Stack Exchange Network

Stack Exchange network consists of 174 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

Questions tagged [dhcp]

DHCP stands for Dynamic Host Configuration Protocol and is an auto configuration protocol used on IP networks and an extension of the Bootstrap Protocol.

0
votes
0answers
19 views

When connecting 2 routers to my network I end up with 2 IPV6 addresses. How can I control / stop this? [on hold]

I'm trying to use a spare router as a wireless access point on my network - I've given it a static address and disabled DHCP, however when I plug this into the network I end up with two ipv6 addresses!...
0
votes
0answers
13 views

Home server DNS resolution with dnsmasq [on hold]

Pulling my hair for days here setting up DNS and DHCP with dnsmasq and the new way of doing things with netplan. WAN-router is on 192.168.0.1 - works fine LAN-router (Ubuntu 18.04) received 192.168....
1
vote
1answer
22 views

can pfSense captive portal grant internet access to IP which is assigned by Windows DHCP server only?

In our organization we have a wifi access point and IP addresses are assigned by a Windows DHCP server. We have MAC filtering enabled for internet access in the DHCP server but the issue is that if ...
0
votes
0answers
19 views

Windows server dhcp issues when changing vlan

I have an issue with my dhcp server under windows 2012R2. I have many subnets requesting IP to my dhcp server: 10.20.20.0/24 10.20.21.0/24 10.20.22.0/24 10.20.23.0/24 10.20.24.0/24 Each one of them ...
0
votes
1answer
38 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
19 views

Why restriction on minimum lease time in DHCP protocol removed in RFC 2131

While going through RFC 2131 for DHCP I came across a section which titles 1.1 Changes to RFC 1541 under which it mentions that The minimum lease time restriction has been removed I went through RFC ...
0
votes
0answers
22 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
31 views

windows machine gets assigned wrong netmask

I have a Debian based DHCP server. It assigns correct netmask 225.225.225.0 for all devices (WiFi router, voip, scanner) except for the windows machines. They all get assigned 224.0.0.0 for some ...
1
vote
1answer
24 views

Resolution error of specific IP addersses

I have a network with the following topology: +-----------+ +-----------+ |192.168.1.1+---+--->192.168.1.7| +-----------+ | +-----------+ server | windows | ...
1
vote
1answer
19 views

Migrating DHCP from one server and subnet to another, one subnet fails to retrieve addresses

I just attempted to migrate the DHCP service from a 2008r2 server on vlan1 to a 2012r2 server on vlan20. We had the dhcp helpers assigned on the core switch, firewall dhcp relays setup for the any ...
0
votes
1answer
24 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 ...
2
votes
1answer
65 views

OpenVPN: Addressing remote LANs

I've been trying to solve this problem for a while now, but to no avail. We basically have an OpenVPN server to which our end devices need to connect. Some of those devices can directly connect to the ...
1
vote
0answers
34 views

IPV6 Small Business Implementation - Windows DHCP/DNS, PFSense, IPV6

I have some confusion about IPV6 on a Small Business Network. I'm sure one part or the other is covered extensively, but I can't seem to find answers. (Background info) I have a home network that ...
0
votes
2answers
43 views

Libvirt networking: Set default gateway for guest VMs via DHCP

Is it possible to set a default gateway for the guest VMs via DHCP in libvirt? I have the following config <ip address='192.168.123.1' netmask='255.255.255.0'> <dhcp> <range ...
0
votes
1answer
31 views

IP phones get DHCP NAK from superscope configured DHCP server

We are experiencing a strange problem with our 2012R2 DHCP server. Setup looks like this: Superscope with two scopes: SCOPE 1 - 192.168.100.0/24 (for PC) SCOPE 2 - 192.168.101.0/24 (for IP phones) No ...
1
vote
2answers
74 views

KVM: Hosts with private and public IPs

We have a small block of static IPs (e.g. 203.0.113.0/29). We currently only use 203.0.113.2 for a mail server. We'd like to add some other public servers, and if possible would like to have them ...
2
votes
1answer
63 views

How to share VPN and DHCP server across multiple hosts?

