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

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pfSense - DHCP Relay

I have 3 pfSense boxes acting as routers on a single subnet (172.22.12.0/26). Router A - 172.22.12.1 Router B - 172.22.12.17 Router C - 172.22.12.33 I want Router A to be the only DHCP server. ...
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527 views

Assign two static IP addresses to one mac address

Can Isc-dhcp-server give two static ip addresses to one mac address? I have several Genexis terminals in my network. Each terminal have two interfaces, one for public traffic and one for a management ...
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85 views

Controlling 2 DHCP servers in one network

In my customer network, we have 2 DHCP servers. One is fully controlled by me and another by a different vendor. I want to make sure a set of devices (my devices) when connected, should get IP address ...
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497 views

CentOS 6.4 - Cant get an IP from DHCP

I have a Ubuntu and CentOS system running on XenServer. The Ubuntu Box gets and IP from DHCP no problem. The CentOS will not take a DHCP but a static address works fine. [root@XenCentOS ~]# service ...
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How do I protect a low budget network from rogue DHCP servers?

I am helping a friend manage a shared internet connection in an apartment buildling with 80 apartments - 8 stairways with 10 apartments in each. The network is laid out with the internet router at ...
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118 views

ISC DHCPD IPv6 for multiple interfaces

I want to assign multiple IPv6 to a server with multiple NIC. As IPv6 RFC defines, each server has a unique DUID that can have one of the 3 formats (LL, LLT or enterprise). And each NIC has an IAID. ...
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42 views

How to treat DHCP_REQUEST with xid different from the last DHCP_OFFER?

I am maintaining a custom DHCP server implementation. There is a client that consistently changes xid after receiving our DHCP_OFFER, thus, xid in its DHCP_REQUEST is different from the one used in ...
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182 views

DHCP serving has stopped working

Something happened in our server room over the weekend that had me in the office late Saturday night replacing two switches. After powering down both racks, I have an issue where none of the computers ...
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44 views

Changing from router DHCP to Server DHCP [closed]

I want to setup a Linux DHCP server instead of a router based DHCP. I'm guessing that I will need to turn off the router DHCP, but keep the router as the gateway. I think that the BCAST DHCP requests ...
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115 views

Using DHCP on virtual servers (ESXI) [closed]

I am setting up a small lab with 5 virtual servers running on VMware ESXi 5. The servers are: Network Services server (CentOS 6.4) LAMP server (CentOS 6.4) File server (CentOS 6.4) Zimbra mail ...
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46 views

BOOTP on Juniper 4200 stack works one one subnet, not another

I have a Juniper Stack that connects vlans 10,11 and 50. 10 is servers, 11 is desktops and 50 management. Bootp is redirecting DHCP requests to a AD box on 10.x just fine for 50 vlan, and worked well ...
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154 views

DHCP split-scope using Windows 2008 and Windows 2012 servers

Can I configure DHCP split scope using our current Windows 2008 server with DHCP, and a new Windows 2012 server which I have installed DHCP on?
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239 views

How to get machines to use a DNS without a fixed IP, which does not appear in the DHCP lease? [closed]

I have some machines on a network. This network has a DHCP server - which I have no control over, and no DNS server, i.e. the DHCP lease refer you to some ISP's server and do not serve IPs for local ...
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3answers
206 views

Windows 2008 Domain - DHCP on Server vs Firewall

I currently administer a Windows 2008 domain network with DHCP running on the DC. Clients obtain addresses dynamically and servers are assigned static addresses. In the case that the DC fails ...
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1answer
171 views

DHCP over PXE fails, but in the OS it works - with configured (R)STP

I'm trying to PXE-boot desktop-machines to install a new OS over the network, but it isn't picking up an IP address via DHCP during boot. When an OS is already booted on the machine, it is working ...
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2answers
277 views

how to disable RRAS on windows 2008 r2 pre-reserving blocks of IPs

I have a problem where one of the DHCP scopes has exhausted its scope of IPs. Investigating, I found that a couple of the window 2008 r2 servers were reserving blocks of IPs for RAS running on the ...
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82 views

Private DHCP through a switch using two eth interfaces?

