Questions tagged [dhcp]

DHCP is an auto configuration protocol used on IP networks.

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31
votes
7answers
85k views

Why are my two virtual machines getting the same IP address?

I have two virtual machines both running on a Linux host (Fedora 16). I set both adapters as attached to NAT. When I boot them up they both have their default gateway set to 10.0.2.2. They also ...
24
votes
8answers
95k views

What overwrites /etc/resolv.conf on every boot?

I was given the files for a mini linux, that boots directly into firefox. It works for all it should be doing, only that I do not get an internet connection. We have 3 DNS servers in the network, ...
21
votes
6answers
159k views

Command to list assigned dhcp addresses

Is there a command I can use to ask the dhcpd server which addresses have been assigned?
20
votes
4answers
68k views

How to find out if Ubuntu is using DHCP (Ubuntu 12.04 LTS GUI)

How can I find out if my IP address is DHCP, Fixed or Dynamic? I need to tell my network administrator what the IP address is, that my Virtual Machine is using. I know the numbers, but I don't know ...
18
votes
2answers
12k views

how do you set up a linux client to use ntp information provided through dhcp?

there are so many tutorials out there explaining how to setup dhcpd server, in relation to providing ntp suggestions to dhcp clients, that I had always thought that ntp configuration was carried out ...
16
votes
2answers
44k views

Renew IP with dhclient on different interfaces

I have two interfaces on my computer, eth0 and eth1. Both subnets have a DHCP server on them. How could I use dhclient to renew IP address for both interfaces? If I do: dhclient -r && ...
15
votes
2answers
1k views

Host name changed remotely by wifi?

Am am currently visiting TU Wien and today I connected my Debian Linux laptop to their eduroam wlan using wpa_supplicant and the credentials of my home institute - as always when I am visiting another ...
13
votes
7answers
17k views

“aborting authentication by local choice (Reason: 3=DEAUTH_LEAVING)” when trying to connect to wifi

I installed Debian 9 stretch (GNOME desktop) 64-bit on my PC. My USB wireless adapter (TP-LINK TL-WN722N) was detected automatically after installing atheros firmware: apt-get install firmware-...
13
votes
2answers
85k views

Why can't I start isc-dhcp-server upon installation?

I'm following this tutorial to install Linux in a system that does not have CD reader nor USB boot capabilities. Eventually, I reached the point where I had to install isc-dhcp-server and I did, sort ...
13
votes
4answers
23k views

Docker + Bridges + DHCP

I have a lot of docker containers that I need addressable on the the same LAN as their hosts. Up until now, I have been achieving this by using setting up a bridge and manually assigning them IPs, and ...
12
votes
2answers
122k views

use dhcp on eth0 using command line

I am trying to set the eth0 interface to use dhcp to get an ipv4 address, using the command line. I can manually change the ip address using sudo ifconfig eth0 x.x.x.x netmask x.x.x.x Is there a ...
12
votes
2answers
15k views

Specifying DNS settings to override those of DHCP

Every 6 months or so I cannot access the DNS on whatever router I'm using. usually have to add the nameserver by hand to the /etc/resolv.conf file. I've tried adding Google free DNS to the file and it ...
12
votes
3answers
14k views

what is dhcpv6-client service in firewalld, and can i safely remove it?

In a CentOS 7 server, I type in firewall-cmd --list-all, and it gives me the following: public (default, active) interfaces: enp3s0 sources: services: dhcpv6-client https ssh ports: ...
12
votes
3answers
12k views

How to skip DHCP if no cable connected to ethernet in Debian

My Bananian Linux is wasting time at logon trying to get a DHCP lease for eth0 interface which is not connected. Well, the extender cable is connected to it, but nothing is on the other end. I have ...
11
votes
2answers
32k views

DHCPD ignoring my subnet declaration

eth0, my internal interface, has a static address of 10.0.0.1. I also have an interface, p4p1, acting as my external interface. If it matters, my external interface is not physically connected and ...
11
votes
3answers
22k views

Location of dhclient.conf

I need to check the client DHCP settings, which I expect to be in the file /etc/dhcp/dhclient.conf, but there is no such files there. What is the location of this file in RHEL 6, on 64 bit?
10
votes
1answer
12k views

what is “rfc3442-classless-static-routes” in /etc/dhcp/dhclient.conf

I am trying to debug DHCP on my laptop (I am using dhcping and dhcdump to see what the DHCP server sends back). Following is my /etc/dhcp/dhclient.conf. option rfc3442-classless-static-routes code ...
10
votes
4answers
36k views

Check my DHCP lease?

