The DNS server's logs will usually indicate why the request was rejected. Check syslog/daemon logs for bind/named messages.

The DNS-Log said permission denied.

After giving group write permissions on /var/named the same error occured.

After disabling SELinux there was no permission denied error.

Now i receive a hardware adresse error. My dhcpd.conf is configured for 3 mac adresses only.
I gave the host to provision one of this adress, but omshell says hardware adresse conflict.

So now i habe to figure out why the dns entry fails on

/var/named/79.140.10.rev.jnl: create: permission denied

when i have selinux on and why the dhcp doesnt accept the right hardware adresse.

Here is the log from the omshell:

D, [2016-03-14T12:05:35.245050 #20807] DEBUG -- : omshell: executed - set name = "gemsvm1.gemsvm.bafg.de" 
D, [2016-03-14T12:05:35.245250 #20807] DEBUG -- : true
D, [2016-03-14T12:05:35.245345 #20807] DEBUG -- : omshell: executed - set ip-address = 10.140.79.174
D, [2016-03-14T12:05:35.245395 #20807] DEBUG -- : true
D, [2016-03-14T12:05:35.245460 #20807] DEBUG -- : omshell: executed - set hardware-address = 00:16:3e:8c:4f:                  75
D, [2016-03-14T12:05:35.245518 #20807] DEBUG -- : true
D, [2016-03-14T12:05:35.245582 #20807] DEBUG -- : omshell: executed - set hardware-type = 1
D, [2016-03-14T12:05:35.245635 #20807] DEBUG -- : true
D, [2016-03-14T12:05:35.246028 #20807] DEBUG -- : omshell: executed - set statements = "filename = \"pxelinu                  x.0\"; next-server = 0a:8c:4f:aa; option host-name = \"gemsvm1.gemsvm.bafg.de\";" 
D, [2016-03-14T12:05:35.246119 #20807] DEBUG -- : true
D, [2016-03-14T12:05:35.246201 #20807] DEBUG -- : omshell: executed - create
D, [2016-03-14T12:05:35.246311 #20807] DEBUG -- : true
E, [2016-03-14T12:05:35.279445 #20807] ERROR -- : Omshell failed:
> > > > obj: <null>
, > obj: host
, > obj: host
, name = "gemsvm1.gemsvm.bafg.de" 
, > obj: host
, name = "gemsvm1.gemsvm.bafg.de" 
, ip-address = 0a:8c:4f:ae
, > obj: host
, name = "gemsvm1.gemsvm.bafg.de" 
, ip-address = 0a:8c:4f:ae
, hardware-address = 00:16:3e:8c:4f:75
, > obj: host
, name = "gemsvm1.gemsvm.bafg.de" 
, ip-address = 0a:8c:4f:ae
, hardware-address = 00:16:3e:8c:4f:75
, hardware-type = 1
, > obj: host
, name = "gemsvm1.gemsvm.bafg.de" 
, ip-address = 0a:8c:4f:ae
, hardware-address = 00:16:3e:8c:4f:75
, hardware-type = 1
, statements = "filename = "pxelinux.0"; next-server = 0a:8c:4f:aa; option host-name = "gemsvm1.gemsvm.bafg.                  de";" 
, > can't open object: already exists
, obj: host
, name = "gemsvm1.gemsvm.bafg.de" 
, ip-address = 0a:8c:4f:ae
, hardware-address = 00:16:3e:8c:4f:75
, hardware-type = 1
, statements = "filename = "pxelinux.0"; next-server = 0a:8c:4f:aa; option host-name = "gemsvm1.gemsvm.bafg.                  de";" 
, >
E, [2016-03-14T12:05:35.280006 #20807] ERROR -- : Failed to add DHCP reservation for gemsvm1.gemsvm.bafg.de                   (10.140.79.174 / 00:16:3e:8c:4f:75): Entry already exists

Here is my dhcpd.conf:

# dhcpd.conf
omapi-port 7911;

key omapi_key {
        algorithm HMAC-MD5;
        secret "here is my secret key";
}
omapi-key omapi_key;

default-lease-time 43200;
max-lease-time 86400;

ddns-update-style none;

option domain-name "gemsvm.bafg.de";
option domain-name-servers 10.140.79.170, 10.140.79.240;
option ntp-servers ptbtime1.ptb.de;

allow booting;
allow bootp;

option fqdn.no-client-update    on;  # set the "O" and "S" flag bits
option fqdn.rcode2            255;
option pxegrub code 150 = text ;

# PXE Handoff.
next-server 10.140.79.170;
filename "pxelinux.0";

log-facility local7;

include "/etc/dhcp/dhcpd.hosts";

subnet 10.140.79.0 netmask 255.255.255.0 {
  pool
  {
    range 10.140.79.172 10.140.79.174;
  }

  option subnet-mask 255.255.255.0;
  option routers 10.140.79.1;
  host gemsvm1.subdomain.domain.de { hardware ethernet 00:16:3E:8C:4F:75; }
  host gemsvm2 { hardware ethernet 00:16:3E:8C:4F:76; }
  host gemsvm3 { hardware ethernet 00:16:3E:8C:4F:39; }
  ignore unknown-clients;
}

I think it has something to to with the host blocks and the ingnore unknown clients statement.

Why do I make this? Because not alle mac adresses are allowed in my network.
I can only provision to 3 mac adresses i got from my administrator.

Any idea to fix?

The error is in the log:

E, [2016-03-14T12:05:35.280006 #20807] ERROR -- : Failed to add DHCP reservation for gemsvm1.gemsvm.bafg.de                   (10.140.79.174 / 00:16:3e:8c:4f:75): Entry already exists

Your existing host { } entries prevent the smart proxy from adding another with the same MAC address. Try removing them, if ignore unknown-clients is still there then it should probably work fine.

Ok, it was done with creating a class and filtering the mac adresse there. So that runs.

Foreman added the host and it started, but when i want to delete the host (because there is a wrong mac adress) it says:

undefined method `delete' for nil:NilClass

how can it delete the host now?

Please provide the whole request, error and stack trace from /var/log/foreman/production.log when deleting the host.

Here is the trace:

Started DELETE "/hosts/gemsvm1.gemsvm.bafg.de" for 10.140.70.92 at 2016-03-14 12:53:35 +0100
2016-03-14 12:53:35 [app] [I] Processing by HostsController#destroy as HTML
2016-03-14 12:53:35 [app] [I]   Parameters: {"authenticity_token"=>"/grILdfaBcsOrYm8USliuMaULVKxiWpxz+mYht+aXYI=", "id"=>"gemsvm1.gemsvm.bafg.de"}
2016-03-14 12:53:35 [app] [I] Delete the DNS PTR record for 10.140.79.173/gemsvm1.gemsvm.bafg.de
2016-03-14 12:53:35 [app] [I] Delete DHCP reservation for gemsvm1.gemsvm.bafg.de-b2:b0:ce:33:5b:8c/10.140.79.173
2016-03-14 12:53:36 [app] [W] Action failed
 | NoMethodError: undefined method `delete' for nil:NilClass
 | /opt/theforeman/tfm/root/usr/share/gems/gems/foreman_salt-4.0.1/app/models/foreman_salt/concerns/host_managed_extensions.rb:98:in `delete_salt_key'
2016-03-14 12:53:36 [app] [I]   Rendered common/500.html.erb within layouts/application (4.1ms)
2016-03-14 12:53:36 [app] [I]   Rendered layouts/base.html.erb (2.0ms)
2016-03-14 12:53:36 [app] [I] Completed 500 Internal Server Error in 1521ms (Views: 10.7ms | ActiveRecord: 22.3ms)