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Questions tagged [dhclient]

dhclient is the DHCP client for Linux and UNIX, created by the Internet Software Consortium. It is used to configure network interfaces using DHCP or BOOTP protocol, or can be used to assign static configurations.

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Shouldn't dhclient confirm its lease after a carrier loss?

I'm investigating an issue with a Ubuntu server acting as the Internet gateway for a branch office stopped working after being switched to a new Internet connection. The IP address on the external ...
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20 views

AWS time traveling issues with dhclient

I am a QA software engineer working on integration tests that require changes on the system clock to simulate the pass of the time. When running those tests on AWS EC2 instances I got unexpected ...
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2 votes
1 answer
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My network interface changes names, so DHCP / dhclient cannot operate on it

On some ArchLinux servers I've switched from dhcpcd to dhclient, but the servers are not receiving IP. Upon inspection with journalctl I see that, on all occasions the IP was not received, dhclient ...
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2 votes
1 answer
772 views

different DHCP behavior between machines using NetworkManager and not using NetworkManager

can anyone please shed some light on the differences I list below. And maybe explain why NetworkManager does it differently. And please advise if we can change NetworkManager to behave more like the ...
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Libvirt VM Networking fails to start up after upgrading host from Ubuntu 18.04 to 20.04

I upgraded a server from 18.04 to 20.04. I am using libvirt/kvm to host a number of VMs. Some of the VMs failed to reconnect to the network after the upgrade. Two VMs in question run Ubuntu 18.04 and ...
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-1 votes
1 answer
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Different lease duration for dhcp clients

Is it normal in Windows implementation of DHCP Server and DHCP Client that some clietnts gets strange long lease expires time like 15 days? ,,Lease duration for DHCP clients'' setting in DHCP Server ...
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How to include vendor-specific option 17 suboptions 11, 12 and 13 in DHCPv6 solicit/request using dhclient

My request is to include option 17 sub-options 11, 12 and 13 in DHCPv6 solicit/request and I configured the same in dhclient6.conf on my Ubuntu as below. send dhcp6.vendor-opts 00:00:0d:e9:00:0b:00:06:...
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0 votes
1 answer
178 views

2 servers show different behavior when DHCP sever goes down

i dont have any control of the DHCP servers on my network and every 2 weeks or so there is an outage of a few hours where my CentOS 7.8 servers do not get responses to DHCP renewal requests. As far as ...
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1 vote
0 answers
736 views

isc-dhcp dhclient request address endless loop

when a Linux Mint 20 virtualbox VM requests the network config to the home LAN router DHCP through isc-dhcp client with the stock /etc/dhcp/dhclient.conf config file everything runs fine: (BTW 192.168....
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  • 468
1 vote
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107 views

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-...
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0 votes
1 answer
600 views

Internet drops on Ubuntu ISC-DHCP-Client networking

i am having issues with the network connectivity on Ubuntu server 16.04. I am connected to Verizon Fios via Ethernet (it's defined as dhcp on the /etc/network/interfaces file.) The DHCP Client that I ...
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6 votes
0 answers
6k views

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 ...
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Renewing DHCP lease without losing static IPs? (dhclient removes static IPs)

I have this interface, with DHCP and some static IPs: $ ip addr 2: enp3s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000 link/ether e0:d5:5e:...
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Debian Server: DHCP keep IP on reboot

I've a Debian server running with some static IPs and a public IP, all provided by the same ISP on a FTTO connection. Now I've noticed if I unplug the cable between the server and the ISP ONT/ONU and ...
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vbox cloned centos7 fix same ip new to have different ip from cloned one

I cloned centos7 vm in virtualbox, but they ended up with same ip address. My network preferences are my created NAT network with: 10.0.2.0/24 Both vms uses this network i created, but they have same ...
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1 answer
1k views

Networking service timeouts every second restart

The setup My debian server at online.net is running a dual stack ipv4/ipv6 # /etc/network/interfaces auto lo iface lo inet loopback source /etc/network/interfaces.d/* There are 2 files in /etc/...
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1 answer
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eth0 with static ip gets shutdown after dhclient fails

