Jump to content
Welcome to our new Citrix community!
  • 0

App Layering image being assigned Static DNS IP's

Ross Faverty1709158252


After updating our ControlUp agent we noticed that the agent was reporting DNS errors in the console on our PVS vm's only (MSC vm's are fine). Upon further inspection our PVS VM's were showing as being configured with old statically assigned DNS IP's. 


I added a version to one of our pvs vdisks and corrected the issue (set to obtain DNS IP's automatically) rebooted to make sure the changes stuck but it reverted back to statically assigning the old DNS IP's. After hours I switched the same vDisk to private mode and made the same change, rebooted and the old IP's were showing again after the reboot. 


I then made the below changes while the vdisk was in Private mode (load balancing turned off):

1. Backed up the registry (saved on the desktop).

2. Searched the Registry for values = old DNS IP's and deleted them (kept searching until no more entries were found (found 4 in total).

3, ipconfig /dnsflush

4. ipconfig /registerdns

5. ipconfig /release

6. ipconfig /renew

7. netsh winsock reset

8. netsh int ip reset

9. Confirmed IPv4 properties were set to Auto Obtain IP's and DNS IP's

10. Reboot


OLD DNS IP's are back! 


Changes were being saved as the registry backup was saved on the desktop between reboots and when searching the registry for the old IP's 2 of the deleted values were back.


I created a new version of our PVS platform layer and found it to be configured with the old dns IP's statically assigned. I made the same changes above, shutdown to finalize and published a test template with the new platform layer. No change - same issue. 


I looked at the OS layer every thing is fine in there (the same OS layer is in use in our MCS images as well and they dont have this problem so i doubted I would find anything here anyway).


I then created a brand new platform layer for PVS, published an image with just the OS & new platform layer.......old DNS IP's are showing. So even with two layers that have 0 references to the old DNS IP's when published still bring in the old statically assigned DNS IP's. 


I'm 99% sure its not the BDM disk as in the boot disk summary at startup the correct (new) DNS IP's are showing. 


The only other difference between the MCS & PVS images is that the VM's are on different hypvisors. MCS = ESXi 6.0 and PVS = XenServer 7.6


At this point I have no idea where to go next. I have opened a ticket with Citrix App Layering in the mean time. 

Link to comment

8 answers to this question

Recommended Posts

  • 1

To further clarify;


Right-Click Provisioning Services Console (top of the directory tree in the PVS Console) - Create Boot Device is the location of where the BDM Disk/Partition gets configured. From here you can burn it to an ISO if you wish. When you right click on a powered down VM from within its device collection and select "Update BDM Partitions" it pulls from whatever is configured under the "Create Boot Device" setup (a very misleading title). 





  • Like 1
Link to comment
  • 0

I published an OS template and an OS & Platform Layer template directly to the XenServer Hypervisor and there was no issue. The DNS IP's were being obtained automatically and were getting the new IP's.


Then I created a new PVS connector and published the OS and new platform layer then tested. The old IP's were once again being assigned to the VM's. So it would appear to be a PVS issue at this point rather than an App Layering issue.

Link to comment
  • 0

I am guessing, since I am still learning PVS.. Could this be a GPO, other policy, bootstrap configuration issue or is the wrong DHCP server being contacted by the TD? It might be beneficial to have the streaming, boot process captured by CDFControl, CDF trace and, or procmon, since you can readily replicate the issue.

Link to comment
  • 0



Issue appears to be VM specific. I can publish an OS & Platform Layer directly to the hypervisor and there are not IP's getting statically assigned. I can run the same vdisk to multiple vm's in the same device collection and get a mixture of the DNS IP's being statically assigned and dynamically. There does not appear to be a pattern in terms of VM host or which PVS server is streaming the vDisk. The same VM's will always behave the same. Its not GPO - this is one of the first things we looked at. 


More troubleshooting planned - good call on Procmon! 

Link to comment
  • 0

That is correct, it is certainly a PVS configuration issue. We found that once we update the target device BDM options issue gets resolved.

That is because when we do that it fetches the DHCP options those are configured on DHCP server and are updated in the BDM ISO.

Once we update the BDM properties of the target it fetches the DNS options configured on DHCP server.


DNS Option : 006 and we could verify that the IP address configured here under DNS options is same that we get if we run Boot device manager.


Hence updating the BDM properties for target is doing the same for us i.e. fetching the details of DNS server from DHCP.



Link to comment
  • 0

Dude. Thank you. OMG I've been looking for where these stupid DNS settings were coming from for DAAAAAAAYS and Citrix Support set my case to a low severity level so I can expect someone to dive into the issue sometime between now and the rapture. I am going to link to this discussion in the discussion post I made about this exact problem. Ross, thank you for posting your solution, you glorious SOB. ❤️ 

Link to comment

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Create New...