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Questions tagged [dhcp-server]

Dynamic Host Configuration Protocol (DHCP)

2
votes
2answers
39 views

Unable to add two scopes?

I am trying to add two scopes of different range say (192.168.0.5-192.168.0.10), (192.168.0.15-192.168.0.25) on windows DHCP server while I am trying to add the second scope it says the address range ...
0
votes
0answers
26 views

DHCP Server (Centos 7) Dynamic and static leases present for… ignore?

I have been running my own DHCP server on Cento6, now 7 for a number of years. I've never had any real issue. Something strange happened, a device wasn't joining the network after rebooting it, so I ...
0
votes
0answers
47 views

dhcp server not responding to clients who are making connections the second time and onwards

I have setup a DHCP server on my Ubuntu 14 laptop. eth0 is the port I am using for DHCP server and listed with same name in ifconfig. I followed the exact following steps : Step 1 : sudo apt-get ...
0
votes
1answer
110 views

Ubuntu 18.04 DHCP server can't pass its DHCPOFFER to clients (endless DHCPDISCOVER/DHCPOFFER loop)

I noticed that on Ubuntu 18.04.1 DHCP server (isc-dhcp-server) always responds (DHCPOFFER) directly to the IP it offers to the host having sent DHCPDISCOVER. The DHCPDISCOVER packet has its Broadcast ...
0
votes
2answers
78 views

Why does my Windows DHCP server hand out a non-configured subnet mask?

We run the DHCP server role on our domain controller (Windows SBS 2011). We want our LAN subnet to be restricted 10.1.1.0/24 (unsure if this is the correct notation but our subnet to be restricted ...
0
votes
1answer
56 views

DHCP not sharing Internet access

I have several Virtual Machines in Vmware ESXi 6.5 with 2 Network Groups. Created a DHCP Server Machine on CentOs with 2 networks interface. 1 / vm network from which it takes a network and has IP ...
0
votes
0answers
34 views

Is the latest dhcp spec (rfc4361) invisable to admins?

When having an old Winsdows 2003 dhcp server, which doesn't understand the dhcp identifier OS'es such as Fedora 29 and Ubuntu 18.04 server sends. Which looks like 10,11/09/18,12:28:17,Assign,192.168....
0
votes
1answer
49 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 ...
-1
votes
1answer
77 views

DHCP in Azure in case of fail in Onprem [closed]

Please confirm can we install DHCP server in Azure. Actually, we want to use this Azure DHCP in case of DHCP fail in Onprem. Please confirm how can we enable the same IP addresses in the Azure by ...
1
vote
0answers
183 views

Dynamic DNS client records not being updated correctly

Our network is running Windows and macOS clients all of which are joined to Active Directory. The Macs are all running Windows via Bootcamp. We were having issues which were being caused by our macOS ...
0
votes
0answers
38 views

Windows Server DHCP option 152

According to this document option 152 for DHCP servers shout provide base-time for clients. According to this RFC draft it should contain absolute time ( unix epoch): The base-time option is the ...
1
vote
0answers
35 views

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 ...
0
votes
0answers
27 views

SonicWALL TZ205 IP Helper policy

Network connection: SonicWALL TZ205 port X1 is connected to ISP. Port X0 is connected to a Netgear switch. Windows Server 2012 R2 (AD DC, DNS & DHCP services) is connected to the Netgear ...
0
votes
0answers
48 views

Remove damaged RRAS server from domain network

I have 2 Windows Server 2012 R2 servers in the domain network. Server A was running RRAS and VPN services. Server B is running AD DC, DNS and DHCP services. Server A was broken and cannot be ...
0
votes
0answers
129 views

Why would ISC dhcpd ignore vendor options?

I'm trying to use an existing dhcpd to autoconfigure Raritan networked PDUs. This works roughly like PXE booting: there are additional DHCP options that direct the device to fetch a config file via ...
0
votes
0answers
125 views

How do you keep Windows from changing DHCP Reservation Names

It is a SBS-2011 Server. I will create a new DHCP reservation and set the reservation name to "GSMPC-11 N". Then it looks like when it goes active Windows changes the name to the computername.domain i....
0
votes
2answers
237 views

Two DHCP servers giving static addresses in a network

I have a network having two servers that are occasionally booted. I wish to maintain DHCP services even during a boot of one server. One of the servers currently has a DHCP server that gives static ...
0
votes
0answers
144 views

How to sync a Linux secondary DHCP server?

