Appendix A: Troubleshooting DNS

Troubleshooting DNS

This appendix provides some steps to perform to ensure that you have the correct MC information configured in your DNS server.

Note: These instructions apply to the Windows platform.

The procedure shown below checks that you have a DNS A record that maps the MC's host name to its IP address for forward lookups, and a DNS PTR record that maps the MC's IP address to its host name for reverse lookups. In addition, it checks that a DNS SRV record for _bootstrap-pcoip exists, and that the DNS TXT record containing the MC's certificate fingerprint exists and is located in the right place.

Please note:

DNS records have a time-to-live value that dictates how long the records are cached. If your nslookup results show old information, please try clearing the PC's DNS cache using the ipconfig /flushdns command before running the nslookup commands in this example again. E.g.,
C:\Users\username> ipconfig /flushdns
Windows IP Configuration
Successfully flushed the DNS Resolver Cache
PCoIP Zero Client endpoints will cache DNS results for the entire time-to-live period. You can clear this cache by power cycling the device.
The SHA-256 fingerprint shown below is the default MC certificate fingerprint. If you have created your own certificates, this value will be different.
The example below uses sample IP addresses and host names for the primary DNS server and MC. Please substitute your own server and MC information for these names and addresses.
The information returned by the nslookup commands is shown below in grey text after each command.

To verify DNS MC information:

Log in to your Windows server.
Launch a command prompt window by clicking the Start button and typing cmd in the Search box.
Launch nslookup from the command line prompt:
C:\Users\username> nslookup
Default Server: mydnsserver.mydomain.local
Address: 172.15.25.10
Instruct nslookup to connect to the DNS server under which you created the records. This address should match the primary DNS server address configured in the endpoint's network settings.
> server 172.15.25.10
Default Server: mydnsserver.mydomain.local
Address: 172.15.25.10
Enter the FQDN of your MC to perform a forward lookup to verify that a DNS A record that maps the MC host name to its IP address is present:
> pcoip-mc.mydomain.local
Server:   mydnsserver.mydomain.local
Address:   172.15.25.10
Name:   pcoip-mc.mydomain.local
Address:   172.25.15.20
Enter the MC's IP address (found in the above step) to perform a reverse lookup to verify that a DNS PTR record that maps the MC IP address to its host name is present:
> 172.25.15.20
Server:   mydnsserver.mydomain.local
Address:   172.15.25.10
Name:   pcoip-mc.mydomain.local
Address:   172.25.15.20
Set the record type to SRV and check that a DNS SRV record exists to tell endpoints the FQDN of the MC. In the second command, the domain name is the domain under which your endpoints are configured:
> set type=srv
> _pcoip-bootstrap._tcp.myendpointdomain.local
Server:   mydnsserver.mydomain.local
Address:   172.15.25.10:
> _pcoip-bootstrap._tcp.myendpointdomain.local    SRV service location:
             priority     =0
              weight      =0
              port           =5172
              svr hostname   =pcoip-mc.mydomain.local
pcoip-mc.mydomain.local      internet address = 172.25.15.20
Set the record type to TXT and check that a DNS TXT record exists containing the MC SHA-256 fingerprint. In the second command, the domain name is the domain under which your endpoints are configured.
> set type=txt
> pcoip-mc.myendpointdomain.local
Server:   mydnsserver.mydomain.local
Address:   172.15.25.10
pcoip-mc.mydomain.local     text =
        "pcoip-bootstrap-cert= B7:62:71:01:85:27:46:BB:E3:E9:5C:E2:34:2C:B5:76:7D:7A:F1:
7F:6A:4D:5C:DB:AA:2B:99:BD:D5:A9:28:91"
Exit nslookup:
> exit