Questions tagged [dhcp]

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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Debian 10 Buster can't renew DHCP as client, when IPv6 is disabled

After I upgraded Debian 9 to 10 Buster server lost network connection after 24 hours since reboot, I think problem is it can't renew IP address from DHCP server. In /var/lib/dhcp I see the file ...
Roman_G's user avatar
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DHCP Server Not Offering to PXE Client

DHCP Server Not Offering to PXE Client BACKGROUND: I'm in the process of adding PXE services to an existing SCCM 2007 server. The SCCM server is separate from the DHCP server (Server 2008 x86) and ...
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BIND: DNS failover and high availability with dynamic updates

I am trying to design a system with 2 servers that act as both DHCP and DNS servers with dynamic updates. I am using ISC DHCP and BIND9. It looks like this. Server1 - DHCP primary and DNS master. IP ...
Ruben Tsirunyan's user avatar
5 votes
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How can I identify a rogue IPv6 DHCP server on my LAN?

This will be kind of a long post, but I want to give complete information. I have a home/business LAN with isc-dhcp-server running an ipv4 dhcp server and bind as a DNS server running on an ubuntu ...
surfrock66's user avatar
4 votes
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7k views

Windows DHCP Server not responding to relay requests

I have a Windows Server 2016 (Datacenter Core) running DHCP server role which is not responding to DHCP requests which come from a DHCP relay but is responding to DHCP requests on the local network. ...
digitalPhonix's user avatar
4 votes
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567 views

DHCP Server Listing Host as "BAD_ADDRESS" and not Registering DNS

Question Why is DHCP showing "BAD_ADDR", why does it think there is a Conflict, and why can't the host register its DNS name? Devices: DHCP Server = Server 2012 on bare metal. Also running DNS. ...
Copy Run Start's user avatar
4 votes
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Cannot renew DHCPV6 lease in SLES12

I need to renew the lease of a certain SLES12 box. The machine is configured to use IPv6 only and so far I have tried the following: From here: dhclient6 -r -v eth0 && rm /var/lib/dhcp6/...
Ivan Kalchev's user avatar
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VLAN ID over DHCP for Management Interface of Fortinet FortiAP

When configuring the FortiAP device it's desirable to configure the VLAN ID for the tagged management network. Accordingly to the manual it's possible to do so by "telnetting" to the FortiAP device ...
Vinícius Ferrão's user avatar
4 votes
2 answers
2k views

Prevent Windows Server 2012 from using DHCP-provided default gateway?

How can I prevent Windows Server 2012's local network connection from using the default gateway provided by a DHCP server? I do not control the DHCP server so the solution must be implemented on the ...
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4 votes
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DHCP fault tolerant servers: Split pool or failover?

I need to replace an aging DHCP server by a fault tolerant solution. I consider using the ISC dhcp server solution which can be setup either as split servers serving non-overlapping ip ranges or as a ...
ripat's user avatar
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vmware DNS in host-only configuration

I want to connect a Linux VM running in VMWare on a Windows 7 laptop to an enterprise network using host-only configuration. I was able to setup bidirectional routing between "host-only" VMWare ...
nponeccop's user avatar
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Windows 7. DHCP option 121 works partially. But it working fine for XP and Mac OS X

I've setup pptp server on cisco router today. The remote client IP addresses are assigned on this cisco router by DHCP. Also I set up option 249 and 121 to provide classless routing for my VPN clients....
pchel's user avatar
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3 votes
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dnsmasq: How to set alias domain / multiple DNS suffixes for local hostname resolution?

Is it possible to set multiple search domains via dnsmasq/DHCP? Due to some migration, I need multiple clients to be able to: ping server.old-domain ping server.new-domain # both should work, .old-...
ramo's user avatar
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3 votes
2 answers
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Is it possible to have name-resolution from Fortigate and local DNS server?

Can you advise on moving to a hybrid DNS? Currently, all our LAN machines receive their IP address from our Fortigate 60D (each machine is either allocated an IP address from the Fortigate DHCP, or ...
boardrider's user avatar
3 votes
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2k views

DHCP Server not responding to relayed DHCP DISCOVER

I'm currently segmenting our network in various subnets. We already have a DHCP server as a part of our Active Directory (Server 2012). I want to use this server for all subnets so I need to work with ...
davidb's user avatar
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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: #...
Chuck's user avatar
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Did I cause this DHCP failure?

I asked this here, it was requested that I move it to this forum instead. I have a question that I need some counsel on concerning DHCP and what may happen in a certain situation. I have a case ...
Sabre's user avatar
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Assign a public ip to openvpn client

For learning purposes, I'm trying to set up openvpn server, so that each connected client would get a unique public ip address. I have a vps server and I ordered extra 8 static ips and they are ...
Moataz Elmasry's user avatar
3 votes
1 answer
345 views

How did AirPort's DHCP "Welcome Message" work?

