Cannot ping ESX hosts by hostname

[JLogan2016]

I have a 6.5 lab I am setting up, and am running into problems. I am hoping it is something simple stupid I am missing, as everything works as expected in my 6.0 lab. Basically I set up four ESXi 6.5 hosts, set up static IP addresses and reverse lookup, and joined to the domain. From the ESXi host I can ping the domain controller, and resolve the FQDN of the host itself. From the DCs however, I can only ping by IP, I cannot resolve hostname. I have cleared DNS cache, restarted management on the ESXi host, etc. Also, if I connect to the host via Putty I can resolve the hostname of the DC, as well as every other ESXi host by name. I cannot think of why I can ping by IP but not resolve by name. Any suggestions are welcome.

[daphnissov]

It sounds like you have DNS resolver issues from your DC. Have you verified that name lookups are failing with nslookup? If they are, are you certain the DNS server to which it is pointed is correct?

[JLogan2016]

So, nslookup does fail. But I did confirm that the esx hosts are pointed to the correct (only) DNS server I have in the lab environment.

[JLogan2016]

I also checked a traceroute from the esx host, and one hop to the DC. Same in the other direction from the DC

[daphnissov]

If nslookup fails from your DC, it's a DNS issue and has nothing to do with ESXi.

[JLogan2016]

I get that it is a DNS issue, just cannot fathom where. All Windows machines in the environment can resolve by hostname; it is only the ESXi hosts that cannot. And all machines in this lab have the same IP configuration.

[daphnissov]

It sounds like you need to start troubleshooting the resolution problems from your DC. Questions to ask and then answer would be:

1. Is any DNS resolution possible from the DC?
2. If yes, which records fail? If no, check DNS server, firewall, and protocol level interruptions,
3. If some resolution is possible, do the ones that fail have in common they were all added recently?
4. Are host file entries getting in the way?

[JLogan2016]

Regarding #1:

   As mentioned, all resolution is working except the esx hosts. All Windows machines can resolve fine. And the ESX hosts can resolve the Windows machines, just not the reverse.

   Resolution has to be working because the ESX host successfully joined the domain through the web console, although I had to access said console via the host's IP.

   Putty shows that I can resolve all Windows machines' names from the esx host. Windows just cannot resolve the reverse.

Regarding #4 - I have added no static host file entries, and see no entries in it aside from the 127.0.0.1 that I would expect.

I am going to rebuild the ESX hosts one at a time and see if I can figure out what may have gone wrong. I tear this lab down and rebuild often, so am pretty comfortable with the steps. Was just hoping someone had seen something like this before.

[bhards4]

Hi,

Please add the entry of host into resolve.conf and add the same into the windows machine into  C:\Windows\System32\drivers\etc\hosts by IP, FQDN, Shortname.

-Sachin