Is there a way to show my current (client) DHCP lease? Or even better - retrieve all options/infos sent with DHCPACK?
10
votes
2answers
11k views

dhcpcd can't startup at boot

when I run dhcpcd after boot everything works fine but when I try to add it to auto start systemctl enable dhcpcd@eth0.service, after each boot it's inactive dhcpcd@eth0.service loaded ...
10
votes
2answers
18k views

Force dhcp client to get a new lease

I have a linux DHCP server running on my network. I recently found out that I can assign specific IP addresses to clients based on their MAC address by modifying the dhcpd.conf file. Now is there ...
10
votes
1answer
11k views

How to fix “deauthentication by local choice”?

I built an embedded Linux using Buildroot and I have some trouble to stay connected to my AP. Cannot get an IP address more than once. I use wpa_supplicant to connect to my AP using WPA2-PSK. It ...
9
votes
1answer
8k views

Is there anything wrong with using dnsmasq as a dhcp server instead of isc-dhcp-server?

So I've configured my home connections to work with dnsmasq since it bundles a dhcp server with it and is quite nice to set up. There is another package - isc-dhcp-... that also does this and perhaps ...
9
votes
6answers
77k views

Debian dhcpd “No subnet declaration for eth0”

I am trying to set up a pxe boot server on a Debian 6.0.3 Squeeze machine that gives images of PLoP Linux. I was following a this tutorial. When I try to start dhcpd (from package dhcp3-server), I ...
8
votes
2answers
88k views

Setup static IP in redhat 6

I installed Redhat 6 x86_64. I am using the Network connection screen to set a static IP address like below (I want two PC's in my house to see each other: one Redhat PC and one Mac) 192.168.0.5 ...
8
votes
4answers
15k views

DHCPv6 prefix delegation server for linux?

What linux DHCPv6 client can I set up so it requests a prefix on one interface and then on all the other interfaces it will give out addresses (or if requested, a smaller prefix delegation)? It would ...
8
votes
2answers
38k views

How to auto generate resolv.conf on Centos 6.5

I just installed CentOS 6.5 and configured the following files: /etc/sysconfig/network-scripts/ifcfg-eth0 DEVICE=eth0 HWADDR=aa:bb:dd:dd:ee:ff TYPE=Ethernet UUID=adfddfaf-9sda-adse-dfs4-asdfsdfdfg97 ...
8
votes
3answers
6k views

Bridge does not get IP via DHCP at boot

I'm running CentOS 7. I'm not running NetworkManager, and I've actually uninstalled it. My system is supposed to acquire an IPv4 address via DHCP on br0 at boot. Howver, when I log in, it has no ...
7
votes
5answers
16k views

How to overcome libc resolver limitation of maximum 3 nameservers?

Suppose I work in environment with number of domain changes and slow propagation. I want to test domain configuration immediately after setting change but the propagation is slow. So I want to add ...
7
votes
3answers
4k views

How do I get NetworkManager to keep the same IP?

The DHCP-provided IP on my laptop changes periodically. It runs CentOS 6.5 and uses NetworkManager. My desktop, running Sabayon, on the same network, does not have this problem. How can I get ...
7
votes
2answers
6k views

Why are my cloned linux VMs fighting for the same IP

I've cloned two vSphere VMs off of an Ubuntu 17.10 template. After boot, they both claim the same IP and fight for it (ssh connections break off as the IP switches between them). The hostnames and ...
7
votes
3answers
4k views

Change default search name

My Ubuntu12 server VM is receiving its IP address from an DHCP server (actually my WLAN router called Fritz Box). Hence all domain names are resolved to machinename.fritz.box. The reason seems to be ...
7
votes
4answers
8k views

All commands that should be used to connect to wifi in command line

I would like to switch from gnome to awesome and I would like to connect my wifi network in command line (instead of using gnome tools). So, I searched on the internet and found approximatively the ...
7
votes
4answers
12k views

Maintaining `/etc/hosts` for hosts on DHCP

On my local DHCP network I have different PC's that I need to access remotely. Problem is that their IP's change. Sometimes I plug my laptop and netbook into other people's DHCP networks. My current ...
7
votes
2answers
12k views

How do I set dhclient debug info on?