I have a Nvidia Jetson TX2 SoC in an Connecttech Astro carrier board running Ubuntu 16.04. The carrier has two Gigabit Ethernet ports which I would like to configure with static IPs. In system ...
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5 votes
1 answer
8k views

dhclient doesn't set default gateway

I'm running a few Ubuntu 16.04 VMs in the Azure cloud. Whenever I reboot a VM I have to set the default gateway manually. The gateway should be set by dhclient. I activated the debugging and get this:...
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3 votes
1 answer
752 views

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: #...
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1 answer
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Get rid of default "search" entry in "/etc/resolv.conf" on Amazon EC2 Fedora instance

Case of an Amazon EC2 Fedora 23 instance. The file /etc/resolv.conf which determines how DNS lookups are performed by glibc resolver (see man resolv), looks as follows: ; generated by /usr/sbin/...
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4 votes
0 answers
734 views

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/...
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1 vote
0 answers
706 views

ubuntu 14.04 LTS change dhclient lease file location

I cannot find how to change dhclient lease file location. By default (and currently) it is in /var/lib/dhcp, but I want this file to go to another place. I did ps ax | grep dhclient and got this ...
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1 answer
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dhclient: No broadcast interfaces found, but eth0 is up and broadcast

I'm experiencing a common problem with dhclient. But I wasn't able to find a clear solution to this problem. System: ReadyNas RN104 Stock Debian for armhf Just upgraded to Debian Jessie Self-built ...
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3 votes
2 answers
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How to configure dhclient on CentOS to get IP from a specific DHCP server

I have a situation where I am able to launch CentOS 6.6 images on a subnet such that the VM instances get their IP addresses from the virtual gateway of the subnet. Now this gateway has gone wonky and ...
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DHCP attribution without DHCP client

j'ai un serveur DHCP qui attribue des IP selon les adresses MAC des clients. J'ai un client qui n'a pas de client DHCP installé (pas que je sache). I have a DHCP server (on linux) which gives IP ...
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2 answers
2k views

Supersede default route

I have two network interfaces eth1 and wlan0. I would prefer all outbound traffic to go through eth1 before wlan0, but if eth1 is not up, and then wlan0 should handle the traffic. Both interfaces get ...
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8 votes
4 answers
22k views

CentOS 7 is not setting my gateway from DHCP

I have a Minimal Install of CentOS 7. I have disabled the Network Manager as I want to setup my network the "old school" way. systemctl stop NetworkManager systemctl disable NetworkManager ...
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0 votes
1 answer
457 views

Can we force dhclient to not renew ip rules?

I've overridden the ip routing rules on my RHEL machine by adding custom logic in a new script ifup-local that is run immediately after a new interface is attached. /etc/sysconfig/network-scripts/...
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0 votes
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1k views

"ifup eth0" causes dhclient to bring up more than one interface

Can someone tell me why dhclient is not respecting to only handle the one interface it has been passed? I've seen this multiple times over the years; never figured it out - it's not related to ...
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0 votes
1 answer
2k views

Suddenly unable to obain IP address but eth0 port blinking rapidly

After a server restart, the server is unable to obtain an IP address through a wired ethernet interface, neither automatically nor manually. However the green light on the back of the machine where ...
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2 votes
2 answers
13k views

Issue with RHEL7 and disabling NetworkManager

Okay community, let's see if we can figure this one out, cause I'm out of answers. Where I work I am setting up a bunch of RedHat Enterprise Linux servers. There is a collection of RHEL6 and RHEL7 ...
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3 votes
1 answer
5k views

How to remove only IPv6 addresses with iproute2?

I'm trying to write an application that can change the IP address of the local machine. When doing some experimentation, I've noticed that if I freshly connect to a wireless network, I am assigned an ...
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32 votes
2 answers
59k views

dhclient: What does "RTNETLINK answers: File exists" Mean?

I wanted to update the DHCP lease of an Amazon EC2 instance, so I executed the following command: user@host:~$ sudo dhclient Following that, the system's DHCP lease is updated successfully updated. ...
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  • 535
-1 votes
1 answer
3k views

how to Check for dhclient in Directadmin [closed]

I have installed CSF firewall in CentOS 6 64-bit on Directadmin dhclient appears to be running which suggests that the server is obtaining an IP address via DHCP. This can pose a security risk. You ...
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0 votes
1 answer
820 views

CentOS 5 domain-search from DHCP server ignored by dhclient

I have a DHCP server running ISC dhcpd which offers the option domain-search "domain.local"; option. This is being ignored by a particular CentOS 5 dhclient which is removing the search parameter in ...
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2 answers
1k views

How to DHCP request a second, different, IP for the same physical interface?

