Questions tagged [dhcp-server]

Dynamic Host Configuration Protocol (DHCP)

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Linux Bind9 DNS server, configuration throwing errors

I am having problem with DNS configuration in Linux. I am using isc-dhcp-server as DHCP server and bind9 as DNS server, but I it returning me errors. This is my Setup Internet <--enp0s3 interface--&...
mitas1c's user avatar
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How do I deploy correctly my DHCP Servers with DHCP Option 82?

My Goal is to achieve a seperate DHCP Pool on my switches, how am I able to achieve it on a flat network hosted for a LAN-Party. Which means seperate VLANs should be avoided We're talking about ...
Gamienator's user avatar
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Different gateway for a single host in DHCP server

I am using ISC DHCP Server and I want to assign a different default gateway for one of the devices using that DHCP. I have the network 192.168.0.0/24, and two redundant ISC DHCP servers assign IP ...
nobody's user avatar
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DHCP providing IP but not creating DNS A record

I'm having a problem setting up a virtual machine IP assignment via DHCP. The virtual machine is a clean installation of Ubuntu Server 22.04 The DHCP server is a Windows Server Domain Controller. When ...
Eduardo Poças's user avatar
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2 answers
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How would you set up a macOS laptop to maintain the same IP address between ethernet and wifi?

I have a situation where I need to maintain the same IP address and/or hostname between two network interfaces on several macOS laptops: the ethernet and wifi. The topology is such that there is a ...
ylluminate's user avatar
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Devices keep getting IP from previous VLAN

Some devices (printers and laptops) that are moved to another building with a different VLAN will not release the IP address assigned. I noticed this first when a laptop reported no network ...
Rick's user avatar
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DHCP failover with PXE

I'm trying to set up DHCP failover with PXE booting allowed from one of the DHCP servers. As required by the DHCP specification, I've setup separate pools for "regular" DHCP and for PXE ...
William Seligman's user avatar
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Wrong DHCP-Adress when switching VLANs

I have a problem with our fairly new kea-dhcp setup. We have a bunch of different VLANs in use for which we want to give out DHCP-Adresses. For this purpose we use a little APU-box which serves our ...
paddex's user avatar
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Change DHCP range and tcpip connections

I want to change the dynamic range of my DHCP server for a network e.g. it is at the moment from 192.168.0.2 to 192.168.0.100 I want to move it from 192.168.0.101 to 192.168.0.200 but I don't want to ...
AAB's user avatar
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ISC DHCP server web interface

I want to ask what web interface could be used for isc dhcp server on Ubuntu 22.04 server. I want to create dhcp server on ubuntu, I installed and configured isc dhcp but now i want to manage it from ...
skoczo's user avatar
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Windows Server 2019 DHCP Option 33

Noticed there is an option in DHCP for static routes, looks like it is using a server name and an IP that you assign, is this the same thing as adding an entry into the host record like we used to do ...
Davids Learnin's user avatar
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deploying pfSense in OVH public cloud as a DHCP server in HA

I am trying to deploy two pfSense in the OVH public cloud (OpenStack). Each has its own public IPs and public connectivity works without any problem. Things become more complicated on the vRack part (...
Dboy's user avatar
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Getting IP address from another subnet's DHCP

As in the diagram below I have two routers on two different subnets. I connected them together but have not set static routes yet. Network Diagram However, when connecting from Access Point A's SSID, ...
Reedz's user avatar
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DHCP renewal can't go through because DHCP server is down

To my experience, if a DHCP client tries to renew its lease, but the DHCP server is down, and after the lease time is over, there are two possible scenarios: The client keeps the IP The client goes ...
AhmedWas's user avatar
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How to manually purge dhcpd.lease?

How do I manually purge ALL dhcpd.lease ? Can I just sudo echo /dev/null > /var/lab/dhcpd/dhcpd.lease ? It's a special use case of testing ground; we have an isolated LAN for developers to do test ...
RichardLiu's user avatar
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Reserve IP based on DHCP Option 61 insted of MAC Address

a DHCP client is sending a discovery packet with option 61. Now the Windows server 2019 /2022 needs to respond with the offer based on the DHCP reservation, reservation is registered based on option ...
Abel K.Bil's user avatar
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1 answer
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DHCP server does not provide correct filename for PXE

I'm trying to configure PXE server for both Legacy/UEFI support. So I need to provide different bootloaders based on architecture of machine. Here's part of dhcpd.conf: option architecture-type code ...
SibVal's user avatar
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Windows DHCP IOT retain same IP

I am trying to address a problem. We have a windows DHCP server and some devices, which we need to replace on needs. The device has a custom DHCP client which sends DHCP-DISCOVERY Packet with ...
Abel K.Bil's user avatar
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1 answer
634 views

