We build a set of virtual appliances used throughout the company. The networking on the VM is set to NAT to prevent external DNS records from being created, unfortunately at least once a month someone switches it to bridged so other people can connect.
The problem with this is they all have the same hostname, as soon as the external DNS record is created everyone is routed to this new address causing issues until we track down the culprit and change it back to NAT or change the hostname.
Is there a method in a 2008 R2 AD environment to blacklist a hostname and prevent a DNS record from being created? DNS is configured so a record can be created by anyone with a network device which makes it messy. Adding an A record pointing to 127.0.0.1 won't work as people work with the VM from outside it with a client.
This is a multi-domain environment and the root domain has DNS restricted, if there's a way to force the VM to request a DNS record in that space that could work.
Edit: To clarify, the DNS record is created via DHCP
Create static host records for those required, then set the permissions to them to deny writes. That should prevent them from being updated.
Related
I currently have a linux virtual machine that is setup with my school, using one of my school's domains. I recently bought a domain with GoDaddy, and I am interested in switching my virtual machine over to my domain. I'll be honest, I don't really know the first thing about configuring a DNS.
On the VM already, I have the apache server setup, so I know it is properly connected to the web using the domain I was given by my school.
Obviously, I know I'll have to change some of the basic stuff like the /etc/hosts file to switch to the new domain, but what else will I have to do in order to get my VM switched to the new domain? Thank you.
All you need to do is, add DNS records to point to the VM.
First create a DNS zone file with the provider from where you bought a domain.
Go to dns settings, create a A record and point it to the VM by adding the IP address of the VM.
Once this is done, wait for the TTL you have set, and now you should be able to access the VM from the domain.
The other day I was trying to RDC from my work laptop to work desktop using my PC's hostname but it could find the desktop. Later on I tried with my desktop's IP which worked. Both the time I was on premise and was connected to the network physically.
I could RDC every other computer in our network.
After my research, I checked firewall was disabled, flushed and re-registered dns etc. Everything seems to be in order. However, when I tried to do reverse DNS lookup it didnt work for my desktop.
After that my IT guy and I checked everything on the AD server and there was no entry for my hostname or the IP. So we manually added the dns record which didnt work either.
Following is the note from IT:
AD / DHCP on a server on a different subnet DNS on another server on
the above subnet
The Pc is on a VLAN again different subnet. The Cisco Switch controls
the VLAN but talks to DHCP server for scope
Even adding the A host on forward lookup manually can’t resolve using
hostname for ping / mstsc. Both work for IP so deff DNS issue.
Tried to ipconfig /release and renew after giving a different PC the
IP address that was originally assigned to this one thinking it would
force DNS to update.
There is no entry for the IP or the Hostname in DNS even when the IP
changed after a renew. The firewall on the PC is off. However there is
the entry in the DHCP address lease table.
Tried flushDNS and ReregisterDNS.
If anyone could point me to the right direction here I would be grateful. Also, if you need further information please let me know.
Thanks
This is not the correct forum for this question. However, I can point you in the right direction.
Your correct that this is a DNS issue (so it seems).
The entry that is missing is from the host you are trying to reach (not the client that your trying this from).
Make sure all of the systems are using the same DNS servers. Make sure the DHCP Client Service is running (even if IP address is hard coded) as that is what actually records the the host name and IP address in DNS.
It sounds like you have the routing set up or you would not be able to do it by IP address.
Is the DNS zone in AD set up to allow dynamic updates? Do you have the domain name being sent out via DHCP?
Windows will (but not always) try to find a host by DNS and will fall back to a broadcast for the PC name. This might be why it works from one VLAN, and not from another.
As a training purpose for school I would like to install an Active Directory with an external DNS.
Serveur A : WS2k16 - Role: DNS
Serveur B : WS2k16 - Role: ADS
Is it possible to do it this way?
Thanks in advance for your help
Hosting DNS somewhere other than a domain controller (DC) is a valid configuration - one that is not uncommon in large enterprise environments. I often use ISC BIND to provide DNS for our Active Directory environment, and I've occasionally used stand-alone Windows DNS servers to host the DNS service. You lose some of the "magic" that Microsoft has added to their AD/DNS integration (e.g. AD-integrated DNS has hostnames replicated to all domain controllers for redundancy), but both DNS and AD function properly.
Provided the DC can made dynamic updates in the appropriate zones (e.g. _msdcs.domain.ccTLD), all of the host records AD needs get set up for you when you're using an external DNS server.
Even if the zones are not set up to allow the DC to make dynamic updates, the DC has a file in %systemroot%\system32\config\netlogon.dns which contains the records that need to be manually created. Clients won't be able to use the domain until the DNS records are manually created, you've got the potential for something to change on the DC and require a manual update, and IIRC there are event log entries on the DC every reboot complaining about the failure to auto-register records. The configuration is not ideal, but it does work.
Using netlogon file solved the problem, many thanks.
I can now register new computers on the ADS.
Anyway the ne computer are not inserted in the DNS entries, any clue how to solve it?
For automation purposes, a script running on a Windows server needs to be able to securely update a record in AD-integrated DNS when a certain condition is triggered.
This pertains an A record for an application, which is not the hostname of the Windows server on which the script runs.
The DNS entry has an ACL in the DNS zone to allow write by the service account running the script, and the GSS-TSIG DDNS update can easily be triggered from Linux/UNIX using a DNS client (eg. 'addns') that supports secure DDNS updates for arbitrary records in the DNS zone.
On Windows, I have had no luck so far finding any DNS client that supports GSS-TSIG (secure DDNS updates) for arbitrary records in DNS. All examples point to 'Register-DNSClient' or 'ipconfig /registerdns', which appear limited to registering the record for the local machine's hostname in the DNS zone.
I attempting to deploy a Windows VM in Azure that will be running DNS for resolving a private zone in my VNet. I have created the VNet and set the IP address of the VM as the DNS server for the VNet. Since I have configured the VNet with a private DNS server, the VM gets the placeholder suffix of reddog.microsoft.com. I install DNS on the VM and create my forward and reverse zones. Since the VMs in the VNet will not be domain joined, I configure DDNS to allow unsecure updates. Outside of manually registering a record for the VM running DNS, I am unable to get it to register records. When I try to change the DNS suffix on the NIC, as soon as I click OK on the NIC properties window, my connection is killed and I am no longer able to get back into the VM. The only thing I can do at this point is to destroy it and start over. What am I missing here? Will I have to manually register records for anything I put into the VNet?
Update
From this document about Name resolution that uses your own DNS server:
When you are using Azure-provided name resolution, Azure Dynamic Host
Configuration Protocol (DHCP) provides an internal DNS suffix
(.internal.cloudapp.net) to each VM. This suffix enables hostname
resolution because the hostname records are in the
internal.cloudapp.net zone. When you are using your own name
resolution solution, this suffix is not supplied to VMs because it
interferes with other DNS architectures (like domain-joined
scenarios). Instead, Azure provides a non-functioning placeholder
(reddog.microsoft.com).
It says that your custom DNS suffix is not supplied to VMs because it interferes with other DNS architectures (like domain-joined scenarios). Moreover, Azure doesn't have the credentials to directly create records in your DNS servers. Azure leaves the primary DNS suffix blank, and you can set the suffix in the VM as the picture below:
After changing the DNS suffix, you will restart the VM, then you will see a new DNS suffix in the DNS Suffix Search List in the output of prompt commands.
Go to the DNS server, you will see the DNS records updated. Before this, make sure you have enabled the Nonsecure and secure of the Dynamic updates in the zone properties.