(Similar to this question, but with two different DHCP-assigned IPs) Is there any way to let dhclient or dhcpcd request two different IPs for one physical interface, e.g. via virtual interfaces eth0 ...
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1 vote
0 answers
940 views

How to send several instances of the vendor-specific options to a DHCP server using dhclient?

I need to send vendor-options to DHCP server using dhclient (ISC). I've added following lines in the dhclient.conf: option dhcp6.vendor-class code 16 = {integer 32, integer 16, string}; send dhcp6....
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1 vote
1 answer
519 views

dhclient asking for new routing every 1500 seconds, removing my static routing, cron not working

I have a problem with cron job on my ubuntu server 12.04. I have two internet providers - one for fast speed, second - for local resources. So, I'm using command route to up the static routing for ...
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1 vote
2 answers
2k views

DHCP clients: Where is the hostname going to come from

We are building a private cloud here, VMs have at least 2 NICs, sometimes 3 or 4, each may be statically configured for IPv4 and/or IPv6 or be configured by DHCP or a combo of the two. Yes it's a ...
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12 votes
2 answers
19k views

Debian 7 how are IPv6 link local addresses set?

It seems like when dhclient runs on eth0 I get an IPv4 address from the DHCP server and a Scope:Link IPv6 address attached to eth0: inet6 addr: fe80::a00:27ff:fed0:4d41/64 Scope:Link But I can't see ...
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  • 223
1 vote
2 answers
2k views

Configuring linux to be visible in microsoft DNS domain

I've been trying to have one of our linux box available in the windows domain. The linux box is a ubuntu server without gui or X installed. All manipulations are done from ssh. Linux box: hostname: ...
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1 vote
1 answer
1k views

How to override the network DHCP Server settings to be specific to my own .conf file?

Basically, I have want to test out WPAD(Web Proxy Autodiscovery Protocol ) , PAC. But I would like to do it without touching the Network DHCP server. So, can you suggest a way in which I can achieve ...
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1 vote
2 answers
763 views

DHCP issue in our network, could it be hidden 2nd DHCP server?

Something weird happened today. We have a TP-LINK wifi router in our office distributing a pool of IPs 192.168.80-200. There are some windows and some linux boxes. One of the linux boxes (CentOS) ...
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0 votes
1 answer
471 views

IPV6: two interfaces with dhclient

I have eth0, eth1. For each interface run dhclient on default port 546 (547 ?). eth1 does not have connection to the network. If dhclient for eth0 bounds before dhclient eth2 starts the eth0 gets IP. ...
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1 answer
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How do I force dhclient to use last known IP?

This is for fault tolerance in a client/server app. The business says that when the network is unavailable, the app must still run. And it will, provided it doesn't lose it's IP address. The problem ...
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7 votes
1 answer
12k views

Mac OSX server command equivalent for dhclient?

Is there an MacOS command that makes a dhcp request, and renews the old lease, drops it for a new one, or usefully reports errors or lack of response from a dhcp server? This would both help fix ...
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1 vote
1 answer
3k views

dhclient and link local address

I am doing a "dhclient" on one of the network interface which is in UP state. There is no DHCP server running in the network on which this node is present. So the questions are Will dhclient try to ...
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2 votes
1 answer
2k views

How to pass a vendor-specific options to a DHCP server using dhclient?

I need to send vendor-options to DHCP server using dhclient (ISC). As I understand I need to describe that options in the dhclient.conf. Do I need make new "space" for options? Or I can do "send"? ...
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1 vote
2 answers
998 views

dhclient requests filling memory?

Dammit Jim, I'm a web developer, not a sys admin. With that out of the way, my client's has a CentOS server (6.2) that is only serving a single Magento site (and the associated MySQL server) and it ...
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7 votes
5 answers
28k views

Why is dhclient issuing a unicast DHCPREQUEST every ~15 seconds instead of at T1/T2 timers?

I am running a CentOS 6.2 server as my gateway and firewall, while also providing some internal services. This is a setup I have had for years using various hardware and distributions (redhat based). ...
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