Right now, I have an Scientific Linux blade connected to the internet on eth3, and connected to a 48 port Cisco switch on eth2. This Cisco switch is connected to the eth2 of 24 blank blades (which are ...
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92 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 ...
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1answer
99 views

What determines which of a DHCP Relay Agent's IP addresses are attached to relayed requests?

I have a vlan with multiple IPs set, and a helper-address: vlan 15 ip helper-address 172.17.1.11 ip address 172.17.5.254 255.255.255.0 ip address 172.17.51.254 255.255.254.0 All relayed requests ...
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1answer
52 views

Hi, I have 3 dhcp servers like dhcp1,dhcp2,dhcp3 in my LAN. If client send the request for ip, which server will respond & offer the ip address [closed]

I have 3 dhcp servers like dhcp1,dhcp2,dhcp3 in my LAN. If client send the request for ip, which server will respond & offer the ip address
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VLAN tags not shown in packet capture (Linux) via tcpdump

I am adding a tagged VLAN onto eth0: #ip link add link eth0 name eth0.20 type vlan id 20 This results in: #ip link 2: eth0: <BROADCAST,MULTICAST,PROMISC,UP,LOWER_UP> mtu 1500 qdisc ...
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41 views

Server connections not connecting when switching to Static IP

I have a Centos 6.4 based VM, and I'm running Virtualmin on it to host my personal site. The problem is that by default, the OS is using DHCP, even though at router level (virtual router defined ...
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371 views

Linux server not receiving default IPv6 route over PPP link

I'm replacing a pfSense router in a remote office with a small linux device, running Debian. The router only has to handle very basic iptables / DHCP and VPN facilities. It is configured so that the ...
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28 views

Hosted 2008 SBS, DNS over Site to Site VPN Issues

Been having a little bit of a headache recently with DNS over site to site VPN. We have a SBS within a hosted environment and an RDS. The SBS is of course hosting DNS for the internal domain. The ...
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1answer
37 views

Server between our office network and the internet, as wireless router and ssh tunnel [closed]

We have a small office network that today is behind a normal router connecting us to the internet. We have a web based system on the internet and we have some admin tools on it that we want to lock ...
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128 views

Windows 7 DHCP Inform/Discover packet HLen=0

After introducing a Windows 7 machine onto my network, my DHCP server began to complain about receiving DHCP packets with an invalid mac length. It did not take very long to figure out that once ...
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2answers
127 views

IP Alias and port bridging

The situation is that I have an Ubuntu box with multiple ethernet ports, which I'd like to behave as if connected to the computer through a switch. I can achieve this easily with a bridge. In ...
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2answers
109 views

multiple (required) dhcp servers causes network problems in public library

A client of me asked me for helping with a network problem. The client in question is a public library. The problem: The library provide wireless internet access to the guests via an all-in-one ...
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44 views

Multiple DNS mappings for a host via DDNS

I have a network in which DNS is automatically updated with a record for hosts when they get an address via DHCP (isc-dhcp-server & Bind configured with DDNS updates). The DHCP server is ...
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59 views

Where can I download the dhcpd3-server source code? [closed]

could you tell me where I can find the source code for dhcpd3-server? I know I can find the ready packages for Ubuntu/Fedora but I need to download the source code so I can..study it Thanx in advance ...
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79 views

DHCP is assigning existing static ip

I have some devices such as QNAP NAS drives and a computer that is not part of the domain connected to our network. I have assigned a static IP to these devices. Sometimes I find that the windows DHCP ...
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980 views

Hyper-V: Guest external internet access

Following setup: Host machine has 1 physical NIC Host OS = Win Server 2008 R2 (hosted in data center) Guest OS = Win Home Server 2011 Network setup basically as described here or here. Goal: ...
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50 views

DHCP interaction with DNS

I am playing now with DHCP and DNS, particulary with dynamic secure updates. As I understand it is used to allow only AD-authenticated users to register their DNS records. But the question is - if I ...
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1answer
49 views

DHCP and static IP

I have a server that dishes out IP addresses from 192.168.1.100 to .254. I then have a linux client that must be assigned on 192.168.1.150 for a few days (this is done in the eth0 network script. If ...
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123 views