I remember that Apple's AirPort base stations used to have a DHCP "Welcome Message" feature, that would display a custom pop-up dialog when computers connected to the network. How was this ...
Trevor Johns's user avatar
3 votes
1 answer
257 views

Reaching out DHCP relayed hosts

I have one primary server (DHCP) and one secondary (DHCP-RELAY). Majority of hosts are served from primary (wirelessly), however there are a few (wired ones) which get their IPs from secondary. ...
NarūnasK's user avatar
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ISC DHCPD IPv6 for multiple interfaces

I want to assign multiple IPv6 to a server with multiple NIC. As IPv6 RFC defines, each server has a unique DUID that can have one of the 3 formats (LL, LLT or enterprise). And each NIC has an IAID. ...
Seoman's user avatar
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3 votes
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DHCP Server Issuing NAK when servicing multiple subnets

We currently have 3 VLANs setup in our network. On our DHCP server (Windows 2008) we have 3 scopes created for the 3 separate subnets. Our clients can't seem to pull addresses on the subnets, except ...
SElaschuk's user avatar
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How to config libvirt network setting about disabling dnsmasq "except-interface=lo"?

Here is the thing. My VMs run with libvirt and use default network libvirt-provide, and I've mad each VM registers its hostname to dnsmasq set by libvirt. so I want to look up its hostname for ...
Chen OT's user avatar
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1 answer
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Client see Windows Deployment Services but still get "selected boot device failed" error

Like the title says I can't Windows Deployment Services working. The client laptop has an ethernet IP address of 10.0.4.94. On the secondary DHCP server I've set option 60 to PXEClient, option 66 to ...
David Vasandani's user avatar
3 votes
1 answer
7k views

Use Framed-IP-Address RADIUS attribute for IP allocation with DHCP on Windows Server 2012R2

I have configured a DHCP server on Windows Server with an NPS Policy, connected to a FreeRADIUS2 server running on pfSense. Authentication is based on MAC address. If MAC address is not present in ...
ju71's user avatar
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2 votes
0 answers
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DHCP unicast packets processing in Linux

I'm trying to catch and process (in 3rd party analytics app) DHCP packets from ERSPAN session, but cannot do this. There is PHY interface which receive ERSPAN traffic and erspan-type interface to get ...
Volodymyr Litovka's user avatar
2 votes
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210 views

NTP Server Precedence using systemd-timesyncd

I'm looking for documentation which specifies the precedence / priority of NTP servers (ubuntu 20.04). I am using timesyncd which has the ntp.ubuntu server But when connecting to the network via DHCP ...
Jake Baker's user avatar
2 votes
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2k views

Why is my systemd-networkd not aquiring an IP address via DHCP?

On my notebook running Gentoo, I set up the following things: Kernel with all necessary settings and modules WPA_Supplicant Systemd Systemd-Networkd Almost everything works as expected, the ...
ahuemmer's user avatar
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DHCP searching wrong network

I have a stand-alone device with no console. It's searching for DHCP address on 192.168.1.1/24 while my network router serves DHCP for 192.168.0.1/24. Thus, the device is not getting assigned an IP ...
usao's user avatar
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2 votes
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3k views

dnsmasq dhcp ignoring dhcp-host definitions

I am currently puzzled by the dnsmasq configuration, and I hope someone here can help me... I've setup successfully the DHCP-Server with dnsmasq, and I've tried to include some static Host ...
Martin's user avatar
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2 votes
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Request an address from a range of IP-addresses using dhclient dhcp-requested-address

I am in a situation where I need myDevice (ubuntu), when connected to router, to have any IP address in the range of 192.168.1.20 to 192.168.1.40. I am aware that adding the line send dhcp-...
daedalus_hamlet's user avatar
2 votes
0 answers
135 views

DCHP server on virtual machine in HNVv1 virtual network

I've got a virtual machine with Windows Server 2016 Datacenter, Hyper-V nested virtualization on the host operating system switched on for this virtual machine and Hyper-V role installed on it. PS C:\...
symon's user avatar
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2 votes
0 answers
3k views

Dynamic DNS (DDNS) updates from dnsmasq for use with bind9

Previously I ran dnsmasq on an OpenWRT to provide DNS and DHCP functionality, because this is, what it is intended for. I want to offload the DNS part to an already configured bind9 (running on Ubuntu)...
zeus's user avatar
  • 21
2 votes
0 answers
984 views

Clear routes from DHCP option 121

I have 3 subnets 192.168.10.0/24 192.168.103.0/24 192.168.2.0/24 Most of them can route to each other via static routes defined in their respective default gateways. However due to some ...
Qowy's user avatar
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2 votes
0 answers
536 views

DHCP client doesn't get address

I'm trying to use a Phytron MCC-1 motor controller which gets its IP only via DHCP (no manual setting). I setup isc-dhcp-server on ubuntu as such: # /etc/dhcp/dhcpd.conf option domain-name "example....
dargaud's user avatar
  • 203
2 votes
1 answer
289 views

How to share VPN and DHCP server across multiple hosts?