I need to set up a small computer network for what is effectively a satellite office for a business. The small network consists of several workstations and a server. The server machine has two ...
3
votes
2answers
402 views

How to add another address range to DHCP server

Short version Long Version Window Server 2012 DHCP server is currently configured as: Subnet: 10.0.x.x (e.g. 10.0.0.0/16) Dynamic IP Range: 10.0.0.12 - 10.0.0.120 This is done to limit dynamically ...
1
vote
0answers
72 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
25 views

DHCP request on ethernet cable reconnect with Ubuntu 16.04 Server

I have Ubuntu 16.04 Server here. My Ethernet interface is configured to use DHCP via /etc/network/interfaces and also I enabled "allow-hotplug" for the interface. It works. I can boot without cable ...
0
votes
1answer
36 views

Specific dhcp administration across multiple dhcp servers

Currently we have multiple DCs in our primary site and a remote location which has its own DC. All of those DCs are on the same domain, though. The remote IT team wants to be able to manage their ...
2
votes
2answers
337 views

How to add a static secondary IP to a DHCP interface using netplan?

My server has a file /etc/netplan/50-cloud-init.yaml with the following content: # This file is generated from information provided by # the datasource. Changes to it will not persist across an ...
0
votes
0answers
35 views

Clients cannot get IPs after lease expires

Got a strange issue involving our wireless network. We have Ubiquiti AP's and have two different networks. One, our internal network gets IP's from our on-site DHCP server. The other network for ...
1
vote
0answers
31 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
1answer
75 views

Mint & Ubuntu don't work on LAN, work on other networks

Good evening, We have 15-20 devices running on our office LAN. Suddenly last week, the internet (both wired and wireless) suddenly cut-off on both of 2 Mint desktops. By cut-off i mean that the wifi ...
0
votes
1answer
60 views

With static IP on Hyper-V ping to VM fails

I have configured a VM on Hyper-v. With the VM network adapter configured to receive DHCP the ping works fine but when I set it to static IP address ping from host to VM always returns time out .I am ...
0
votes
2answers
30 views

Moving from a dual ISP set up to a single ISP facility with mixed IP handling (DHCP with Static IPs)

First time posting a question here, please bear with me. I've been assigned to manage the migration of all our computers and servers from a facility where we have 2 ISP's to a facility where we're ...
0
votes
0answers
12 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
1answer
47 views

How to get an DHCP allocated IP address without a reboot?

I have a server which currently staticly addressed with an entry in its /etc/hosts file, e.g.: 127.0.0.1 localhost localhost.localdomain localhost4 localhost4.localdomain4 ::1 localhost ...
1
vote
1answer
17 views

Server 2016, Using Different Bootfiles to Deploy Company Specific Images

I have a switch with 3 VLANs. I have a WDS server (with DHCP and DNS) with 3 virtual NICs, each NIC is tied to one of those VLANs. Each VLAN corresponds to a company that we work with. I have 3 scopes ...
0
votes
1answer
55 views

How to get the number of devices connected to openwrt in realtime?

I tryed cat /tmp/dhcp.leases | wc -l but have a time delay. Is there any way to get the number of devices in real time, including wired and wireless devices?
0
votes
0answers
30 views

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 ...
-1
votes
1answer
29 views

Multi router network and IPv6 DHCP/RA issues - How to assign default routers?

