Questions tagged [dhcp]

DHCP is an auto configuration protocol used on IP networks.

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Wifi connects but no internet access on Ubuntu 22.04, works fine with Windows dual boot

I have my desktop dual boot with Windows and Ubuntu 22.04. I have faced this issue before, but earlier it just went away. The issue is, my spectrum wifi connects to all devices including Windows on ...
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Multiple IPs configured, only one(first) is reachable from a remote network

Whenever a new network interface is added and configured with a new DHCP IP in Debian 12 machine, both IPs become inaccessible immediately. After restarting the machine from VMware vCenter, the ...
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Tiny and easy DHCP for standalone hosts

I am looking for a linux dhcp-server that is easy to configure and is just running when I start it on commandline - or even better keepts in foreground and quits if I Ctrl+C it. What I am not try to ...
chris01's user avatar
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systemd-networkd client-identifier DHCP Server and client DUID assignment with B.A.T.M.A.N mesh

I have 3 Linux boxes running kernel 5.15 and systemd version 250.5+. I have one of the boxes running as a B.A.T.M.A.N mesh master, with a DHCP Server managed by SystemD, and the other two are mesh ...
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cant start dhcp server

Using debian, and installed isc-dhcp-server via the following command sudo apt -y install isc-dhcp-server After agreeing to any dependencies, the follow error message was thrown Job for isc-dhcp-...
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How to launch DHCP client in Linux?

As a title, I found my wi-fi port without an IP address assigned, as follows. ifconfig wlan0 wlan0: flags=4099<UP,BROADCAST,MULTICAST> mtu 1500 ether b8:13:32:81:2c:d2 txqueuelen 1000 ...
Stan Huang at Taiwan's user avatar
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ISP Search Parameter in resolve.conf

I will try to explain this right, not a linux guru! About a week ago suddenly started getting a 401 when sending requests, seems that on our kubernetes cluster when it hits the one node that has a ...
Julie's user avatar
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What is a sane config for P2P DHCP using busybox udhcpd?

I have two computers connected directly via ethernet with one serving as a dhcp server and the other as a client my config: interface eth0 lease_file /var/lib/udhcpd/udhcpd.leases remaining no ...
qwerty_in_me's user avatar
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ifup overwrites resolv.conf incorrectly?

Debian 12.4 with networking managed by systemd networking.service, dual stack IPv4 and IPv6. I am aware of the many questions asking how to stop the system from updating resolv.conf, and this is not a ...
Ex Umbris's user avatar
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Recofiguring DNS/DHCP: a bit of advice?

I am administrating a LAN with a mix of Linux servers and Windows/OSX/Linux/other systems. A while ago I configured our DHCP- (isc-dhcpd-4.4.1) and DNS server (BIND 9.16.44-Debian) to implement DDNS, ...
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How to share my eth-wired internet from my pc to my eth-wired raspberry pi, non-wifi

I have a PC and RPI, both running debian. My PC has internet access via ethernet(not wifi), and I connect to my RPI with ssh via another ethernet from the PC to the RPI. The PC to RPI connection uses ...
raquel's user avatar
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MikroTik DHCP server sends wrong DNS server

I have a MikroTik (10.0.0.138) router, where the static DNS server 8.8.8.8 is set and DHCP is enabled. The configuration of the MikroTik is: To my understanding, when the MikroTik answers a DHCP ...
Geom's user avatar
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How do i start kea-dhcp server with multiple interfaces when first interface in the "interface" list is down

I am very new to kea-dhcp. I am trying to use kea-dhcp 2.0.1 version. below is my interface configuration mentioned in "dhcp.conf" "Dhcp4": { "interfaces-config": { ...
Pranathi's user avatar
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server does not retry dhcp after previously getting no dhcp offer

My server gets IP address from dhcp. Sometimes the dhcp server does not respond, and my server times out (no dhcp offer, sleeping) I thought, my server would re-try dhcp, but that does not happen. ...
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The best way to configure an unused Ethernet socket (RJ45)

I have a machine (QNAP TS412 ..server, no GUI, indeed no screen) with 2 Ethernet ports. Now the usual setup is I have ETH0 plugged in and getting its address via DHCP, ETH1 empty. But there 2 other ...
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Can’t get DNS IPs with NetworkManager during PXE boot

I’ve built a custom Buildroot with NetworkManager as the only networking daemon and booting my board via PXE. The problem is that /etc/resolv.conf is missing actual DNS IPs and domain. While kernel is ...
IlorDash's user avatar
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Losing IP address "DHCPv4: grace period expired"

my laptop had poor wireless signal, so I hooked it up with an ethernet cable to an access point setup in bridge mode ('client mode' it's called on the AP, I believe). It works fine, but after some ...
vicmortelmans's user avatar
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DHCP server can not receive my client in virtual interface