Centos 7 dhcp server not responding to UEFI PXE DISCOVER

I'm trying to set up a Centos 7 server as a dhcp server for PXE (UEFI). I'be tried several changes to the dhcpd.conf file, but nothing seems to make a difference. dhcpd.conf: allow booting; allow ...
Justin Killen's user avatar
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1 answer
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Migration strategy to migrate a DHCP scope from old DHCP server to new DHCP server as smooth as possible

My current homeLab and entire home is currently running on a single subnet 192.168.0.0/24 with my ISP provided router running a DHCP scope handing out addresses in the 192.168.0.20-192.168.0.254 range,...
Simon Kepp Nielsen 's user avatar
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1 answer
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Force sending DHCP options

I have a lab spectrometer that boots using PXE from boot files stored on a computer. They exist inside a local network with the computer acting as both the DHCP and TFTP server. The spectrometer ...
HKaras's user avatar
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Setting up LAN gateway for school club network - "No subnet declaration for enp3s0"

I am a computing teacher, I am trying to setup a "sandbox" network with internet access for an after school computing club. I have an old PC (Debian 11 installation) with 2 ethernet ...
ICT Teacher's user avatar
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DHCP logs showing (no free leases)

I have setup new isc-dhcp-server in ubuntu 20.04. all client getting connect but showing there logs (no free leases) client connected only 25 machine. sudo tail -f /var/log/syslog Sep 9 09:43:57 ggn-...
Aslam Raza's user avatar
1 vote
1 answer
344 views

How to send custom DHCP option on all Offer and Ack packets in kea?

I'm using the Kea dhcp server, and I want to use the DHCP options to send data to the server's clients. Following the instructions here, I listed the option with the "always-send": true ...
Jarred Allen's user avatar
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1 answer
1k views

Decode UID from dhcpd.leases

I have am testing a device on my network which has this lease assigned: lease 192.168.110.85 { starts 3 2022/07/20 16:12:37; ends 3 2022/07/20 16:22:37; cltt 3 2022/07/20 16:12:37; binding ...
Johannes Linkels's user avatar
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2k views

dhcp: lease expiration vs. infinite lease

As per RFC2131, when the lease expires the client has to stop using the IP address. So do I understand right that if the lease lifetime is set to infinite on the server, then the client does not need ...
Mark's user avatar
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126 views

libvirt and dnsmasq does not allow to start Kea DHCP server

I have libvirt installed which instantiates dnsmasq process per each virtual bridge interface, e.g. virbr0, however for some reason I can't start kea-dhcp server on other interfaces in the system, ...
Mark's user avatar
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Freeradius with dhcp server: Calls to perl module returns error

This is a continuation of my previous question in sending static routes from Freeradius DHCP server implementation in combination with Strongswan VPN server. When debugging Freeradius using tcpdump ...
Lasse Michael Mølgaard's user avatar
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isc-dhcp-server ip-range speicifc domain-name-server

I'm trying to get an isc-dhcp-server configuration to use different DNS-Servers based on the ip-address assigned. Basically, I want some of my client marked as not-trusted, which then may not access ...
Poehli's user avatar
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1 answer
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Migrating Old Active directory Forest with two domains

We have single AD forest with two domains as follows: Domain A: Contains nearly 30 servers (7 physicals and 23 VMs) all hosted on Microsoft Hyper-V server Nearly 500 Active user accounts A huge file ...
John Rese's user avatar
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1k views

Obtaining two DHCP addresses on Linux

There have been various questions asked a long time ago about obtaining two IP addresses via DHCP on Linux. Most of those are still relating to old 'alias interfaces', like eth0:0, which has been ...
Michael Firth's user avatar
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1 answer
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ScreenOS SSG-320M Source Interface Based Routing

quick question. Couldn't figure this out with even the ScreenOS Bible. Juniper SSG-320M Firewall, Just added an 8port PIM Module(ETH1/0 to 1/7): ETH0/0(Trust) 172.16.1.1/16 ETH0/2(UnTrust) 192.168.0.5/...
Chalen's user avatar
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DHCP server IP reservation during the "offer" step

How long is the IP reserved by the DHCP server, when it sends the offer message? Imagine the client does not send back the request message, after how much time is the IP available again? Thanks for ...
ragnar's user avatar
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2 answers
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Our cable modem is acting as a rogue DHCP server, even though its DHCP function is supposedly disabled [closed]

We have, for quite some time, had problems with systems on our LAN coming up "bottled," i.e., with non-functional connections. I recently noticed that the assigned IP addresses looked like ...
hbquikcomjamesl's user avatar
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1 answer
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Using DHCP reservations instead of static IP address configuration for servers

