Questions tagged [dhcp]

DHCP is an auto configuration protocol used on IP networks.

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dhclient.conf modifications do not change resolv.conf

When I modify my /etc/dhcp/dhclient.conf with prepended nameservers, after a network manager restart, the generated resolv.conf file does not contains these servers. I'm working on Kali Linux. Here ...
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8answers
102k 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, ...
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1answer
30 views

How to automatically change DNS nameserver

My ISP's DNS server has problems resolving lots of important websites like google, github, gmail etc. As a hack I manually edited the /etc/resolv.conf file to Google's 8.8.8.8. But the changed file ...
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1answer
23 views

dhcpcd dhcpv6 times out after Router Advertise, never sends a DHCPv6 Request

I use a linux host as an IPv4 router and looked into enabling IPv6 (it's the future, I'm told). I already use dhcpcd as a dhcpv4 client to get an address from my ISP, so I figured I'd use it for ...
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2answers
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How to determine IP address of guest operating system in qemu?

After I boot a Windows XP in qemu it gets an IP assigned from DHCP server. My question is - how do I determine the IP that Windows XP got assigned, so that I can connect to Windows XP? Here are more ...
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4answers
3k views

Systemd-networkd: Run script after DHCP client aqcuires new address

I am on ubuntu 18.04 server. I need to run a script that updates an IP address on CloudFlare (kind of DynDNS script). In previous versions I could do this with a DHCLIENT exit hooks for the interface ...
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Run script on obtaining custom vendor option in Stateless DHCPv6 client

I am using Ubuntu and this question is regarding DHCPv6. After obtaining RA (router advertisement) with O-bit ("Other configuration" flag) set to 1, an information-request is sent by the client. ...
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2answers
47 views

Is DHCP client of any use on my desktop computer?

Is DHCP client of any use on my desktop computer? I use my computer mainly for office purposes (web browsing/media consuming/libre office). As I am setting up some firewall rules, I wish to restrict ...
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Passthrough of OpenVPN clients to local network

Ahoy friends. Unfortunately i don't have that much knowledge about OpenVPN but at least i want to try to get my idea working. Currently i'm using a VoIP device connected to my local area network, and ...
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1answer
17 views

Always trying to connect to wifi, but never connects, ping 8.8.8.8 results in “connect: network is unreachable”

I just bought a Raspberry Pi 4 which uses linux as its operating system. I was just trying to browse the internet using my phone hotspot when the connection suddenly drops, I can't access any other ...
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How to setup a network card IP to be dynamic first DHCP, but to have static IP as fallback in CentOS/RHEL?

In CentOS7/RHEL7, ideally already via a kickstart configuration a network card should be setup in a way to attempt getting dynamic IPv4 address via DHCP and if no DHCP lease is available (after some ...
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1answer
87 views

Configure ntpd to find local NTP server(s)

I'm currently designing a system (a physical system that can be used where ever) and have run into the issue that on some networks internet NTP servers can be blocked (by a firewall). In those cases ...
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1answer
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Where is DHCP data stored on OpenBSD?

I'm currently testing with some DHCP and I'm wondering how I can verify if options like "option host-name" or "option domain-name-servers" really worked on the client machine (OBSD 6.6). Where does it ...
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4answers
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DHCP and read-only root filesystem

When doing ifup wlan0 on a system with / mounted as read-only (embedded computer), I get this error: Failed to connect to non-global ctrl_ifname: wlan0 error: Read-only file system Internet Systems ...
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1answer
2k views

start dhcpcd on specific interfaces only explicitly

On my machine I have multiple interfaces which often have a dhcp server running. I now want to react differently on various 'setups': when there is wifi, use wifi when there is ethernet, use ethernet ...
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3answers
47 views

Setup static IP address for 1 machine and DHCP for other

I'm using my Laptop on several networks. When I'm at home or at the office I occasionally want to connect with my phone to a server running on my laptop (say MPD, ssh, transmission). The problem I'm ...
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1answer
160 views

How to make dhcpd recognize a new interface without restart

I'm working on automatizated virtualization but currently i'm stuck with setting up the DHCP server. The problem is, every time i create a virtual machine, i have to restart the daemon to register the ...
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1answer
39 views

Networking - VLAN & Router Linux

I have a setup with 1 Debian router + 1 Debian DHCP Server. I need to create multiple VLAN on my DHCP server. From my DHCP server I have internet access. I managed to create and set up my VLANs and ...
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1answer
9k views

How do i check if DHCP is enabled?

