Questions tagged [dhcpd]

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Dhcpd won't start due to selinux

have searched tirelessly and can't find an answer to this thats not confusing. I have a clean install of centos 6.2 32bit on a machine I use as a router. with selinux enabled dhcpd refuses to start ...
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29 views

Force dhclient to always provide a unique IP from the available pool

I'm running RHEL 7.4 and the dhcpd is controlled by DD-WRT off my router. Tried to use: dhclient -r; dhclient -x; rm -f /var/lib/dhclient.leases; ip a; dhclient -v but it either returns the same ...
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186 views

CentOS 7 DHCP server, get IP but cannot ping server or client

I'm trying to create a nat, however, before I can get that far I need to network two PCs via ethernet. The server looks like this: 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state ...
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1answer
66 views

Exclude subnets from distribution?

In Windows' DHCP server it is possible to exclude an entire subnet from being given out to clients which doesn't have a reservation. They call this "IP addresses excluded from distribution". Now I ...
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1answer
484 views

Edgerouter DNSmasq send updates to BIND

TL;DR: How do I configure the Ubiquiti EdgeRouter, running DNSmasq or DHCPd, and NSupdate, to send its DHCP leases to a central BIND server? I have a system comprised of a few Ubiquiti EdgeRouter X's ...
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Weird answer of linux DHCP server to gratitious ARP causes DHCP failure

This is a problem, that I ran into recently on a quite heavily configured linux server. This machine runs Samba as an Active Directory Domain Controller, a mail server, a web server, two virtual ...
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1answer
455 views

Multiple IPv6 routers on the same network

I have two ISPs for my home network. They are connected to two separate routers. If I run radvd and dhcpd on both routers at the same time, I get no IPv6 connectivity. My IPv6 connectivity only works ...
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1answer
560 views

DHCP and logging fixed address “leases”

I have been tooling with a dhcpd server that i have been setting up for, well, for the general excitement of it i guess. I have a bunch of different configurations. I have noticed that fixed-address ...
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1answer
404 views

How can I configure DHCP server to issue the same fixed-address by matching with the client identifier in the discover message

I am able to config fixed ip address with hardware ethernet options, but i am trying to assign fixed ip based on client id(option 61) from DISCOVER message. I tried with below configs , but it doesn't ...
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59 views

dhcpd hostgroup in a single file

Is it possible to set dhcpd to read MAC addresses from file, and then to set IP and hostname for those particular hosts? To be more clear - everything is supposed to be in that file: mac, ip and ...
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1answer
1k views

Option 81 in DHCP

Just curious about this. When we enable option 81 on a DHCP network, the DHCP server will start updating the zone that comes along with the client's FQDN. Now, how would client will ever know its ...
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1answer
2k views

how to block incoming DHCP DISCOVERY messages

I'm running ISC DHCP deamon on centOS and want to block unwanted(by clients MAC address) discovery messages before they reach dhcpd. how can I do this with iptables or anything else?
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1answer
55 views

dhcpd daemon taking huge amount of memory and restarting with out of memory error

I have to configure isc-dhcp-server for 1 million clients which listens on 4094 vlan tagged interfaces, where each vlan interface is mapped to a subnet declaration. Therefore in total 4094 subnet ...
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1answer
2k views

Unable to add forward map …: SERVFAIL

DHCPD[4.3.5] error: Unable to add forward map from nvhenz710.hen.mentats.us to 172.24.1.31: SERVFAIL no errs in BIND 9.11.1-P2-RedHat-9.11.1-2.P2.fc26 $ groups named dhcpd named : named dhcpd ...
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2answers
49 views

How To Use host tag In dhcp.conf

My question is simple. I tried to assign a fixed IP address to wlan0 connected users using dhcp.conf. From configuration file: host clientA{ hardware ethernet 00:80:c6:f6:72:00; fixed-address 192....
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1answer
911 views

Isc-Dhcpserver static DHCP missing client-hostname

I got a strange problem with my isc-dhcpserver (Ubuntu 16.04). When clients are requesting from the server, I can see the following output in /var/log/syslog : Jun 21 21:41:25 drake dhcpd[265]: ...
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1answer
1k views

DHCP Client starts sending DHCP Discover messages upon receiving a NAK from another DHCP server