I need to set up a small computer network for what is effectively a satellite office for a business. The small network consists of several workstations and a server. The server machine has two ...
tj94's user avatar
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2 votes
0 answers
640 views

Weird answer of linux DHCP server to gratitious ARP causes DHCP failure

This is a problem, that I ran into recently on a quite heavily configured linux server. This machine runs Samba as an Active Directory Domain Controller, a mail server, a web server, two virtual ...
Kai Petzke's user avatar
2 votes
0 answers
3k views

DHCP Server: Missing Addresses and how to free them

Our DHCP Server, running on a Windows Server 2012 R2 Data Center, shows that we have 241 addresses total with 220 (91%) in use, 21 available. If I go to the Address Leases node and count all IP ...
Sarah Weinberger's user avatar
2 votes
0 answers
538 views

Docker: Assigning IPs to containers using a DHCP server

I want to get docker to assign IPs to my containers using a DHCP server, so that they are kind of static based on MACs. From my preliminary research, it looks like I can use macvlan networks to create ...
Megh Parikh's user avatar
2 votes
0 answers
1k views

How to configure QEMU DHCP and DNS for VMs?

I am trying to configure a QEMU setup with several VMs that talk to each other (e.g. a LDAP server on a VM that provides SSH authentication to other internal VMs). All these VMs are user mode and ...
Tiago Antao's user avatar
2 votes
0 answers
164 views

ISC DHCP (Infoblox) takes 30+ seconds to respond to DISCOVERS

Client's DISCOVER packets reach the Infoblox DHCP server through DHCP relays, but Infoblox doesn't seem to be responding. I checked the pcap taken from the DHCP server, I can see there is 3 DISCOVERS ...
Vignesh SP's user avatar
2 votes
0 answers
141 views

Fedora 26 graphical login starts before network fully running

I am creating a Fedora 26 image that is going to run on around 100 machines in a closed environment. These machines will be connecting to two servers, one for NFS, the other for web services. The web ...
astoman's user avatar
  • 21
2 votes
0 answers
1k views

How to configure Juniper SSG5 with VLANs and DHCP

I just purchased a used SSG5, upgraded the firmware, and now I'd like to set it up as my Firewall/DHCP/VPN. I'm new to Juniper, so please forgive any blatant missteps in terminology. I am familiar ...
juan julio's user avatar
2 votes
1 answer
1k views

DHCP server is not selecting IPs inside of the specified range

I have my DHCP server which I specificaly set the ip range to be between: 10.53.70.100 -- 10.53.70.200 but there are sometimes I get IPs outside from this range. For example, the last server I created ...
VaTo's user avatar
  • 231
2 votes
0 answers
466 views

Does "broadcast-address" needs to be within defined subnet in dhcpd.conf?

Ideally, broadcast address should be last address of defined subnet.But I don't see dhcp server enforces such restriction.A brodcast-address defined outside subnet in dhcpd.conf is accepted by dhcp ...
user2589882's user avatar
2 votes
2 answers
1k views

Why does my Ubuntu virtual machine hosted in Hyper-V power on with a date in the future?

I have several Ubuntu virtual machine running within a Hyper-V server. The server is a Windows 2012r2 machine. The Ubuntu VMs are either Ubuntu 14.04 or Ubuntu 16.04 (the current LTS releases). ...
TafT's user avatar
  • 253
2 votes
0 answers
813 views

Interface being deleted

I have a cluster consisting of CentOS6.5 and CentOS7 virtual machines. I've come across an issue where the network interface, eth0, is being deleted for reasons unknown and I'm looking for help on how ...
korre's user avatar
  • 21
2 votes
0 answers
2k views

DHCP client not getting IPv4 address from a DHCP server

I configured a DHCP server on a VM in VirtualBox. This machine has 2 network adapters, enp0s3 - NAT (from where I have my network connection) and enp0s8 - Internal Network (intnet). DHCP server is ...
Alex V's user avatar
  • 21
2 votes
0 answers
183 views

Abnormal DHCP Android device traffic cannot be identified

Hi Serverfault community members. I've been trying to identify the source of an abnormal broadcast traffic generated by some Samsung Android devices with no success, so I ask for your help. I have ...
Dago Pacheco's user avatar
2 votes
1 answer
449 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, ...
vambo's user avatar
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