I have a VM running Debian 9 and the latest version of VirtualBox. I have VirtualBox configured to use the bridged adapter and it was working fine yesterday. But when I came and got on it this morning....
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Request a specific HOSTNAME(OPTION 12) from specific ip from DHCP server

Is it possible to request the hostname (OPTION 12) from a specific ip without having to intercept the DHCPREQUEST (and therefore wait for the device to disconnect?)
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1answer
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KVM, qemu, libvirt no DHCP on bridge

After I restart firewall on the host machine, I no longer get DHCP on guests until I restart libvirtd.service I am providing two network captures, one before restarting FW on the host (dhcp_ok.pcap) ...
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Dhcpdump problem redirect output

I noticed that when I run the dhcpdump command everything works correctly (obviously) and everything is shown on the screen. But if I try to redirect the output to a file, for the first few minutes ...
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1answer
6k views

Cannot get IP address from WiFi access point (hostapd) with DHCP (dnsmasq) bridged with two ethernet adapters (bridge-utils)

My Android phone is trying to get DHCP address through WiFi connection, but fails. Obviously, I might have messed up something in my settings because I couldn't find a complete guide which would let ...
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0answers
58 views

Can't Enable isc-dhcp-server on boot

I've installed DHCP Server on Proxmox/Debian and did the required configuration for it to be ready for use. However when I run the command root@debian:~# systemctl enable isc-dhcp-server isc-dhcp-...
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Ubuntu Desktop broadcasts hostname, but Ubuntu Server does not

In short, I have four VM's running on Hyper-V as a Docker/Kubernetes Cluster. The Master is an Ubuntu Desktop 19.4 instance. The Nodes are all Ubuntu Server 19.4. All the images have exactly the ...
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2answers
2k views

How to check out DHCP lease time on OpenSUSE provided by DHCP server

I need to check out DHCP lease time on OpenSUSE Leap 42.2, I tried these, but they didn't work: ~> less /etc/dhclient.conf ~> sudo less /var/lib/dhcp/dhclient.leases # ls -a /var/lib/...
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2answers
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dhclient command does not allocate ip address to my interface

So I was trying to access a website through my browser but I couldn't. So I issued the ifconfig command to see if there was something wrong with the IP address I noticed that the interface enp0s3 ...
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2answers
1k views

resolv.conf rewritten by DHCP even after setting the NIC as static, RHEL 7

I am facing a strange situation on all my RHEL 7 servers. All the RHEL 7 VMs are provisioned using a provisioning tool which connects to a VM offering a DHCP IP, once provisioning is complete we run a ...
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7answers
18k 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-...
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2answers
2k views

Why are routes set in /etc/network/interfaces not added when the interface comes up?

Here is my interfaces file: auto lo iface lo inet loopback auto eth0 iface eth0 inet dhcp auto eth0:0 iface eth0:0 inet static address 10.20.8.231 netmask 255.255.255.0 ...
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1answer
17 views

Prevent DHCP queries for a particular interface

I have a laptop with a Wi-Fi card and an Ethernet card, both connected to the same network. Despite my best efforts to disable the Wi-Fi, my system keeps trying to obtain an address for it, not only ...
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1answer
92 views

udhcpc: DHCP option 66 variable tftp contains “bad” if DHCP server provides IP address instead of hostname

I am working on an embedded Linux which uses BusyBox and udhcpc (part of BusyBox) as its DHCP client. If I configure the DHCP server to deliver an FTP server in the DHCP option 66 everything is fine (...
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3answers
8k 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 ...
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1answer
5k views

How to debug DHCP timeout on WiFi connect

I've recently moved to a place with public wifi (so I don't have access to the router or their DHCP config), and am running into issues connecting with my Arch laptop. I've tried using both ...
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1answer
101 views