I am trying to set up a DHCP client that is supposed to get its IP address via DHCP. I have configured two DHCP servers (one in 192.168.X.X pool and the other in 162.16.X.X pool). Then, the client ...
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50 views

DHCPS - single mac whitelist, multiple subnets

I am trying to reduce the size of my broadcast domain and, in order to do this, I need to permit hosts from being able to move from one subnet to another at will. We use a mac whitelist for our dhcp ...
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1answer
125 views

dhcpd.conf DNS order is being reset after each cobbler sync

I'm trying to switch the order of DNS servers that my clients machines use by editing the /etc/dhcp/dhcpd.conf file in cobbler. This was the settings before I attempted the change: subnet 10.100.48.0 ...
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2answers
19k views

CentOS 7 DHCP server fails to start (won't enable on specified port)

I have a Cent0S 7 miniPC with a wireless and wired network ports. The wireless port (wlp3s0) is connected as a DHCP client with 192.168.10.X addressing and has DNS resolution. I'm trying to setup the ...
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114 views

dhcp server not starting on CentOS 5 (XenServer 6.5)

I have a host with XenServer 6.5 (based on CentOS 5) that is currently set up using a static IP by following the procedure here. I have been provided with an IP address, netmask and gateway - I ...
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1answer
195 views

DHCP leases file has 200+ instances of the same lease?

I'm not sure what's going on here. I have a CentOS 7 DHCP server, and the leases file is growing at a linear but steady rate - it's re-issuing the same lease to the same MAC over and over again, and ...
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1answer
910 views

“match hardware” in dhcpd.conf not working

I've been trying to get mac addresses with a certain OUI into a certain address pool. I haven't been able to get it to work at all. Here is a snippet of my dhcpd.conf and how it's applied. class "...
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1answer
1k views

How can I clear the DHCP GUI in OSX Server? Ghost clients in the building

I have a few client machines showing up in the network (not only in Server.app but also in various logs), which have "Computer Names" (Bonjour names in Apple-speak) which I don't recognize, but ...
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2answers
4k views

dhcpd not offering reserved static IP returns unknown lease

typically when I reserve an IP for a MAC addr the device when booting up and requesting a dhcp address, will pick up the address I reserved. However recently the request looks like it comes in but ...
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1answer
169 views

fedora dhcpd name server configuration

I'm having a hard time configuring a more modern release of a Fedora DHCP service to replace an older one and the problem is that clients aren't getting the appropriate DNS server information. I had ...
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2answers
6k views

WiFi access point without internet access - iOS devices disconnect

I'm trying to configure a WiFi access point to offer a web service on the local network, without offering clients internet access. The web server has a fixed IP address (let's say 192.168.2.2) and for ...
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1answer
1k views

Client getting wrong option from DHCP server

I'm setting up a machine to load a Debian intallation with PXEBoot, following the guide on the Debian Wiki. I have the boot image sitting on a server, pxe.example.com, at /var/lib/tftpboot/debian-...
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1answer
1k views

dhcpd.conf for PXE/BOOTP boot not working

I'm trying to configure the dhcpd.conf file so that when I boot through the network using PXE / BOOTP, a bare metal server or a virtual machine (KVM) would get an IP address in the 10.0.2.100 to 10.0....
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1answer
721 views

Cobbler/TFTP: No filename or root path specified, but why?

I've installed a new Cobbler server and configured it as a DHCP /TFTP server. I've configured the /etc/dhcp/dhcpd.conf like so: [root@centolel ~]# cat /etc/dhcp/dhcpd.conf ddns-update-style interim; ...
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2answers
1k views

Release dhcp lease after forcing client to disconnect

I configured a wifi access point based on OpenWRT to limit the number of clients to 4 at the same time. For that purpose I gave a limited number (4) IP addresses leaseable by DHCP. After a period of ...
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1answer
145 views

Obtaining the running config for dhcpd

Is it possible to obtain the current running config for dhcpd? I inadvertently wiped dhcpd.conf but have not yet restarted the service. It is currently assigning the correct IPs to my test ...
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2answers
3k views

How to block DHCP traffic using iptables

First let me describe my environment: There is a VM (CentOS) acting as a gateway The gateway VM has to NICs, eth0 connects to public network, eth1 connects to private network eth0 get IP from public ...
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1answer
2k views

