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Questions tagged [dhcp]

DHCP is an auto configuration protocol used on IP networks.

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34 views

How to configure ipv4 Link-Local on Linux with systemd-networkd without violating RFC3927 specifications?

I'm using an embedded device with Linux 4.9 and systemd. I configured systemd-networkd in this way: [Match] Name=eth0 [Network] DHCP=v4 [DHCPv4] UseHostname=false How can I setup Link-Local only ...
0
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1answer
27 views

DHCP Server IP Conflict Detection

I am setting an Wifi Access point. A common problem about this is that router or etc. could be giving similar IP address to client devices which will cause problems. My question here is that is there ...
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2answers
53 views

Which program is releasing Linux's Dynamic IP address, if dhclient already killed?

After dhclient was killed, in short term, I didn't see the Dynamic IP lost. Then, after a weekend, the Dynamic IP address is gone. Just wonder which program released it.
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2answers
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How to configure dnsmasq to use /etc/hosts instead of “dhcp-host”?

I have been able to configure static ip for specific client in /etc/dnsmasq.conf by using "dhcp-host": http://manpages.ubuntu.com/manpages/cosmic/en/man8/dnsmasq.8.html I would like to use /etc/...
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53 views

dnsmasq: not giving name to the DHCP lease because the name exists in /etc/hosts

I am running dnsmasq on Centos 7. dnsmasq is acting both as DNS and DHCP. The DNS returns the correct ip based on the hostname. However the DHCP doesn't assign the ip address based on the /etc/hosts ...
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0answers
41 views

systemd-networkd - wlan no IPv4 address via DHCP

Setup I'm trying to set up a Wifi modem to connect to a WPA wireless network. The embedded target platform is running Linux 4.9.x, systemd-networkd (v237), systemd-resolved, and wpa_supplicant. I'...
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0answers
42 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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1answer
34 views

Debian 8(Jessie) started before DHCP server results in no network connection

Recently we got a power outage and our debian 8 Raspberry Pi did not reconnect to the internet. We noticed that our DHCP server was very slow to start > 5 min. In this time the Pi was already up and ...
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2answers
26 views

servresolv.conf become blank when system is running

I use dhcpcd to manage this file. First, start dhcpcd service, and the file has something with namesever. All things can be done correctly. But this file will become blank after a while. I try ...
0
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2answers
32 views

dhcpcd service disabled yet dhcp works

I am using Arch (Manjaro) with Gnome. My organisation recently switched to a DHCP server. So we all had to switch our computers from static to DHCP. What I noticed is that the dhcpcd service is ...
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2answers
53 views

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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0answers
21 views

Mobile Broadband for only one host

What is the easiest method to configure a mobile broadband connection in a way that: no default route is added a route to a specific host is added The connection is managed by Network Manager. The ...
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0answers
53 views

dnsmasq does not hand out IP addresses

I am trying to learn about networking, specifically, what I am currently trying is creating a private network that runs behind a NAT that connects to my main router. The way I've though of it is as ...
0
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1answer
99 views

Problem with Wpad file in Mozilla Firefox

I have this wpad.pac function FindProxyForURL(url, host) { if (isPlainHostName(host) || shExpMatch(host, "*.local") || isInNet(dnsResolve(host), "192.168.0.0", "255.255.255.0") || isInNet(...
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1answer
33 views

Change default gateway & assigned IP via script

I need some pointing in the right direction as I've tried a lot of different things over the past few days without success. I'm new to using bash and linux in general. I'm trying to detect when the ...
1
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1answer
59 views

exclude local addresses in wpad

I have a proxy Ubuntu 18.04, with squid 3128 and apache2, and I publish the auto configuration file proxy.pac with the option dhcp 252. The file has the following contents: function FindProxyForURL(...
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2answers
279 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 ...
1
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1answer
36 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 ...
3
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1answer
277 views

Permanent outgoing IP address with enabled DHCP [closed]