Disabling automatic default route from dhcp server

Hi I'm trying to configure my Raspberry PI to work as a dhcp server. Idea is that through eth0 interface I will connect switch, to which I can connect other devices. But I still want to keep ssh and ...
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0answers
40 views

Issue with Internet connection on fresh Arch install

I am trying to connect to the Internet via Ethernet on a freshly installed Arch Linux system. I am following this YouTube tutorial. Once I got to the Internet part, I started having issues. I cannot ...
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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 ...
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0answers
8 views

Why ISC KEA DHCP (DHCPv4) does not release an IP that has heen reserved and now released?

I reserved an IP ("reservations") for a MAC ("hw-address"). That MAC was removed from my subnet and the IP was reserved for another MAC. That another MAC cannot "get" the IP that is now reserved for ...
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0answers
53 views

Ubuntu Server connected to 2 switches can't ping outside local network

To summarize, I just want to ping from the server. Dell Server Running Ubuntu Bionic Motherboard with 2x10Gb port => Connected to LAN switch Extra Network Card with 2x1Gb port => Connected to ...
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2answers
2k views

LXC ip allocation using DHCP

I'm trying to set up DHCP for my lxcontainers without using lxc-net. The reason for this decision is that I'd like to place my containers in different networks, such that they are unable to talk to ...
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2answers
1k views

wpa_supplicant doesn't get new IP when re-associate?

I am struggling to setup my wlan so it can re-associate to another hotspot and renew its IP automatically. I have found a similar question but nobody responded. I am using Debian stretch. The first ...
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2answers
2k views

NFS over TCP not available from (My server ip) - network is unreachable & permission denied

I am trying to boot linux mint from a server I set up in virtualbox. Server is running in linux mint, and the client that I'm testing on (also virtualbox) is disk-less and booting over network. After ...
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2answers
2k views

When no dhcp server answer, how can I force dhclient to use the static lease from dhclient.conf instead of a previous dhcp lease?

I have a piece of equipment I would like to default to a specific IP address when no dhcp servers are available. I have set the following static lease in /etc/dhcp/dhclient.conf: timeout 30; lease {...
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0answers
14 views

Keeping isc-dhcp-server running even if there's no subnet

I use isc-dhcp-server to provide IP addresses to some instruments that connect intermittently via a USB-to-Ethernet adapter, addresses in the 192.168.1.0/24 range. If the adapter is not connected when ...
0
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1answer
130 views

Theoretical: TAP interface w/ WIFI parent interface

I'm trying to create multiple Linux TAP interfaces and allow them to send/receive packets over a single WIFI adapter. For all intents and purposes I'd like the TAP interfaces to act as full fledged ...
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1answer
105 views

How to verify static LAN IP assignment to USB0

A Raspberry Pi 3B+ is configured with Raspbian with a working wifi: pinned to a static LAN IP address Per the procedure: a static IP 192.168.42.42 assigned to the rPi's USB0 interface. Append: ...
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0answers
19 views

Can I configure a manual link-only IP address?

I've recently purchased an unmanaged switch, and I'd like to have a number of devices wired to it via ethernet, communicating solely with one another (the use case is "wifi for the outside world, ...
2
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0answers
642 views

How to flush all the DHCP leases with virsh. So all not just one with net-update default delete ip-dhcp-host

OS: Fedora 28 KVM So I am trying to delete all the dhcp leases with virsh, so all of them at once not one by one or any one in particular. I know that you can use net-update default delete ip-dhcp-...
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2answers
3k views

PXE boot chaining to hardcoded TFTP server?

My existing network environment provides the following: DHCP server that sends PXE clients to a particular TFTP server TFTP server with SYSLINUX "pxelinux.0" file for booting The SYSLINUX ...
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1answer
98 views

DHCP lease table in router shows weird entries when connected to Linux server

I have a domestic server where a MitraStar ADSL router is connected to a bunch of mobile devices plus two desktop machines (one Linux and one Windows) connected by Ethernet cables. IP address 192.168....

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