DNS Resolution Problems

[cpguru21]

I am having DNS resolution issues with any of the macs on my network that Ventura and newer (as near as I can tell).

I am running a windows server environment, but DNS is running on a linux VM. All server side is running on VM. DHCP is handed out by my firewall.

DNS1:172.16.1.60
DNS2:172.16.1.61

1) HOST file seems to be ignored? Manually entering in an entry the mac host file seems to make no difference on whether the mac can resolve the fqdn of a server.
2) Flushing DNS cache does not resolve the issue.
3) Ive made sure private relay is off (this has caused an issue in the past)

I can ping the ip of the dc. I cannot ping the fqdn of the dc (or my remote desktop server, which is serving an app). An iMac right next to the problem mac (running pre ventura os) can ping fqdn no problem.
nslookup reveals that the offending mac is using the correct dns server and produces the exact same results as the mac that is working. IE it querries the dns server just fine and gets the proper results back.
dig also shows that we are indeed querying the correct servers as well and returning the proper dns server.

I am pulling my hair out with this one. I've worked with macs for a long time and most issues (especially network related) I can resolve.

Am I missing something basic here?

I was forced to bypass dns and manually program ip addresses into the rds clients to get them to work because the offending systems could not find the server.

 

[bogdanw]

1) HOST file seems to be ignored?

"Safari ignoring hosts file?" https://forums.macrumors.com/threads/safari-ignoring-hosts-file.2445512/

 

[cpguru21]

"Safari ignoring hosts file?" https://forums.macrumors.com/threads/safari-ignoring-hosts-file.2445512/

Well that is also a problem but it is not just a safari issue. We are using remote desktop - or - windows app to access an rdp server.

I simple ping from terminal shows that the system does not resolve the fqdn. an nslookup of the fqdn shows the correct response and correct dns servers, however the mac just will not resolve it.

I've found no resolution to this issue with these select imacs and had to resort to using the static ip of the server.

If anyone has any insight or possible directions to go in, I would greatly appreciate it.

 

[cpguru21]

To add to the bizarre scenario, if I statically assign the dns server (the same server that is displayed as the top dns server in the dns list) then it resolves. So is this a dhcp issue???

 

[BigBlur]

To add to the bizarre scenario, if I statically assign the dns server (the same server that is displayed as the top dns server in the dns list) then it resolves. So is this a dhcp issue???

Did you check that both DNS servers are able to resolve the FQDN?

Run these commands from the machine that is having issues:
nslookup [FQDN] 172.16.1.60
nslookup [FQDN] 172.16.1.61

I don't think it's a DHCP issue. If you run the nslookup command without specifying the DNS server, it'll show you which one it used...which sounds like what you may have done in your earlier post, so I'm guessing it got set correctly through DHCP.

If those commands are working fine, then maybe need to back up a step and tell us what the main problem is. Sounds like the RDP app isn't able to connect...are there any settings in there that need to be changed? Are you getting any certain errors? Are you using the same version of the app on both machines?

 

[cpguru21]

Yes checked nslookup for both dns servers and it resolves so not sure what to do.

:nslookup cota-rds01.cotaoil.server 172.16.1.60
Server: 172.16.1.60
Address:172.16.1.60#53

Name: cota-rds01.cotaoil.server
Address: 172.16.1.54 <---(correct ip)

But then ping cota-rds01.cotaoil.server and message that it cannot resolve.

BUT

On the mac, if I go into the wifi settings and then manually put the dns server in ther with the add button, it will then resolve.

Weird. Apple voodooo.

 

[cpguru21]

Did you check that both DNS servers are able to resolve the FQDN?

Run these commands from the machine that is having issues:
nslookup [FQDN] 172.16.1.60
nslookup [FQDN] 172.16.1.61

I don't think it's a DHCP issue. If you run the nslookup command without specifying the DNS server, it'll show you which one it used...which sounds like what you may have done in your earlier post, so I'm guessing it got set correctly through DHCP.