I have some problems making my outgoing IP address configuration permanent. I googled a lot and I do not find configuration that work for me. Assume my network is 192.168.1.0/24 with default gateway ...
0
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0answers
67 views

block LAN device by mac address using dnsmasq

My router is using dnsmasq as the dhcp server. I currently see a device identified as EPSONBBE74B which is receiving a dynamic IP address. I don't recognize that device. Nobody here can find it. I ...
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0answers
13 views

Avoid network start timeout when upping bridge on bootup

I have a laptop that has wifi and cable. The ethernet interface is called enp0s21f5 and I need to have it under a bridge to be able to connect tap/tun from kvm virtual machines. The networking is ...
1
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1answer
46 views

Is it possible to set up a secure PXE server available on the internet? [closed]

Yesterday, I successfully installed a working PXE server on a Raspberry Pi and managed to boot from it on my home server on my local network. My goal is to build a cluster with a master node hosted ...
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0answers
26 views

Share my computer's connection

I have tried several methods and none worked out for me, so I come here to ask for help. I have two network interfaces: eth0, that is connected to my office network and gets its IP from a remote DHCP ...
0
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2answers
46 views

Is there a way to cache the last IP assigned on DHCP clients and use that if the DHCP server is down?

I would like my DHCP clients (CentOS 7) cache the last IP assigned (reserved) for them and use that if the DHCP server is down. Below is the current network interface configuration of my DHCP clients:...
0
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1answer
39 views

Name or service not known in DHCP subnet [closed]

I'm trying to setup proper ip forwarding within a DHCP subnet generated through a host with two different netowrk adapters. My current situation is the following: First node with two networks ...
0
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2answers
39 views

Can't sniff / initiate DHCP renew

I am running sudo tcpdump -i enp0s31f6 -n port 67 and port 68 on one terminal and running sudo dhclient -r on another. During this, I see nothing on first terminal. What I am doing wrong? ...
0
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1answer
42 views

DHCP DNS and Domain resolution NetworkManager

My environment is following, all cabled with gigalan, all latest Debian 9, vm with virtualbox on 2 different physical hosts. A mikrotik internet router which acts as DHCPD I configured it setting ...
1
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1answer
213 views

Why do I have so many /etc/resolv.conf.dhclient-new.xxxx files?

I don't understand why I have on one machine (debian 9) so many /etc/resolv.conf.dhclient-new.xxxx files my /etc/dhcp/dhclient.conf option rfc3442-classless-static-routes code 121 = array of ...
0
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2answers
483 views

CentOS 7 DHCP Client - How to use “classless-static-routes” (“code 121”)?

According to this answer... https://unix.stackexchange.com/a/457577/61742 ... I can use the following configuration to use pushed routes from my DHCP server in my DHCP client by placing in the /etc/...
2
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0answers
235 views

How to use ISC KEA DHCP to inform “DNS” and “GATEWAY” to my DHCPv4 clients?

To illustrate I will inform the configuration of my ISC KEA DHCP (DHCPv4) and my DHCP client. Below is the configuration I am currently using for my ISC KEA DHCP (DHCPv4): $ cat /usr/local/etc/kea/...
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2answers
53 views

Why is DHCPD offering wrong lease times?

I have DHCPD on OpenBSD 5.8 running and experiencing a weird issue. I set the lease time as follows in /etc/dhcpd.conf: max-lease-time 7200; default-lease-time 7200; This should be 2 hours. When I ...
4
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3answers
710 views

Is it possible to use a single DHCP server to push completely different ranges of ip to different network interfaces in different LANs?

Is it possible to use a single DHCP server to push completely different ranges of ip to different network interfaces in different LANs? EXAMPLE: I have the Severs #1 and #2. Severs #1: A DHCP ...
2
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0answers
42 views

Is there any hook for isc-dhcp-server returning the DHCPACK to client? [closed]

I would like to run a script in the server after the isc-dhcp-server send the DHCPACK packet to client. Only now I get it solution is that running a script to retrieve the dhcp log, but it is not ...
1
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1answer
496 views

How can I use ISC KEA DHCP (DHCPv4) server to push routes to clients?

