12
votes
DHCPDISCOVER/DHCPOFFER, but no DHCPACK
Supposing your DHCP-server and DHCP-client are both connected to the same ethernet segment, and supposing such ethernet segment spans several L2-switches interconnected with various "trunk" (802.1q) ...
- 3,998
8
votes
How to ignore a set of Mac addresses in dhcpd.conf?
From this thread on the mailing list, another option to block specific hosts is:
class "black-hole" {
match substring (hardware, 1, 6);
# deny booting;
ignore booting;
}
subclass "black-...
- 181
6
votes
DHCPDISCOVER/DHCPOFFER, but no DHCPACK
Had the same issue. Not seeing any DHCPACKs. Problem here was:
disk full
dhcpd could not write to /var/lib/dhcp/dhcpd.leases.
- 69
6
votes
Accepted
ISC DHCP Server listening on virtual interface
OK, I figured it out. If you have more than one IP address assigned to the same interface, then all the subnet declarations have to be grouped together into another declaration. For example, the Linux ...
- 181
5
votes
ISC DHCP Server "Dynamic and static leases present"
The error says it all, you have both static and dynamic lease present for the same ip address range.
In the following you have defined a dynamic lease:
# Bekannte Geraete
pool {
range 192....
- 8,941
5
votes
Accepted
windows machine gets assigned wrong netmask
Probably a typo: option subnet-mask 225.225.225.0; Not a valid mask :-)
- 35k
4
votes
ISC DHCP infinite lease time
I would suggest specifying lease times in seconds. So where:
default-lease-time 600; This being ten minutes
max-lease-time 7200; This being two hours
try:
default-lease-time 86400; This being one ...
- 59
4
votes
Accepted
Can I prevent Debian from hitting DHCP server twice during installation?
The first DHCP DORA (Discover, Offer, Request, Accept) sequence is triggered by the client PXE firmware trying to find an IP/MASK and the PXE data (NBP + TFTP location).
The PXE firmware then TFTP ...
- 3,409
4
votes
Can I request a specific IP address via DHCP without rejecting an offer of a different address from the DHCP server?
Use the lease block instead. From trial and errors, this configuration block is ignored from the dhclient.conf file but used in the leases file (default /var/lib/dhcp/dhclient.leases unless overriden ...
- 9,670
4
votes
Can't start isc-dhcp-server because of the Error : Not configured to listen on any interfaces
dhcpd needs 2 files to work:
/etc/default/dhcpd.conf -- defines the interfaces(what you are missing)
and
/etc/dhcp/dhcpd.conf -- the file you have already finished up
the contents of /etc/...
- 41
3
votes
How do i keep ISC-DHCPD from offering different IPs when there is two requests from the same MAC
You can get it with the ignore-client-uids flags. It is included since the 4.2.0 version of isc-dchpd :
Add this line:
ignore-client-uids true;
ignore-client-uids flag;
If the ignore-...
- 131
3
votes
configure a dhcp server to serve two different scope on the same subnet with multiple interfaces
You defined wrong network mask at, that's why dhcp server is failing to start
iface eth1 inet static
address 192.168.0.1
netmask 255.255.255.0
iface wlan0 inet static
address 192.168.0....
- 357
3
votes
split dhcp subnet in two parts
Your configuration should look more like this:
subnet 1.2.3.0 netmask 255.255.255.0 {
range 1.2.3.128 1.2.3.254
next-server 1.2.3.199;
filename "pxelinux.0";
option routers 1.2.3.1;
option ...
- 23k
3
votes
Accepted
Block DHCP clients based on strings in hostname
It sounds like you're after the dhcp-client-identifier field, which may or may not be what you call the hostname. According to dhcp-eval(5), there may be a regex option available. If so,
class "iBan" ...
- 1,636
3
votes
Accepted
isc dhcp class with more match
I haven't been able to test it myself, and the DHCPD.conf man page isn't that great, but you could try something like the following:
match if ( substring(hardware,1,3) = 00:01:e6 ) or
( ...
- 5,351
3
votes
Windows 7 Client flooding network with DHCP requests. Not setting IP
Seem to me a bad NIC in the workstation.
Try a firmware update and if it still don’t work change the NIC.
- 16.5k
3
votes
isc-dhcp-server doesn't start automatically
I use Ubuntu Server 18.04 and I was facing a similar problem: the isc-dhcp-server won't automatically start. For me, it turns out the problem was that the service was disabled; executing sudo ...
3
votes
Accepted
ISC-DHCP-SERVER adding incorrect reverse zone entry
In my DHCPd configuration file, I put the reverse zone as 168.192.in-addr.arpa, which is incorrect. It needs to simply be in-addr.arpa.
ddns-rev-domainname "in-addr.arpa.";
After changing that, and ...
- 885
3
votes
Accepted
How do I purge dhcpd.leases?
From the manual man dhcpd.leases:
In order to prevent the lease database from growing without bound, the file is rewritten from time to time. First, a temporary lease database is created and all ...
- 74k
3
votes
DHCP Pools on Ubuntu DHCP server not working properly
The problem lies in the use of the hardware filter.
The documentation states that:
The hardware operator returns a data string whose first element is the type of network interface indicated in packet ...
- 562
2
votes
Monitoring an ISC DHCP Failover Status Using Nagios
For monitoring a failover setup, I would use OMAPI commands (eg. via omshell) to check the status of the failover-state object.
Considering you have properly configured your dhcpd server to enable ...
- 21
2
votes
Iptables - Allowing only a single dhcp (relay) client
It doesn't work on pure IP-level, one needs to know how DHCP does work:
At first, the DHCP client does send a packet (DHCPDISCOVER) from 0.0.0.0 to 255.255.255.255 (the local broadcast address).
The ...
2
votes
Accepted
Is it possible to set a dhcp option 77 value in vsphere as a config parameter so vNIC ROM (e1000/vmxnet3) uses it during PXE?
iPXE approach is really a cowboy hack. The answer to your question is "No"; do not expect any standard PXE client (including VMware PXE ROMs) letting you set any DHCP option.
Edit:
NIC boot-roms ...
- 3,409
2
votes
Unknown network segment - isc-dhcp-server
The configuration was OK all along. The problem was with "ghost process". I dont know how that happened, but I ran two dhcpd processes and the first one was really old... from the time when the subnet ...
- 63
2
votes
Force isc-dhcpd to disregard client hostname in ddns updates
I had the same problem and came up with the solution to add ddns-hostname to the host config.
use-host-decl-names neither ignore client-updates change any behavior of the dhcpd.
The following ...
- 21
2
votes
Block DHCP server from other network
Seems that you're trying to operate 2 IP networks over the same physical links without any logical separation between then (VLANs).
If your router doesn't support VLAN tagging, the only way to make ...
- 969
2
votes
DHCPv6 not working when UFW is enabled (Ubuntu 16.04 LTS)
I see an existing rule for a DHCP client:
# allow dhcp client to work
-A ufw6-before-input -p udp -s fe80::/10 --sport 547 -d fe80::/10 --dport 546 -j ACCEPT
I think you need to reverse the source/...
- 121
2
votes
Accepted
dhcp 'next-server' outside broadcast domain, without using ip helpers(aka dhcp relay)
in a PXE environment is perfectly doable.
in a BSDP environment (PXE for Macs) the game is different; the BDSP client broadcasts its first request and expects a list of possible booting images, the ...
- 3,409
2
votes
Accepted
Defining a new location for syslinux configuration files when setting up PXELinux
Note that the configfile is relative to the pathprefix:
if option arch = 00:00 {
option pxelinux.configfile "common.cfg";
option pxelinux....
- 3,409
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