2022 Developer Survey is open! Take survey.

Questions tagged [isc-dhcp]

ISC DHCP is open source software that implements the Dynamic Host Configuration Protocols for connection to a local network. It is a reference implementation of those protocols, but it is also production-grade software, suitable for use in high-volume and high-reliability applications. DHCP is available for free download under the terms of the ISC License, a BSD style license.

Filter by
Sorted by
Tagged with
0 votes
0 answers
9 views

Load Balancing ISC DHCP Servers Issuing Multiple Offers to Client

According to section 6 of RFC 3074, it seems that the process for selecting a load balancing server in ISC DHCP is as follows: The client broadcasts a discover message, which either directly reaches ...
user avatar
  • 11
0 votes
0 answers
5 views

RFC 3074 DHCP Load Balancing STID vs RFC 2131 DHCP xid

Section 2.2 of RFC 3074 defines a Service Transaction ID (STID) as: An attribute of the individual client requests used for load-balancing. However, section 2 of RFC 2131 defines the xid field of a ...
user avatar
  • 11
0 votes
0 answers
29 views

ISC DHCP for relay agents

I would like to configure DHCP server for my networks, but in the same time, i don't want to setup dhcp server on the network where the server itself is. DHCPD insist to configure subnet declaration ...
user avatar
0 votes
1 answer
24 views

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 ...
user avatar
  • 103
1 vote
1 answer
24 views

What is the proper way to back up ISC DHCPd lease files?

According to this answer, DHCPd lease files are cleared every hour. The goal is to back up the leases file continuously, so there is never a lease lost. This is made difficult since it is unclear ...
user avatar
  • 11
0 votes
1 answer
109 views

Simple stateful DHCPv6 using ISC DHCP and RADVD. Doesnt work?

I'm trying to set a simple ipv6 network using ISC DHCPv6 on a linux machine. Here is my dhcpd6.conf: subnet6 beef:fade::/112 { max-lease-time 3600; range6 beef:fade::100 beef:fade::fffe; } The ...
user avatar
0 votes
0 answers
33 views

Ubuntu 20.04 false subnet per interface isc-dhcp-server

This morning I have configure my interfaces network: version: 2 renderer: networkd ethernets: ens160: dhcpd4: true nameservers: addresses: [8.8.8.8,...
user avatar
0 votes
0 answers
52 views

isc-dhcp-server not replying to relayed requests

DHCP request is being relayed from a server in a different subnet to the ISC-DHCP box. ISC-DHCP is not responding dhcpd.conf is like this: subnet 10.0.1.10 netmask 255.255.255.254 {} host test { ...
user avatar
  • 21
0 votes
0 answers
40 views

DHCP Kea High Availability over TLS doesn't work

I have installed 2 Kea 2.0.1 Servers in Debian 10 Buster virtual machine in Virtual Box 6.1.26 r145957 (Qt5.6.2) and also in VMware Workstation Player 16.1.2 build-17966106.The high availability ...
user avatar
  • 1
0 votes
1 answer
18 views

Dynamic Google hosted DNS zone update by DHCP

I have dns zone running in Google Cloud. I would like to integrate my ISC-DHCP with that zone by enabling automatic host registration into the zone. I'm looking for some analogy to enable in Google ...
user avatar
  • 101
0 votes
0 answers
55 views

ISC-DHCP and BIND 9 DNS: DDNS update fails for /27 subnet

I have a problem with DDNS update with ISC-DHCP server. My /etc/dhcp/dhcpd.conf subnet section that doesn't work is: subnet 193.198.186.192 netmask 255.255.255.224 { range 193.198.186.200 193.198....
user avatar
  • 121
0 votes
0 answers
54 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. ...
user avatar
  • 1
0 votes
1 answer
196 views

DHCP server failover with dynamic bootp range declaration

I am trying to configure a failover for a ISC dhcp server running on Linux that has dynamic-bootp range declaration. The configuration file looks like this (I am trying it locally first, therefore ...
user avatar
  • 3
0 votes
0 answers
94 views

Allow and deny class statements in isc-dhcp-server config

When allowing one subnet to use a class, do you have to deny "all other subnets" explicitly. Or is it enough to just to allow the class on the subnets that should use that class, and all ...
user avatar
  • 101
0 votes
0 answers
80 views

ISC Dhcpv6 pool

I recently set up a dhcpv6 server in my network. The problem is: I set the range of it to #VLAN120 subnet6 2001:470:2249:120::/64 { range6 2001:470:2249:120::20 2001:470:2249:120::250; ...
user avatar
  • 1
0 votes
0 answers
47 views

ISC DHCPv6 on Opnsense execute script

In the ISC DHCP Server that ships with opnsense exist the possibility to run your on scripts triggered by certain events. I want to execute a script whenever a dhcpv6 lease is commited to a client. ...
user avatar
0 votes
0 answers
264 views

isc-dhcp 4.2.5 does not support dhcp-client-id and vendor-class-id?