In this article they don't explain how the secondary DHCP server gets synced and in this one they sync the files with home made scripts. Question Having a secondary DHCP server is good practice I'd ...
0
votes
2answers
107 views

Disabled dhcp-server on router prevents clients from getting an address

I have a weird issue on my local network which prevents some clients, sometimes acquiring an ip address from the real dhcp-server (x.x.x.3). The dhcp-server is a CentOS VM running isc-dhcp-server for ...
0
votes
1answer
431 views

Setting up pfSense to bridge LAN NICs and connect WAN

I have a machine with four NICs (physical ethernet ports) and I'd like to set up a fully updated pfSense on it. So far it looks like this: A few things I've done so far: I've set up the bridge ("...
4
votes
1answer
135 views

Why is this checkbox disabled in Windows DHCP server range policy / vendor class management?

I manage several Windows 2012 based DHCP servers and on one of these I came across a peculiarity that I cannot explain and do not know where to correct: In DHCP manager*, expand [server name], then ...
0
votes
1answer
143 views

Have freeRadius/Linuxcooperate with DHCP-Server/Windows

We have freeRadius for authentication on a Ubuntu box, but the DHCP allocation is handled elsewhere, specifically by a Win2012R2 DHCP server. Is it possible to configure freeRadius in such a way that ...
1
vote
1answer
2k views

How to reserve a static-ip on Mikrotik router for a device that is attached to a fixed router's Ethernet port

I am trying hard to figure out how can I force any DHCP client device connects to the port ETH10 on Mikrotik router get assigned a fixed IP-address. Please note that the device MAC address is unknown ...
0
votes
0answers
18 views

Why is 2008r2 server making leases for itself in the DHCP scope?

I thought that the block of DHCP leases reserved by the server itself were for the Remote Access services, to hold them for the remote clients that might connect. I have moved VPN services to a ...
0
votes
1answer
33 views

How to configure second wireless router via VLAN trunk? [closed]

I am trying to figure how to configure the second wireless router, but I got stuck while trying to get the following configuration: For all VLANs (0-3), the primary router is the DHCP server for IPv4 ...
0
votes
0answers
14 views

When to switch to Link Local Address

If a networking embedded device that has no routable configuration but DHCP enabled and receives no response from any DHCP server in the network - should the device switch over to Link Local ...
0
votes
1answer
381 views

install DHCP on Windows Server 2016, but not start the Service

I am migrating from an Windows SBS 2008 to a new Server 2016 Machine. Now I want to install the DHCP Server on my targetserver and I know how to do that. In order to avoid 2 servers interfering with ...
0
votes
1answer
94 views

DHCP router option disregarded by all clients

My WAN router, a TP-LINK Archer C2 doesn't have a local DNS server for DHCP'd clients so I was looking for another solution. I found the Dual DHCP DNS Server for Windows and installed it on the LAN ...
1
vote
0answers
222 views

DHCP not working on RTL8111 NIC (DHCP Offer not arriving at receiver)

I'm experiencing some strange behaviour with a Dual Gigabit Ethernet NIC; I've setup a computer which has multiple network interfaces to connect some industrial cameras and setup a DHCP Server (isc-...
3
votes
3answers
623 views

What happens to DHCP sessions on client devices when the DHCP server breaks down and comes online after an interval?

Scenario: I use DHCP server to authenticate and provide specific services to my device. Everything is working well, my client device has a valid IP address 192.168.0.2 and a QoS service assigned by ...
0
votes
0answers
312 views

Configure DHCP Server in KVM Guest to provision all other KVM Guests

I set up a DHCP server in a KVM Guest inside a CentOS7 box. What I want is this DHCP Server to provide addresses to all other installed VMs and, if possible, the main host as well. The network used ...
0
votes
2answers
864 views

How do I find my DHCP server in Windows when I have a non-DHCP assigned IP address?

I work in an environment where we sometimes only have access to the servers and we always set up servers with static IPs. When I run our reports I need to check DHCP IP ranges and sometimes our ...
0
votes
1answer
31 views

What are the priorities when assigning IPs?

