Questions tagged [dhcp-server]
Dynamic Host Configuration Protocol (DHCP)
534
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What is Option 60 (Vendor Class Identifier) used for in DHCPv4?
Currently I'm using Wireshark to analyze the DHCP process between wireless devices and my DHCP server (which in this case, is my Wi-Fi router).
On all of the devices that I tested, I noticed that each ...
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0
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86
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Reserve IP based on DHCP Option 61 insted of MAC Address
a DHCP client is sending a discovery packet with option 61. Now the Windows server 2019 /2022 needs to respond with the offer based on the DHCP reservation, reservation is registered based on option ...
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1
answer
75
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DHCP server does not provide correct filename for PXE
I'm trying to configure PXE server for both Legacy/UEFI support. So I need to provide different bootloaders based on architecture of machine.
Here's part of dhcpd.conf:
option architecture-type code ...
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1
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19
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Windows DHCP IOT retain same IP
I am trying to address a problem.
We have a windows DHCP server and some devices, which we need to replace on needs. The device has a custom DHCP client which sends DHCP-DISCOVERY Packet with ...
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1
answer
348
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Centos 7 dhcp server not responding to UEFI PXE DISCOVER
I'm trying to set up a Centos 7 server as a dhcp server for PXE (UEFI). I'be tried several changes to the dhcpd.conf file, but nothing seems to make a difference.
dhcpd.conf:
allow booting;
allow ...
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0
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93
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DHCP load balancing added to production and existing clients
I have to ask something I cannot find explained in e.g. https://learn.microsoft.com/en-us/previous-versions/windows/it-pro/windows-server-2012-r2-and-2012/dn338976(v=ws.11) (refers to 2012R2, but that ...
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Migration strategy to migrate a DHCP scope from old DHCP server to new DHCP server as smooth as possible
My current homeLab and entire home is currently running on a single subnet 192.168.0.0/24 with my ISP provided router running a DHCP scope handing out addresses in the 192.168.0.20-192.168.0.254 range,...
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87
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MACs in DHCP reservation are changing randomly
For the second or third time now our dhcp server forgot parts of its reservations and made up random MAC addresses. Why?
We have 2 dhcp servers in failover mode. Everything worked well for years. But ...
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1
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43
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Force sending DHCP options
I have a lab spectrometer that boots using PXE from boot files stored on a computer. They exist inside a local network with the computer acting as both the DHCP and TFTP server.
The spectrometer ...
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1
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183
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Setting up LAN gateway for school club network - "No subnet declaration for enp3s0"
I am a computing teacher, I am trying to setup a "sandbox" network with internet access for an after school computing club.
I have an old PC (Debian 11 installation) with 2 ethernet ...
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103
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Static DHCP reservation via ASDM
We have a Win 2016 server in a datacenter behind a Cisco ASA 5515 running 9.8(4)29. I use ASDM 7.12(2) to manage it. I am very familiar with networking, but rather a novice with Cisco command line ...
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310
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DHCP logs showing (no free leases)
I have setup new isc-dhcp-server in ubuntu 20.04. all client getting connect but showing there logs (no free leases)
client connected only 25 machine.
sudo tail -f /var/log/syslog
Sep 9 09:43:57 ggn-...
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210
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How to send custom DHCP option on all Offer and Ack packets in kea?
I'm using the Kea dhcp server, and I want to use the DHCP options to send data to the server's clients. Following the instructions here, I listed the option with the "always-send": true ...
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389
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Decode UID from dhcpd.leases
I have am testing a device on my network which has this lease assigned:
lease 192.168.110.85 {
starts 3 2022/07/20 16:12:37;
ends 3 2022/07/20 16:22:37;
cltt 3 2022/07/20 16:12:37;
binding ...
- 307
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578
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dhcp: lease expiration vs. infinite lease
As per RFC2131, when the lease expires the client has to stop using the IP address. So do I understand right that if the lease lifetime is set to infinite on the server, then the client does not need ...
- 249
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749
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How to set up OpenVpn client on the Mikrotik for two different PCs with the same credencials for vpn?
I set up OpenVpn client on the router Mikrotik, but for some sites have ERR_NAME_NOT_RESOLVED.
I am using OpenVpn on Ubuntu, but I need to use the same credentials for VPN on two different PCs, when I ...