I have isc-dhcp-4.2.5 server and client installed on two CentOS-7.4 boxes. I know this is quite old distro, but I can't change it for various reasons. Dhcp server configuration: option domain-name &...
user avatar
  • 195
0 votes
0 answers
59 views

DHCPv6 with ISC

I am building a network and I got stuck while setting up the DHCPv6 Server with isc. I was looking in internet for any documentations, but wasn't able to find anything. I created 2 test vlans - Vlan5 ...
user avatar
  • 1
0 votes
0 answers
51 views

Parsing dhcp-parameter-request-list

I am actually trying to parse the dhcp-parameter-request-list and see if it contains option 143 in the list. If it contains 143 option, then I have to respond with a 143 message with bootstrap server ...
user avatar
0 votes
1 answer
105 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 ...
user avatar
1 vote
1 answer
497 views

isc-dhcp-server assigns same IP address for different hosts

I have an isc-dhcp-server running in a Docker container, which I configured with one subnet of 100 available IP @. When starting my laptops (they are all running Linux OS), when they are requesting IP@...
user avatar
  • 13
0 votes
1 answer
88 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"; ...
user avatar
0 votes
1 answer
65 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 - ...
user avatar
  • 101
0 votes
0 answers
135 views

isc-dhcp-server can't get DHCPDISCOVER packet from some clients whose MAC address not in the subnet

isc-dhcp-server running normal, it can offer IP address to most clients in all subnet which are defined in the dhcpd.conf file, but it can't receive some DHCPDISCOVER packet from several clients which ...
user avatar
1 vote
0 answers
532 views

What is the exact meaning of "On Commit" in ISC DHCP server configuration?

I know there are three kinds of events we can use for scripting in ISC dhcpd -- commit, expire and lease. My problem is, I am having a little problem in understanding the "commit" event. I ...
user avatar
  • 11
1 vote
1 answer
1k views

how to load grub with menu in ipxe setup

I am trying to setup an ipxe environment on a vmware. I would like to configure the setup with UEFI. I have setup a ubuntu-server and configured it as pxe-server. via downloading ipxe, isc-dhcpd, tftp-...
user avatar
0 votes
1 answer
311 views

Define multiple filename options in DHCP config based on different range

Intro I am trying to use a centos box for DHCP and TFTP function, for iPXE boot. I have one subnet configured for DHCP, but it has multiple ranges and each range has a different iPXE boot URL. Problem ...
user avatar
0 votes
1 answer
85 views

Cannot ping anything on intranet or internet when connected to second subnet in isc-dhcp-server

On my local network, I've got Ubuntu Server running isc-dhcp-server and named. I have a lot of devices that I've assigned static addresses to, and up until now have assigned a small range of IP ...
user avatar
2 votes
1 answer
1k views

isc-dhcp-server does not push domain-name to client

I have installed the DHCP server (isc-dhcp-server) on my Ubuntu 20.04. The client computer (also a Ubuntu 20.04 Desktop machine) gets assigned IP address, but id doesn't get the assigned domain-name (...
user avatar
  • 21
0 votes
1 answer
604 views

Server DHCPv6 with Linux Alpine

I want create a server dhcp6 with alpine I'm using Kea-dhcp6. The my file config this is: { # DHCPv6 configuration starts on the next line "Dhcp6": { # First we set up global values &...
user avatar
0 votes
1 answer
82 views

Windows AD not updating Linux DDNS in hybrid integration

I am setting up a Windows AD server, with a Linux DDNS setup. The Linux DDNS runs perfectly fine as expected. However, when I try to add the AD role to the Windows Enterprise 2019 server, the role ...
user avatar
  • 3
0 votes
0 answers
93 views

How to get custom option on client from ISC DHCP server

Over ISC-DHCP server I wanted to define a custom DHCP Option, for which I am using below config option imagefile code 224 = ip-address; subnet 192.168.29.0 netmask 255.255.255.0 { range 192.168.29.1 ...
user avatar
0 votes
1 answer
2k views

netplan - Network with DHCP configured, but no internet

I am trying to configure my Ubuntu Server 20.04 LTS to use DHCP in its network configuration. Many tutorials on the internet recommend that I create the following file with the following settings... ...
user avatar
0 votes
1 answer
2k views

Unable to add forward map SERVFAIL/REFUSED DDNS

I am using bind9 on a primary dns server with two secondary dns servers in a master/slave relationship. I am attempting to implement DDNS but seem to be running into a problem when it comes to adding ...
user avatar
  • 3
0 votes
0 answers
419 views

Block the DHCP server from broadcasting into the second ethernet interface

I have setup my DHCP server by following the instructions in https://wiki.debian.org/DHCP_Server. This all works but the issue I am having is the DHCP server is being broadcast in the main company ...
user avatar
  • 121
0 votes
0 answers
202 views

Can isc-dhcpd be configured to remove DNS records when leases expire?