DHCP with fixed IP hosts (Ubuntu)

I'm managing an office system that assigns IPs based on the MAC address. The fixed hosts are added in a dhcpd-hosts.conf file which is included in dhcpd.conf. There are some PCs that are not in the ...
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378 views

How can I assign an IP by UID in DHCPd

Here was answered how to assign an IP by MAC address. I want DHCPd server to assign IP by UID. Can i just add record to dhcpd.conf in the same manner? For example: host example { uid 00:...
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1k views

Restrict hostapd wireless client from talking to eachother

How can I keep a wireless client of hostapd from talking to a wired client on the same network or another wireless client on the same network? Here's my network topology: [wired client] --> [...
3
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1answer
531 views

2 client classes sharing the same subnet range

basically I would like to achieve the followings: using only one subnet different types of user sharing this subnets creating 2 pools accordingly an user class called "l2vpn_user" if matched by MAC ...
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0answers
85 views

DHCPD does not allow filename option with a colon in it

For some reason, tftpboot does not work with a colon in filename parameter: group { filename "node7:linux/pxelinux.0"; host machine_7a { hardware ethernet 02:01:02:02:01:11; fixed-...
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2answers
1k views

OpenBSD ISC-DHCP IPv6 not working?

How to enable dhcp for ipv6 in OpenBSD 5.5. Default dhcpd don't know about IPv6, it says that option -6 is incorrect and do not understand ipv6 config. But it has version 4.X that IPv6 must be enabled ...
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2answers
1k views

ISC dhcpd dynamic bootfile-name. Is this possible?

Actually I want to dinamically assign bootfile-name based on clients MAC. I have tried this config: option bootfile-name concat( binary-to-ascii(16, 8, "", substring (hardware, 1, 6)), ".cfg"); But ...
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1answer
2k views

Cleanup DHCPD leases as well as DDNS Entries

I have a fairly simple set up on a Debian server I'm running. I currently have isc-dhcp-server installed along with bind9. I set up my zone and my reverse lookup zones and set up dynamic updates, it's ...
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0answers
217 views

Assigning option based on class membership inside the subnet section

We are looking for a way to do something along these lines in the dhcpd.conf file: subnet ... { #couple of options for the subnet here pool { allow members of "class-name1"; ...
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4answers
3k views

Fixed dhcp host to automatically expire any lease

I have the following situation: Multiple offices with multiple firewall/dhcp servers. Every time the IT team of some office plugs a new network printer i need to create a fixed-address entry, and ...
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1answer
2k views

ISC DHCP Server scope error

Why am I getting the following error after modifying my dhcpd server config? option space definitions may not be scoped
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4answers
50k views

How can I assign an IP by MAC address in dhcpd

How do I assign an IP address specific to a mac address using dhcpd? So far I have tried host blah { hardware ethernet <mac address>; fixed-address <ip address>;} in my dhcpd.conf. But ...
3
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1answer
970 views

How can I configure dhcpd to only update the reverse zone in bind?

I've got dhcpd pushing updates to bind, and it seems to be working fine: named[24161]: client 192.168.10.1#59141: signer "dhcp_updater" approved named[24161]: client 192.168.10.1#59141: updating zone ...
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2answers
7k views

Linux dhcpd server with multiple scopes to assign IP based on request source

I have configured a Linux dhcpd server with multiple scopes on the same interface(eth0). The devices which needs these IP address(DHCP clients) are on two different remote networks. The networking ...
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3answers
4k views

DHCPD clean leases on client disconnect

Is there a way to force ISC DHCPD to trigger expire or release for static lease right after client disconnect? I want to trigger a script right after client connects ("on commit" DHCPD event) and ...
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1answer
1k views

Enterprise DHCP server solution? [closed]

I have a network of about 1000 assorted devices, all of witch are running by static IP addressing. Given the size of the network and the lapse of technical advice, the addressing scheme is in chaos ...
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2answers
20k views

DDNS, BIND and leftover .jnl files

I have configured BIND and ISC DHCPD to work together (using keys for updates). Now it's not that it does not work at all: forward maps etc are most often added. However, very often, for no apparent ...