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libvirt and dnsmasq does not allow to start Kea DHCP server
I have libvirt installed which instantiates dnsmasq process per each virtual bridge interface, e.g. virbr0, however for some reason I can't start kea-dhcp server on other interfaces in the system, ...
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23
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DHCP C class subnet enlarging
We have vlans to separate traffic. Our wireless network is a separate vlan such as scope ID : 192.168.100.0
So we have been using 192.168.100.0 sat on 255.255.255.0 netmask vlan100.
With in the scope ...
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336
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Freeradius with dhcp server: Calls to perl module returns error
This is a continuation of my previous question in sending static routes from Freeradius DHCP server implementation in combination with Strongswan VPN server.
When debugging Freeradius using tcpdump ...
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1
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203
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isc-dhcp-server ip-range speicifc domain-name-server
I'm trying to get an isc-dhcp-server configuration to use different DNS-Servers based on the ip-address assigned.
Basically, I want some of my client marked as not-trusted, which then may not access ...
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354
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Migrating Old Active directory Forest with two domains
We have single AD forest with two domains as follows:
Domain A:
Contains nearly 30 servers (7 physicals and 23 VMs) all hosted on Microsoft Hyper-V server
Nearly 500 Active user accounts
A huge file ...
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728
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Obtaining two DHCP addresses on Linux
There have been various questions asked a long time ago about obtaining two IP addresses via DHCP on Linux. Most of those are still relating to old 'alias interfaces', like eth0:0, which has been ...
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ScreenOS SSG-320M Source Interface Based Routing
quick question. Couldn't figure this out with even the ScreenOS Bible.
Juniper SSG-320M Firewall, Just added an 8port PIM Module(ETH1/0 to 1/7):
ETH0/0(Trust) 172.16.1.1/16
ETH0/2(UnTrust) 192.168.0.5/...
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711
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Implementing rfc3442 (classless static route) in Freeradius DHCP server
I am trying to setup a Strongswan server that runs in split tunnel mode, which means I have to disable using the server as a default gateway on client side and also disable classfull routing in the ...
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1
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195
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DHCP server IP reservation during the "offer" step
How long is the IP reserved by the DHCP server, when it sends the offer message? Imagine the client does not send back the request message, after how much time is the IP available again?
Thanks for ...
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2
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Our cable modem is acting as a rogue DHCP server, even though its DHCP function is supposedly disabled [closed]
We have, for quite some time, had problems with systems on our LAN coming up "bottled," i.e., with non-functional connections. I recently noticed that the assigned IP addresses looked like ...
- 259
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645
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Using DHCP reservations instead of static IP address configuration for servers
I was wondering if it is better to use DHCP reservations for servers and computers that must have static IP address, excluding DHCP servers themselves, Domain Controllers, and DNS servers of course, ...
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114
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static bindings in DHCP server
I'd like to enable static binding in the DHCP server (I'm using KEA Dhcp https://www.isc.org/kea) but I think it is applicable to other implementations as well.
What exactly I want to achieve is to ...
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1k
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dnsmasq DHCP not working, not replying to DHCP requests
I have setup dnsmasq as DHCP server on a CentOS VM, however it is not replying to DHCP requests. What could be the issue? Following is the configuration and tcpdump logs.
interface=ens224
listen-...
- 101
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915
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Can't start isc-dhcp-server due to error " AgentInitCheck: agent comms failure"
I have a Raspberry Pi 4 - Model B, and I'm trying to create an adapter from Wi-Fi to Ethernet using the Pi. I'm currently using this gist as a guide for how to create it, but I keep running into an ...
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299
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ISC DHCP/DDNS setup: Static entries for non-dhcp clients
I have set up a local network with ISC BIND9 and DHCP service. New leases trigger the DHCP to add an A and PTR record which works perfectly.
I also added lots of static host entries in the dhcpd.conf. ...
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1
answer
1k
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Identifying current main DHCP server
There are two DHCP server of the same IP address example.(10.100.9.12 and 10.100.9.13).
The gateway, subnet mask, and DNS is the same.
The current DHCP are running on Vlan9.
Is there any possible way ...
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1
answer
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Windows DHCP not showing the accurate leases
In Windows System Event log, there are DHCP server warnings that IP address range of a scope (10.40.0.0) that available is low.
Windows Event Log
But in the DHCP program, the Address Leases is only ...