I'm writing a DHCP server and my own client using socket in Python3. My client: def client(self): print("DHCP client is starting...\n") dest = ('<broadcast>', ...
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systemd-networkd DHCPServer works when client is directly connected but not through unmanaged switch

I have a Linux machine running kernel version 5.15. I have systemd version 250.5+ installed and I have it configured to run a DHCP server on a physical ethernet port. I have a raspberry pi running the ...
PhilBot's user avatar
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DHCPd receives a wrong MAC-address from VirtualBox Guest

I have VM which is working with "Host-Only Adapter". I disabled VirtualBox's built-in DHCP-server. I've installed isc-dhcp-server on my hypervisor. Then I added the subnet subnet 10.10.54.0 ...
Semyon Bayandin's user avatar
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systemd-networkd 'relaytarget' not working (dhcp relay) in Debian stable 12 bookworm

my first question here. I'm currently using the 'dhcp-helper' program to do dhcp relay, works fine, but I want to switch to using the systemd-networkd 'RelayTarget' function in the *.network file. I'...
drokmed's user avatar
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Linux kernel does not accept an ICMPv6 router advertisement but sends redirect to same address instead

I'm using dhcpcd to receive ICMPv6 router advertisements from my ISP on ppp0 and everything works after a fresh boot. However, some time later, upon a disconnect and ppp0 reconnection, this does not ...
MikeP's user avatar
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Randomly loosing Internet connection after a few minutes/hours in Linux / NixOS

I have been dual-booting Linux for about three weeks now, and this issue is keeping me from fully switching because I have to reboot my computer approximately every hour. On Linux, I experience random ...
Vyxktique's user avatar
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How do I use dhclient to determine if the DHCP server can provide DNS servers?

OS is Debian 10-12. I know in some (most?) cases, a DHCP server will provide DNS servers at the same time as it leases an ip address. I would like to use dhclient to get a list of DNS servers provided ...
cat pants's user avatar
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Customized system cannot obtain dynamic IP?

I am customizing the system using version 6.4.0 of the kernel, and the file system is created using busybox. However, I don't know why enp3s0 cannot obtain an ip. It seems that using udhcpc can obtain ...
just a student's user avatar
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nftables - Setting destination MAC still sending ARP requests

I'm trying to run DHCP servers behind a private Docker bridge. I'm at a point where I can reroute the DHCPDISCOVER broadcast packets to the DHCP server behind the Docker bridge and have the DHCP ...
Synthetic Ascension's user avatar
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nftables - Forward layer 2 broadcast (DHCP) without ingress chain?

I'm currently looking into setting up DHCP servers behind a Docker bridge. My docker bridges are brought up with docker compose. I'm looking for a way to forward incoming DHCPDISCOVER requests to the ...
Synthetic Ascension's user avatar
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571 views

Reject a specific IP address from DHCP server and ask for another one

How can I configure Linux to reject a specific IP from DHCP server? I mean I do not want my lan interface to get assigned 192.168.0.12 under any circumstances. Is it possible? I have found on /etc/...
DEKKER's user avatar
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Responses to NF_STOLEN packets aren't hitting NAT rules

I'm currently working on placing DHCP servers within a Docker bridged network. To ensure packets get through I have the following: table netdev filterearly_lan10{ chain ingress { type ...
Synthetic Ascension's user avatar
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2 answers
191 views

Can netfilter act as a DHCP relay?

I'm wondering whether instead of using a DHCP relay netfilter (be that tc or nftables) can be used to route DHCP broadcast packets to a Docker container attached to a bridge. The reasoning for this is ...
Synthetic Ascension's user avatar
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Getting an interfaces `valid_lft` programmatically

iproute2 can give back an interface's valid_lft which corresponds to the dhcp lease time left. See a truncated example output hereafter: 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue ...
hbogert's user avatar
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How to make dhclient run when wlan0 is brought back up (but already has an old address)

With the following configuration on Devuan Chimaera Linux: /etc/network/interfaces auto wlan0 iface wlan0 inet dhcp pre-up /sbin/wpa_supplicant -B -Dwext -i wlan0 -c /etc/wpa_supplicant/...
fadedbee's user avatar
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Start of DHCP Client without any DHCP server delays the start of other services for a long time

On Bullseye (Debian) I have this in /var/log/syslog when no DHCP server is present on the network. Jul 10 10:45:05 localhost systemd[1]: Started DHCP Client Daemon. Jul 10 10:45:05 localhost dhcpcd[...
user2304458's user avatar
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Get prefix length of IPv6 from dhcpcd

I use dhcpcd to acquire an IPv6 address. Is there a way to find out the prefix length of the acquired IPv6 through dhcpcd? Added this to the dhcpcd.conf to get an IP for eth0 interface eth0 ipv6rs ...
user2384330's user avatar
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218 views

How to capture DHCP gateway information?