On a FreeBSD computer Is there a DHCP client log that I could use to debug a DHCP issue? Can I set a debug param to get more information from the dhclient? UPDATE #1 I found a lead on this article ...
7
votes
1answer
13k views

QEMU-KVM and internal DHCP server

I have set up a few soon-to-be production VMs running on QEMU-KVM on Ubuntu 10.04 LTS. As for networking, I chose the "NAT" option in Virt-Manager and each VM now gets an IP address 192.168.122.x ...
7
votes
1answer
6k views

avahi-daemon withdraws IP address from my network interface

I am running an Arch Linux server in my local network. It has avahi-daemon running on it to advertise some services (like a print server). It has happened for the second time now that my server was ...
7
votes
2answers
2k views

Strip specific option from a response in dhclient

I aim to prohibit dhclient from updating my NTP config with servers received via DHCP, as it is the default on Debian/Ubuntu. However, my DHCP server ignores the list of requested options (from the ...
6
votes
1answer
39k views

Append DNS suffixes to /etc/resolv.conf

Is it possible, and how do I configure CentOS 6.6 so that /etc/resolv.conf will obtain its configuration via DHCP, but will also have additional domain names added to the search line? Bonus points if ...
6
votes
9answers
20k views

File /etc/resolv.conf deleted on every reboot, why or what?

I am having an issue where DHCP (I though as I read in other similar topics) is clearing the /etc/resolv.conf file on each boot. I am not sure about how to deal with this since the post I have found (...
6
votes
2answers
12k views

Get client hostnames from DHCP

I have a voyage 2.6.38 machine running DNSMASQ for a DHCP server and I would like to get the hostnames of the clients that acquire DHCP leases. How would I go about doing this?
6
votes
1answer
3k views

Set hostname on first boot before network.service

I have a firstboot.service that, from a stock OS image creates a unique hostname based on the MAC of the primary ethernet adapter. It runs as expected during boot but the hostname that gets ...
6
votes
3answers
4k views

How do you prevent a DHCP release during shutdown?

I am currently using Ubuntu 14.04, but expect this to be applicable for different distros. I would like to prevent a DHCP release during shutdown, and opt for either the lease to expire or for a DHCP ...
6
votes
1answer
5k views

Two IP addresses assigned to the same machine?

I seem to be using two IP addresses on my PC. I use DHCP to get an IP address and then I statically set an IP address and activate it. ifconfig says that I am using the address given by DHCP but I am ...
6
votes
3answers
7k views

How to force network.target to wait for DHCP with systemd-networkd?

I'm using systemd-networkd to configure my interfaces: [Match] Name=enp3s0 [Network] DHCP=v4 It works quite well except that at boot, some services are not waiting for DHCP to finish. For ...
6
votes
2answers
2k views

Prevent dhcpcd from setting hostname

How to prevent dhcpcd from setting hostname got from server? Change of it breaks a lot of things (including X session). My current distribution is Gentoo, init system is systemd and dhcpcd is spawn ...
6
votes
1answer
11k views

isc-dhcp-server fails to start at boot

I have been running the isc-dhcp-server fine for quite a while. A few days back after an update, it fails to start. I found a few more people reporting similar problems but that was from 2009. I was ...
6
votes
2answers
3k views

How to setup wireless AP with two wifi cards and ethernet as WAN on debian?

I'm trying to build wireless AP with 2 Atheros cards (AR5413 / AR5414 both), and one ethernet card to act as WAN. I am also having doubts if I should use ath5k or madwifi drivers. I've tried both ...
6
votes
1answer
2k views

How to force Debian to wait for DHCP

I am running Debian squeeze in a virtual machine (VirtualBox). The machine has two interfaces: eth0 in "Host-only" mode so that the machine is accessible from the outside; and eth1 in "NAT" mode so ...
5
votes
2answers
1k views

How to send an alert if the DHCP range is exceeded, using shell script?

I've installed and configured a DHCP server on CentOS 6.5. I've also added a subnet to the dhcpd.conf file as follows: subnet 192.168.1.0 netmask 255.255.255.0 { option domain-name-servers 192.168....
5
votes
1answer
15k views

How to get Pi-Hole to work with IPv6?

At home I have installed Pi-Hole on a Fedora 28 machine, and it is now working properly serving IPv4 addresses via DHCP, acting as the DNS server, and blocking IPv4 addresses as appropriate. However, ...