When deploying dnsmasq in order to server both DNS and DHCP I have a hard time understanding the priority of various settings. The network, DHCP-wise, is composed of various devices: the ones which ...
0
votes
1answer
471 views

DHCP relay not relaying responses

DHCP Relay NICs: NIC 1: connection to DHCP server (assigned by 172.20.0.1): enp1s0 Link encap:Ethernet HWaddr 00:e0:4c:68:39:0d inet addr:172.20.0.103 Bcast:172.20.0.255 Mask:255....
0
votes
1answer
599 views

Are static IP's supposed to show up in DHCP.leases list?

I messed with the dhcp.leases file (removed, and remade it) hoping it would force the IP's to repopulate. That was a mistake.. I think I have fixed it by reinstalling though. Anyway, I setup static ...
0
votes
1answer
120 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 ...
2
votes
1answer
110 views

Have a script receive an IP from the DHCP server?

None of the Nagios DHCP check plugins can actually take an IP from the DHCP server as a real test. All they do is ask which IP it would give to a certain mac address. Our DHCP server failed, where ...
0
votes
0answers
2k views

How to configure DHCP for wireless clients on TP-Link N Modem Router?

I have a TP-Link TD-8961ND Wireless N ADSL2+ modem router with which I would like to deploy wireless internet in a meeting room. The Internet source is an Ethernet cable which I connect to one of the ...
1
vote
1answer
396 views

Linux DHCPv6 server for PD on ppp interfaces

I need to configure prefix delegation on PPPoE. What is the best DHCPv6 server implementation for this? So far I checked the following: isc-dhcp-server - doesn't work with PPP interfaces dibbler - ...
0
votes
0answers
18 views

Clients continuously get new ips from server 2012 DHCP

Clients continuously get new ips from server 2012 DHCP. I can release and renew and get a new ip every time. I am also not able to configure reservations for the same machines. I have considered the ...
-1
votes
1answer
80 views

VCenter has failed, DHCP server is down

Our VCenter is crashing and technicians are trying to work on it, however this has resulted in the DHCP server failing, therefore none of the machines on the network can connect to the Domain ...
0
votes
1answer
65 views

Windows dns messed up

Our small windows domain is based on two old 2003 server which are domain controllers. They both have dns server and dhcp server running on them. Each dhcp server has its own range of ip addresses in ...
0
votes
1answer
56 views

Does a DHCP client is expected to send DHCP request unicast to the Server in the event of a Unplug/replug or eth0 down and up?

I would like to understand if the DHCP client running in our embedded device is expected to send DHCP request unicasted to the server in the following events? Eth0 goes down and comes back online ...
0
votes
0answers
71 views

Default gateway settings on DHCP NIC

I'm kinda new in the Server world. I have a Windows Server with two NICs, one for internet and one for DHCP on the LAN - however, the second NIC shows up as "unidentified network" and I cant change ...
2
votes
0answers
84 views

DNS issue when communicating with Windows Server 2012 R2

I have upgraded my Windows Server 2008 R2 to a new Windows Server 2012 R2 and installed AD DS, but when to trying to join other PCs to the domain it gives the following error: The specified domain ...
0
votes
0answers
457 views

Migrate windows server 2008 r2 and 2012 to 2016

I'm preparing to migrate our old infrastructure to windows server 2016, currently I have multiple windows servers: ONE Windows server 2008 r2 with role of DC, Exchange, File Server, DHCP Server and ...
0
votes
1answer
695 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 ...
1
vote
2answers
1k views

DHCP relay through different subnets

A TP-Link W8980 acts as a DHCP server on 192.168.0.0/24 subnet. This is also the only wifi access point. A Zyxel USG 50 is connected to it through its 2 WAN ports and has static addresses 192.168.0....
0
votes
2answers
600 views

DHCP server problems with static IP clients

lately I've been having some problems with my DHCP and my clients IP. So basically, in my netwrok I have a DHCP server (Windows 2012 R2) which is working fine (when you connect to the network you get ...
2
votes
0answers
54 views

ISC DHCP (Infoblox) takes 30+ seconds to respond to DISCOVERS

Client's DISCOVER packets reach the Infoblox DHCP server through DHCP relays, but Infoblox doesn't seem to be responding. I checked the pcap taken from the DHCP server, I can see there is 3 DISCOVERS ...