I've configured my dhcp server so it can successfully add records to a private DNS zone when it issues a lease for a client. I never see it removing a lease however. Is it supposed to do so or is ...
user avatar
  • 43
0 votes
1 answer
456 views

Why is ISC DHCP server ignoring the fixed-address statement?

I want for the devices which belong to different VLANs to have different routers. For instance: The device 10.0.10.84 inside a VLAN 10.0.10.0/24 would have its router set to 10.0.10.1, whereas: The ...
user avatar
0 votes
2 answers
191 views

DHCP Server - Unable to share Internet to clients

note: I will call the server running isc-dhcp-server "DHCP-SERVER", and computer wired to my switch "DHCP-Clients" Hi, I am currently setting-up a network, and i am unable to share ...
user avatar
1 vote
1 answer
938 views

how does isc-dhcp-server start on debian 10 with systemd

I'm on a beaglebone black running a debian 10 console image. A bit of an odd setup that I have, but I need to make it run that way. The issue: isc-dhcp-server fails to start at boot, but does start ...
user avatar
1 vote
0 answers
736 views

isc-dhcp dhclient request address endless loop

when a Linux Mint 20 virtualbox VM requests the network config to the home LAN router DHCP through isc-dhcp client with the stock /etc/dhcp/dhclient.conf config file everything runs fine: (BTW 192.168....
user avatar
  • 468
0 votes
1 answer
371 views

isc-dhcp-server (dhcpd) gives old next-server in DHCP offer

I'm running isc-dhcp-server (dhpcd) version 4.4.1 on ubuntu 20.04 with a subnet configured like so, which has been working just fine. # /etc/dhcp/dhcpd.conf subnet 10.0.1.0 netmask 255.255.255.0 { ...
user avatar
  • 171
-1 votes
2 answers
980 views

dhclient is sending host-name for IPv4 but not IPv6

I am setting up a home server running Debian 10 (Buster), but I have been unable to associate the host's name with its IPv6 addresses. I have a router running OpenWRT, which is configured with dnsmasq ...
user avatar
0 votes
0 answers
510 views

ISC DHCP server - append "01" to the end of Option 43

My current Option 43 generates this hex value in DHCP Offer. See my current configuration below. f2080a0a0a0a0a141414 I need to add "01" at its very end and increase length from "08&...
user avatar
1 vote
2 answers
3k views

isc-dhcp-server: Using option dhcp-client-identifier in host declaration to identify a client

I'm using isc-dhcp-server version 4.3 (isc-dhcpd-4.3.5) as a DHCP server for my local IPv4 LAN and I'm trying to configure it to use the option dhcp-client-identifier (DHCP option 61) in a host ...
user avatar
  • 111
0 votes
1 answer
26 views

dhcpd unexpectedly destributes a useless route for another subnet as a default gateway

Our dhcpd.conf defines two subnets such like, subnet 192.168.0.0 netmask 255.255.255.0 { option routers 192.168.0.1; # internet gateway } subnet 192.168.1.0 netmask 255.255.255.0 { option ...
user avatar
  • 25
0 votes
1 answer
745 views

ISC-DHCPd how to assign different DHCP settings even if request originated from different subnet?

Network setup 10.0.1.0/28 (VLAN 1) 10.0.1.32/28 (VLAN 1) ISC-DHCPd setup subnet 10.0.1.0 netmask 255.255.255.240 { option routers 10.0.1.1; } subnet 10.0.1.32 netmask 255.255.255.240 { option ...
user avatar
0 votes
0 answers
47 views

Why does a manually deleted dhcpd lease return?

DHCPD: 4.3.6 OS: CentOS 8 I removed an entry from the dhcpd.leases file by using Webmin. It seemed to work for a time, but then the entry popped back into the file. Thinking it was a Webmin issue I ...
user avatar
0 votes
3 answers
556 views

Why can't I use IPv6 address for DHCPv4 client option 6 (DNS server)

I am trying to configure options for a DHCP network and the proprietary software (that is layered on top of ISC's DHCP server) that I am using won't allow me to put in an IPv6 address. In other ...
user avatar
  • 527
0 votes
2 answers
157 views

One DHCP server assigns IP, but another assigns other options

Is it possible to make isc-dhcp-server send dhcp options like filename, vendor-class-identifier but NOT an IP address for the client? That is, I need dhcpd to send a few options but NOT the client's ...
user avatar
  • 111
0 votes
1 answer
494 views

Why is my DHCP client w/ reserved address missing the default gateway?

I'm running isc-dhcp-server on Ubuntu 18.04. Clients without a DHCP reservation are able to get an IP address, subnet mask, default gateway and DNS servers from the pool no problem. As soon as I ...
user avatar
  • 1

1
2 3 4 5