I was wondering if it is better to use DHCP reservations for servers and computers that must have static IP address, excluding DHCP servers themselves, Domain Controllers, and DNS servers of course, ...
Zoran Jankov's user avatar
0 votes
1 answer
208 views

static bindings in DHCP server

I'd like to enable static binding in the DHCP server (I'm using KEA Dhcp https://www.isc.org/kea) but I think it is applicable to other implementations as well. What exactly I want to achieve is to ...
Mark's user avatar
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0 answers
2k views

dnsmasq DHCP not working, not replying to DHCP requests

I have setup dnsmasq as DHCP server on a CentOS VM, however it is not replying to DHCP requests. What could be the issue? Following is the configuration and tcpdump logs. interface=ens224 listen-...
asm_nerd1's user avatar
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Can't start isc-dhcp-server due to error " AgentInitCheck: agent comms failure"

I have a Raspberry Pi 4 - Model B, and I'm trying to create an adapter from Wi-Fi to Ethernet using the Pi. I'm currently using this gist as a guide for how to create it, but I keep running into an ...
frissyn's user avatar
0 votes
2 answers
543 views

ISC DHCP/DDNS setup: Static entries for non-dhcp clients

I have set up a local network with ISC BIND9 and DHCP service. New leases trigger the DHCP to add an A and PTR record which works perfectly. I also added lots of static host entries in the dhcpd.conf. ...
dom's user avatar
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2 votes
1 answer
3k views

Identifying current main DHCP server

There are two DHCP server of the same IP address example.(10.100.9.12 and 10.100.9.13). The gateway, subnet mask, and DNS is the same. The current DHCP are running on Vlan9. Is there any possible way ...
Torlarp Leenabanchong's user avatar
1 vote
1 answer
3k views

Windows DHCP not showing the accurate leases

In Windows System Event log, there are DHCP server warnings that IP address range of a scope (10.40.0.0) that available is low. Windows Event Log But in the DHCP program, the Address Leases is only ...
Boon Chye Phang's user avatar
1 vote
1 answer
4k views

DHCP NTP Server Option 042 not propagated by Windows Server 2016

I am trying to make NTP server settings available to our non-Microsoft devices on local wired and wireless network. Obviously, they don't know how to use MS AD time info from domain controller. Our ...
mt42's user avatar
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0 answers
1k views

Problems with WDS on different subnets

I'm setting up a WDS (Windows Deployment Service), the WDS server is in a different subnet than the clients that need PXE. These subnets are connected through a VPN tunnel. Routers are pfsense. But on ...
tomas's user avatar
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0 votes
1 answer
435 views

isc dhcp multiple option 240 in same subnet

I'm fairly new to isc dhcp. I'm working at an ISP and need to provide our STB's with an option 240, and it has worked fine for years, the problem now is that we are getting a newer model, that needs a ...
Danny Christensen's user avatar
0 votes
2 answers
1k views

Query IP/hostnames in local network (Windows)

I have a Windows Server based network, running a Windows DHCP and DNS server. How can I list all the computers in the local network known to the server? That would mean querying either the DHCP or the ...
jdm's user avatar
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-2 votes
1 answer
51 views

Going to implement new Infrastructure in HQ Office with 1 firewall, 1 L3 Switch, 5 L2 Switch, 2 Managed WIFI AP and 1 Server [closed]

Im going Implement Network in HQ Office which will link also with Branches Office. What IP Address Class is recommended on this scenario? Need some assist to Kick Off on this. I have 1 unit Fortigate ...
adrian chin fuk loi's user avatar
-1 votes
2 answers
1k views

How does a client find the DHCP server on network if DHCP is disabled on the router? [closed]

I am an acting, self-taught network administrator, so please excuse me if this should be obvious. I have a Windows network with domain controllers running DHCP. My gateway/router is a Meraki MX67 that ...
David Christian's user avatar
-1 votes
1 answer
172 views

What is default IPv6 configuration on routers

I've just started learning IPv6. I have a router running OpenWrt and I would like to configure it to use IPv6. As I know this address can be assigning to a client with or without DHCPv6 server. Do you ...
tomi7654's user avatar
0 votes
1 answer
533 views

DHCP Pools on Ubuntu DHCP server not working properly

Mac addresses ending with "55:a3" and "56:2a" are also ending up in last pool 123 match if binary-to-ascii(16,8,":",substring(hardware, 5, 6)) = "55:a3"; ...
Anand Bajpai's user avatar
1 vote
2 answers
360 views

dhcpd server invalid MAC detection

On my DHCP configuration, I have on commit hook to save device information. My problem is some of the MAC addresses becomes invalid: 8:7c:39:cf:b6:3f - this should start with zero 8:d0:b7:52:f9:68 - ...
hodl's user avatar
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