHCP is: dns-update-style interim; default-lease-time 86400; max-lease-time 86400; authoritative; log-facility local7; subnet 192.0.1.0 netmask 255.255.255.0 { pool { option ...
0
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1answer
30 views

DHCP reservation with virtualized AD DS

My main purpose is to provide SQL Server Analysis Services (SSAS) on a single physical machine running on say cloud provider premises. Just a remote box that should be accessible worldwide through VPN....
0
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1answer
117 views

Windows Server with Router in the same network, How to configure?

I have a network with Router that provide DHCP and DNS services to my network. Also, i have a windows server 2008R2 in the same network. I have +100 computers in the network, some must join the ...
0
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2answers
84 views

DHCP in wireless router configuration when connected to VLAN

We are attempting to create a wireless network on top of a wired network. The wireless network is will enable clinicians to use wireless devices (tablets) when seeing patients. The wired network has a ...
4
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1answer
213 views

DHCP: Create a scope within a scope

Before I joined the company I am currently working for, they set up a scope to encompass the 10.2.0.0/18 range of IP addresses (10.2.0.0-10.2.63.254). I was recently tasked with adding reservations ...
0
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1answer
84 views

How to change IP address pool in DHCP scope without affecting existing leased IPs

Within the DHCP, we have the following IP available for distribution Start IP Address 10.1.23.15 End IP Address 10.1.23.199 The current utilization of the IPs is around 50% We are looking to shrink ...
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0answers
30 views

CoreOS docker.service containers can't resolve domains

I have servers PXE booting to CoreOS with persistent state being written to disk. When I start docker containers on the host they work fine. And I have the docker.service set in the cloud-config to ...
2
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0answers
66 views

Creating additional VLANs on Cisco SG200

I would like to create 2 separate VLANs using a Cisco SG200-series smart switch (layer 2) where the devices would not see each other, while being able to connect to the internet. The setup is simple, ...
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0answers
26 views

Sonicwall DHCP timeout after AWS VPN tunnel

I have just setup an AWS VPC with a hardware VPN tunnel to our datacenter via a Sonicwall NSA 4600. Everything is working fine with the VPN between Amazon and our datacenter, but the DHCP has stopped ...
0
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1answer
55 views

Multiple IP addresses

I am developing a number of mobile websites (using IIS), and I want to test them using my mobile device which is connected on the same LAN. I would like to access each website via a different local IP ...
0
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1answer
126 views

ISC DHCP Server “Dynamic and static leases present”

i have a problem similar to Fixed and dynamic IPs in ISC DHPD lead to double lease In my DHCP-Log I often receive warnings like Jan 21 10:20:56 dc2 dhcpd: Dynamic and static leases present for 192....
0
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1answer
70 views

Hosting DHCP/PXE server on windows embedded

I am trying to boot a device through pxe, this device is connected to a windows embedded 8 (industry/standard) host pc. It should be possible I think and searches point me in the direction to using ...