Remote management address being changed by DNS

palitech
New Contributor

Good Morning all,
I have encountered an issue that really has all our team kind of stumped. I am not a server admin, so I apologize for mistakes in advanced.
I was trying to remote into a computer we have for purposes of testing a graphics issue. VNC gave me back the error of the computer is not found and may not be configured on the client. So I checked the Sharing preferences on the client and all was OK. I could remote in via IP address, so I know now at this point settings are configured properly. I removed the computer from our AD, and restarted the MAC and did not connect to the internet. I set the computer name, localhost, and host name all via terminal, then cleared DNS via terminal and restarted the machine again. Looking at the Sharing Preferences, the remote login and management address both have the Computer Name in the address, but as soon as I connected the ethernet cable, the remote management address is changed to another computer name(Windows PC name) on its own. I then started to ping the Computer name I set, and got no response. I then ping the name that it changed itself to, and that came back with a different IP address showing in the Networks settings. So we went to the server level and manually resolved the IP address of the Windows PC to the proper computer name of the same Windows PC, so that the Windows user would not be affected. But this still did not resolve the issue on the mac. So does anyone have any guesses or experience with this issue? Im almost positive this is not a mac issue, but does Mac's remote management address get assigned based off DNS? WINS name as well was late to resolve itself too. Two other computers had this issue that i was aware of, but seemed to be resolved over the weekend. Can we manually set the remote management address in an instance like this? Again, sorry in advanced if this doesn't make complete sense. This is what happened, and still doesn't make sense when I read it back.

8 REPLIES 8

millersc
Valued Contributor

Is DNS and DHCP being served up by Windows Server?

palitech
New Contributor

Yes they are. I also just read the article that 10.10.4 will be going back to mdnsResponder, omitting the disoveryd process. Which i know will help with some of the issues we have been having , just not sure if it will be this specific one.

millersc
Valued Contributor

I have seen what your describing with Windows serving up DNS/DHCP over many OS's. I think it's just a timing issue when the client releases the IP, the mac grabs it but the name still the previous device. Have you tried clearing cache? https://support.apple.com/en-us/HT202516
I have seen it clear up after a couple reboots.

palitech
New Contributor

Thank you @millersc i believe you are correct. Just seemed weird that it was getting its name from DNS, and not setting it on its own. I did try clearing the cache but it did not work. Perhaps a few more restarts would have done the trick. Thanks again for your responses.

htse
Contributor III

a domain-bound Windows client has the ability to dynamically update it's DNS records with the Windows DNS server (ipconfig /registerdns). However OS X doesn't have that ability. So when OS X retrieves the DHCP lease, it doesn't update the DNS records in DNS. So when it comes time to perform a reverse lookup to set the hostname, it'll pull the existing DNS record set by the Windows client.

There's an option in Windows DHCP that will allow the DHCP server to perform the DNS update for the client on behalf of the client.

You can also use Dynamic Global Hostname to perform Dynamic DNS like a Windows Client
https://support.apple.com/kb/PH18700?locale=en_US

bentoms
Honored Contributor III
Honored Contributor III

@htse Are you sure about that?

dsconfigad has a flag to restrict Dynamic DNS registration.

Which would then mean that registration does work.

htse
Contributor III

@bentoms that's an excellent point. I added a virtualized a second network controller to try it out.

The Active Directory Plug-in itself seem to doesn't handle the Dynamic DNS registration, that's still passed to the mechanism that handles the Dynamic Global Hostname pane however it granular control when of which adapters to register. I could run dsconfigad -restrictDDNS enX and it would dynamically register and unregister interfaces with DNS, but it was still dependent on having that Dynamic Global Hostname configured. If it was not set it would deregister all the entries from DNS.

donmontalvo
Esteemed Contributor II

Do we even care anymore about Host Name (HostName)? Its out of our control, and with AD administrators not caring about scavenging for stale records, its like chasing your tail. Casper Remote will find the computer (search by User Name, etc.) and send you to Screen Sharing (VNC). If you need to SSH to a computer, its easy enough to find the computer in JSS to get the IP Address.

We only care that the Computer Name (ComputerName) is correct, and that the Local Hostname (LocalHostName) matches it. We leave Host Name (HostName) alone, unless there is a reason to have to fiddle with it.

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https://donmontalvo.com