I've again got problems with our LAN. There are 4 WAN gateways all on the same subnet, all with 100M uplink. On IPv4 I advertise default routers using a ISC DHCP Server. On IPv6 there doesn't seem to ...
0
votes
0answers
36 views

CentOS 7 Server gets IPv6 suffix, but not prefix

I have a server that I'm pulling my hair out with. After total a reinstall, ipv6 works fine until I reboot the system. After that, it only ever picks up the suffix address: 2: enp1s0: <BROADCAST,...
1
vote
1answer
116 views

Failing to PXE Boot UEFI Server

I've been having a lot of issues with UEFI boots lately. I have two VMs that I've been using for testing. One is running DHCP/TFTP (CentOS 7) and the other is a client set to UEFI boot. I have ...
0
votes
0answers
24 views

Mininet+ GNS3: pingall fails + dhcp doesn't work

I'm still a beginner, I'm facing some issues and I need your help. 1 I integrated mininet to gns3 successfully, the mininet VM can ping all the routers and other VMs, Also it can get an address ...
0
votes
1answer
21 views

Replacing Windows Server 11 with NAS

I have been running a Windows SBS 11 via VM Ware, it is on its last legs and I have copied the last database to a Synology NAS. In removing the server from the network I realise I will need to enable ...
0
votes
1answer
228 views

Configure LAN for IPv6 with SLAAC on WAN

My ISP assigns me an IPv4 address via DHCP and an IPv6 subnet through SLAAC. I set up my pfSense box to use NAT and DHCPv4 for my LAN network which works fine. However, on the IPv6 side, my LAN ...
0
votes
2answers
127 views

Weird routing behavior between 2 Subnets

I have two Subnets and the Routing works like this: Client A can Ping (ICMP) Client B Client B can't Ping (ICMP) Client A There are no Routes manually configured in the Access Point (Google Wifi ...
0
votes
2answers
162 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
1answer
49 views

DHCP snooping - my clients dont get ip from dhcp

Why the PCs don't get ip from Core switch Dhcp pool? without dhcp snopping there is no problem, but when i enable dhcp snooping clients stoping to get ip from dhcp. This is my topology: topology ...
0
votes
0answers
107 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
0answers
29 views

dnsmasq: stuck in DHCPOFFER after 29 clients

System: Ubuntu 16.0.4.4 LTS Fresh installed dnsmasq serving clients on wifi interface via hostapd. Everything works fine until the number of clients reach 29 - 30. (checked via leases file) After ...
0
votes
2answers
73 views

Is IP address of VirtualBox instance - in saved state - kept for it?

when a Virtualbox instance is closed with save state, does the VirtualBox program/daemon still present the instance to the DHCP daemon as working, so that the current instance's IP address will be ...
0
votes
0answers
63 views

Windows DHCP server audit activation with analytical logs

I'm trying to activate DHCP server auditing logs on a Windows Server 2012 R2 using the DHCP analytical logs. Until now, I was using the former method using TXT files (see image below). This was ...
0
votes
1answer
188 views

ISC DHCP assign pool/subnet to certain MAC addresses

Hej, desperate here! I'm running isc-dhcp-server 4.1 here (with webmin but that's another topic) and want to give some options (tftp-server and bootfile) to network-components that I can identify by ...
0
votes
1answer
114 views

How does DNSMasq integrate with my router?

Context I've successfully installed DNSMasq on a Debian machine and everything seems to be working. Here's what I did: install DNSMasq with sudo apt-get install dnsmasq update file /etc/dnsmasq.d/...
0
votes
0answers
141 views

Virtualbox VM only getting IPv6 over bridge connection. How to get IPv4 address

I have launched Ubuntu16.04 in Oracle virtual box on windows 10 machine. I have used two type of adapters: NAT and Bridge Connection. The ip address on Bridge connection is getting IPv6 address and ...
1
vote
0answers
68 views

WDS ERROR on some workstations (Error retrieving network information (0x80072743))

At first I apologize for my poor English. I've installed WDS role on a Windows Server 2008 R2 and configured it with an install WIM Image of Windows 7 Ultimate x64 and its associated boot image and ...
1
vote
0answers
134 views

DHCP Server: Missing Addresses and how to free them

Our DHCP Server, running on a Windows Server 2012 R2 Data Center, shows that we have 241 addresses total with 220 (91%) in use, 21 available. If I go to the Address Leases node and count all IP ...