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1
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2k
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DHCP NTP Server Option 042 not propagated by Windows Server 2016
I am trying to make NTP server settings available to our non-Microsoft devices on local wired and wireless network. Obviously, they don't know how to use MS AD time info from domain controller.
Our ...
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806
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Problems with WDS on different subnets
I'm setting up a WDS (Windows Deployment Service), the WDS server is in a different subnet than the clients that need PXE.
These subnets are connected through a VPN tunnel.
Routers are pfsense.
But on ...
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304
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isc dhcp multiple option 240 in same subnet
I'm fairly new to isc dhcp.
I'm working at an ISP and need to provide our STB's with an option 240, and it has worked fine for years, the problem now is that we are getting a newer model, that needs a ...
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2
answers
884
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Query IP/hostnames in local network (Windows)
I have a Windows Server based network, running a Windows DHCP and DNS server. How can I list all the computers in the local network known to the server? That would mean querying either the DHCP or the ...
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Going to implement new Infrastructure in HQ Office with 1 firewall, 1 L3 Switch, 5 L2 Switch, 2 Managed WIFI AP and 1 Server [closed]
Im going Implement Network in HQ Office which will link also with Branches Office. What IP Address Class is recommended on this scenario? Need some assist to Kick Off on this. I have 1 unit Fortigate ...
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2
answers
816
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How does a client find the DHCP server on network if DHCP is disabled on the router? [closed]
I am an acting, self-taught network administrator, so please excuse me if this should be obvious. I have a Windows network with domain controllers running DHCP. My gateway/router is a Meraki MX67 that ...
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1
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144
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What is default IPv6 configuration on routers
I've just started learning IPv6. I have a router running OpenWrt and I would like to configure it to use IPv6. As I know this address can be assigning to a client with or without DHCPv6 server. Do you ...
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472
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DHCP Pools on Ubuntu DHCP server not working properly
Mac addresses ending with "55:a3" and "56:2a" are also ending up in last pool
123 match if binary-to-ascii(16,8,":",substring(hardware, 5, 6)) = "55:a3"; ...
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dhcpd server invalid mac detection
On my dhcp configuration, i have on commit hook to save device information. My problem is some of the mac addresses becomes invalid:
8:7c:39:cf:b6:3f - this should start with zero
8:d0:b7:52:f9:68 - ...
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3k
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The specified package is not valid Windows package. Error: 0x800f0805
I installed Windows Server 2016 on VirtualBox, and now I am trying to install DHCP server on my Windows Server 2016 machine, but I got an error. I set this machine as a Domain Controller before, so I ...
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3k
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Is it possible to force the DHCP server to assign a different IP address each time the address is renewed?
I need to detect IP address renewals in my C++ Linux application and check if the new address is different from the old one. I have access to a router running OpenWrt. I can change the lease time, but ...
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1
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201
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DHCP Server received Discover mesage but not responding with Offer mesage
I using DHCP (windows server 2019 standard) for multiple scopes witch DHCP relay is Cisco 3750 L3 switch.
For the first time, it's working normally but after about 8 hours the DHCP server received ...
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1
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475
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Can I have two DHCP servers for IPv4/IPv6?
I have an IPv6 block, However the network is based on an IPv4 only router. I can't change that router for several reasons.
Can I have a DHCPv6 server with DHCPv4 server? Or do I have to disable DHCPv4 ...
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4k
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Mikrotik: HowTo pre-define static leases in DCHP-server
I would like to replace my current router by a Mikrotik (v6.48.3). In order not to mess up my network, I would like to pre-set the IP addresses the DHCP clients will get from the server. I do not find ...
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1
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1k
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Refreshing Windows DHCP Server reservation active/inactive state
I have a Windows DHCP server with a number of reservations. These all seem to work correctly (in that the addresses are correctly distributed) but, somehow, the Active/Inactive state of these has ...
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1k
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What is the exact meaning of "On Commit" in ISC DHCP server configuration?
I know there are three kinds of events we can use for scripting in ISC dhcpd -- commit, expire and lease. My problem is, I am having a little problem in understanding the "commit" event. I ...
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102
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What DHCP option tags are used by standards but not recorded?
I've been working on setting up an in-house service that uses DHCP to let clients auto-discover the server's location. I took a look at IANA's BOOTP and DHCP option tags to see what's available to use,...
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