If those commands are working fine, then maybe need to back up a step and tell us what the main problem is. Sounds like the RDP app isn't able to connect...are there any settings in there that need to be changed? Are you getting any certain errors? Are you using the same version of the app on both machines?

No. It is not just the rdp app that cannot connect. I posted above that you also cannot ping the fqdn of the rdp server, or any of my internal servers FQDN.

"Tell us what the main problem is"
RDP software (called Windows App) cannot find the server the connection is configured with. The day before it could just fine. This is not the first time Ive had this happen only with certain macs on the network. When I start to troubleshoot I find that the systems cannot resolve the FQDN (which is configured in the connection). No matter what I do, even though DHCP is handing down the proper dns servers and all is configured properly. The older mac os's on the network do not have this problem and have no problem resolving the FQDN.

I mentioned the host file because when this problem first arose a year or so ago, I figured I would just edit the host file since the system is supposed to look there first, prior to querying the DNS server, however that did not work.

Only 2 things have ever worked to get these systems connected:
1)stop using FQDN and use the static IP of the server. It will never change but does remove some flexibility.
2)manually enter in the same DNS servers that DHCP is handing down.

Then *poof* the systems can magically resolve the FQDN. However I should not have to do that. Something is hosed on the newer OS.

BTW resolution to the outside world (safari etc... which you mentioned above) works just fine in these scenarios. It is only the local resources.

 

[BigBlur]

Are the problematic Macs running Sequoia or Tahoe? If so, check to make sure Windows App has access to the local network.

Control access to your local network on Mac

On your Mac, allow apps to find and communicate with devices on your local network.

support.apple.com

This person said they need to toggle that setting off and back on after every reboot.

Issue on MacOS 15 with Windows App (RDP) connection - Microsoft Q&A

We have found an issue with failing RDP connections from the Windows App on MacOS 15 computers. This issue occurs on multiple MacOS 15 devices of various models. When the computer boots, in the System Settings > Privacy & Security > Local…

learn.microsoft.com

 

[cpguru21]

Are the problematic Macs running Sequoia or Tahoe? If so, check to make sure Windows App has access to the local network.

Control access to your local network on Mac

On your Mac, allow apps to find and communicate with devices on your local network.

support.apple.com

This person said they need to toggle that setting off and back on after every reboot.

Issue on MacOS 15 with Windows App (RDP) connection - Microsoft Q&A

We have found an issue with failing RDP connections from the Windows App on MacOS 15 computers. This issue occurs on multiple MacOS 15 devices of various models. When the computer boots, in the System Settings > Privacy & Security > Local…

learn.microsoft.com

Yes fantastic observation!!

This was one of the first things I checked and sadly yes it has the proper access.

The toggle has not been my experience however it is worth a try!! I will test and report back. My guess is it will not make a difference. I am basing that guess off the fact that if I manually add the same dns servers pushed by dhcp, everything works.

 

[Brian33]

Maybe this could help your troubleshooting. My imperfect understanding is that nslookup and dig do not replicate how (most? some?) apps do DNS lookups. Rather, one should use dns-sd with the -q option.

From the dns-sd man page (emphasis mine):

The dns-sd command is a network diagnostic tool, much like ping(8) or
traceroute(8). However, unlike those tools, most of its functionality is
not implemented in the dns-sd executable itself, but in library code that
is available to any application.

I have had situations in the past where nslookup and dig would give results different from dns-sd.

 

[cpguru21]

Maybe this could help your troubleshooting. My imperfect understanding is that nslookup and dig do not replicate how (most? some?) apps do DNS lookups. Rather, one should use dns-sd with the -q option.

From the dns-sd man page (emphasis mine):


I have had situations in the past where nslookup and dig would give results different from dns-sd.

Thanks for the additional tips!! I will test and report back. For now I had to just statically configure the Windows App (and any other local lan connections) on the problem computers instead of using FQDN. But thanks for the additional test commands!!!