QUESTION: I have an infrastructure with 5 servers (Server #1, #2, #3, #4 and #5). I am trying to use a server (Server #5) with ISC KEA DHCP (DHCPv4) ( https://kea.isc.org/wiki ) to push routes to ...
1
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1answer
29 views

Arch i3wm valid ip, DHCP problem

related but solved by workaround: In Archlinux, it has a valid ip, but no connection could established So my arch system has gone "offline" some time ago. I didn't bother to much because I used the ...
2
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1answer
394 views

Use dnsmasq to pushing routes to my clients on a small local network

I'm trying to use dnsmasq to pushing routes to my clients on a small local network. However my clients (Server #1, #2 and #3) can not use these routes. The dnsmasq service is running and I do not ...
0
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2answers
160 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 ...
3
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1answer
181 views

new IP address whereas DHCP lease time not out

My embedded system uses systemd and gets its IP address via DHCP. The DHCP server uses lease time to give the same IP unique address to every computer on the network if lease time is respected. The ...
0
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0answers
58 views

debian stretch : how to automaticaly retry dhcp after network failure on boot

I recently had a VM that unexpectedly rebooted but the network was unavailable at that time: Jul 7 12:18:44 tuf ifup[625]: DHCPDISCOVER on ens3 to 255.255.255.255 port 67 interval 17 Jul 7 12:18:44 ...
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1answer
56 views

Linux IP resolution issue [closed]

I uploaded a new Ubuntu based MISP virtual machine on my VMWare ESX. Configured it to use DHCP and IP address 192.168.10.6 was assigned to it. I am able to get the dashboard of the MISP application ...
0
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1answer
157 views

DHCP server does not include NTP server addresses in the DHCP ACK message

I am capturing DHCP packets with tcpdump. The client sends a DHCP request asking for the DHCP configuration which contains a request for NTP servers but in the DHCP ACK message sent by the router ...
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0answers
150 views

trying to redirect all traffic with iptables but not working

I have a raspberry pi that is set up as an access point. It is NOT connected to the internet. I followed this tutorial until the section about bridging. (I don't have my raspberry pi connected to ...
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0answers
46 views

Network interface getting DHCP address while configures as static

I have a Linux server running Debian 9 with a single network interface. I have configured it to have a static ip address which worked for about a year. After a recent reboot however, it received a ...
1
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1answer
164 views

systemd-networkd dhcp_hostname option

I have configured systemd-networkd to setup my networking, I have created vlan10 and i want to client send hostname to DHCP to register in my DDNS server so question is does networkd support ...
1
vote
1answer
2k 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, ...
0
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1answer
627 views

Does openwrt have a dhcp client?

I was surprised that building a default open wrt config created an image without dhclient, After some digging we found odhcpd package for use as the dhcp server but I still can't find any package that ...
0
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2answers
184 views

Linux respond with source address of a virtual interface

Hoping this is the correct forum. I have a Linux (Centos 7) server with Quagga (for BGP) and DNSMASQ (for DHCP) installed. We are running DHCP services over BGP for redundancy. Currently, the ...
1
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1answer
495 views

UFW/IPTABLES not blocking DHCP UDP port 67?

I am running ubuntu 16.04. I have ufw installed and enabled. I also have isc-dhcp-server installed. I have not opened up UDP port 67, yet DHCP clients still seem to be able to obtain DHCP leases from ...
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0answers
97 views

How to renew the IP with dhcp client if the AP changes the IP range without disassociate the clients

We are executing the dhclient for our Wi-Fi interface. When the Wi-Fi disassociates from the AP, we have a script that renews the IP automatically from the new AP: cat dhcpaction.sh #!/bin/sh ...
0
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1answer
209 views

DHCP offer delay

Initial data: 1. Two DHCP servers: First: Description: Debian GNU/Linux 6.0.10 (squeeze) Release: 6.0.10 Codename: squeeze Second NAME="Debian GNU/Linux" VERSION_ID="8" VERSION="8 (...