Can't obtain ip-addres from my DHCP server

I can't obtain a ip-addres from my dhcp-server and it's going trough a firewall (pfsense), The firewall(pfsense) and DHCP server are two virtual machines on my physical server(ESXI). As rules i use ...
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1answer
67 views

DHCP server not assigning IPs - Linux (CentOS)

I am having a main issue with the DHCP server. It is not assigning IPs and the dhcp.leases file is increasing in size as it is logging multiple entries for same IP. Started and stopped the service ...
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2answers
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I turned off server 2012 which host my dhcp server but computers on the network still getting ip addresses

I have a DHCP server installed on Win Server 2012 which is turned off right now, but my computers still can establish online connections with the IPs previously received from the DHCP server. I tried ...
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39 views

Avoid connect 2nd DHCPs on 1 LAN [closed]

I have a LAN network using Draytek 2910 with DHCP. The network goes through 20 different rooms. At first everything is working good. Suddendly the network keep losing IP addresses every 30 t0 60 ...
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1answer
631 views

Understanding DHCPv6 Stateful Solicit message

I have been reading the full RFC 3315 and trying to generated spoofed nodes to ask for IPv6 address. (only for practice) Right now, I have a Ubuntu with wide-dhcpv6-server (the DHCPv6 server), one ...
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1answer
431 views

Debian hangs on startup (NFS Common utilities: statd)

I am trying to configure my debian 6 machine to use DHCP. I have modified the /etc/network/interfaces to only contain: auto eth0 iface eth0 inet dhcp But when I reboot it hang at NFS Common ...
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1answer
198 views

determining gateway ip in dhcp server in case of relay agent existence

I've got a situation where i have two subnets. (Say subnet 1 and subnet 2). ` My DHCP Client is configured inside subnet 1 (net id : network id 10.1.1.0) My DHCP Server is configured ...
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DHCP snap-in crashes when I select IPv4

When trying to use the DHCP Snap-In remotely from my Windows 7 desktop, it crashes when I select IPv4. This only happens for certain servers, but works fine for other servers. All servers are Windows ...
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1answer
611 views

Configure DHCPD with assigned IP address and gateway on different subnets for KVM [closed]

I have a dedi with an IP range of 123.123.123.1/24, the problem is the gateway address: 111.111.111.254 and it's on completely different subnet. I have already setup a bridge and KVM virtualization. ...
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422 views

Can I see DHCP options on my network from a windows client? [closed]

Is there anyway to see the DHCP options configured on the server from a windows client (win 7) with no login / admin access to the server?
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751 views

Inconsistent dynamic DNS update behavior

After having upgraded a Windows Server 2003 Active Directory Domain to Server 2008, and upgraded client PCs from Windows XP to Windows 7, I'm seeing inconsistent dynamic DNS update behaviour. Two ...
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36 views

AD Server Connection Probem

Ok so i have a Linux server handling the DHCP, and FTP server i have and Network Shares. Then i have a Server (Windows R2) with just the AD. None of the client computers can connect to the Domain. The ...
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1answer
113 views

DHCP-defined local DNS address isn't responding [closed]

I set up a bind DNS server on 10.0.0.2 on my network. named.conf looks like this: options { directory "/var/named"; pid-file "/run/named/named.pid"; auth-nxdomain yes; ...
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1answer
73 views

Trying to install new wifi router, continually losing its gateway, sometimes crashing entire network [closed]

So, I'm trying to set up a buffalo router with dd-wrt loaded stock, If I leave the settings alone, the router loses its default gateway each time, and the router admin back-end is never accessible ...
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1answer
137 views

How do I resubnet my network [duplicate]

Our DHCP is running out of addresses. I cannot extend the range and would like to resubnet. Right now our addresses are: 10.1.24.1-254 255.255.255.0 Would I change the subnet to 255.255.254.0 ? ...
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1answer
67 views

Client doesn't get new IP when switching between subnets/locations

So here is our setup. We have 14 locations each with its own subnet and router. The routers at these locations have DHCP relay enabled that points back to our central server that is running DHCP. ...