I am building a server that has multiple upstream network interfaces, each of which receives IP addresses, default routes, and other DHCP information from different routers. For my application, I need ...
fadedbee's user avatar
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DHCP Option not working

I'm using Debian with a DHCP server. I want my SIP Phone to get another VLAN and some more options, so I set the following configuration: option space OptiIpPhone code width 1 length width 1 hash size ...
Can Lotoz's user avatar
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Unable to get IPV4 with dhcpcd on Alpine in a dual stack setup

After installing dhcpcd, the machine is unable to get IPv4 from DHCP, but generate IPv6 as expected and get DHCPv6 options (like DNS, domain, etc.); the config in /etc/networking/interfaces is auto lo ...
leoniDEV's user avatar
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366 views

Why is dhclient sending a DHCPREQUEST before the lease time ends?

Jun 9 08:23:11 localhost dhclient[365]: DHCPREQUEST for 192.168.5.57 on enp4s0 to 192.168.5.254 port 67 Jun 9 08:23:17 localhost dhclient[365]: DHCPREQUEST for 192.168.5.57 on enp4s0 to 192.168.5....
rocky_alpine's user avatar
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dhcpcd deleting gateway

I'm trying to switch from DHCP to static IP by using dhcpcd. When I switch from static to DHCP I'm configuring that eth0 (which used to have the static address) will also be the one with the DHCP ...
user2384330's user avatar
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Override ISC DHCP's `option routers` with the absence of that option? [duplicate]

I was thinking I'd rather not assign my TV a default gateway, and since I use ISC DHCP 4.4 I tried to override the general subnet configuration with a host specific configuration, like this: host ...
Andreas's user avatar
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DHCP - Force install routing table to local computer

I would like to use my Ubuntu VM to act as a dhcp server and gateway for my work laptop, This laptop must connect to a Cisco anyconnect SSLVPN in order to access internal resources This VPN is not a ...
igor-root's user avatar
4 votes
1 answer
5k views

dhcpd or dhclient not found

I'm working on a custom Ubuntu 20.04 server and am trying to get a dhcp IP for it. The server has so far run on a static IP and when I run dhcp or dhclient it says dhcpd: command not found and ...
user2384330's user avatar
2 votes
1 answer
126 views

how to extract option 43 from systemd-networkd's dhcp client?

Just like how dhclient captures dhcp response and stores it in env, is there a way to capture information like option 43 from systemd-networkd's DHCP client and store it in env ? I have proxy URL ...
kpn's user avatar
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Implementing Dynamic IP Fallback Mechanism with Connman

I am working on a Debian 11-based live USB distribution that utilizes Connman for network management. However, as this distribution may run on various computers with different network interface card ...
Dani's user avatar
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Is there a way to get the dhcp Vendor Class from dnsmasq's dhcp-script

Is there a way to get the dhcp Vendor Class from dnsmasq's dhcp-script? I created a basic script that echos the args and env, and it's not there dnsmasq-script[9471]: args=old *********** 10.159.163....
Gary van der Merwe's user avatar
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Configure IPv6 DNS server via DHCP in LXC container

I have an LXC container created and started as follows: sudo lxc-create -t debian -n mylxc -- --release bullseye sudo lxc-start -n mylxc sudo lxc-attach -n mylxc On the LXC host I have a DHCP server ...
carlfriedrich's user avatar
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2 answers
165 views

How to "predict" a DHCP IP address?

Before launching a VM from my script, I need to figure out which IP address it will get. So I did: dhclient <interface> And this works, because dhclient uses the MAC address from the macvtap ...
Maestro's user avatar
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Programmatically query last DHCP lease time

I have a buildroot embedded Linux where I change the ethernet port settings (i.e. disabled, static or DHCP) from a C++ program. When switching to DHCP, it would be nice to determine when (i.e. ...
Niko O's user avatar
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3 votes
1 answer
2k views

systemd.network DUID, IAID and DHCPv4 clientIdentifier

I've set my NixOS to use: systemd-networkd: systemd.network.enable = true; and I have my interfaces configured something like that: networking { interfaces.enp5s0f0np0.useDHCP = true; ...
Mathieu Legrand's user avatar
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875 views

NetworkManager to use dhclient to reserve and set IP for wlan intf

I want to reserve and get assigned an pre-defined IP address for wlan0 interface on my client. I have set: # cat /etc/NetworkManager/conf.d/dhcp-client.conf: [main] dhcp=dhclient # cat /etc/dhcp/...
greengold's user avatar
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