DNS Resolver & Manual Reverse Entries



  • I'm trying to setup a new home lab and apparently vCenter 6.0 REQUIRES reverse DNS otherwise the install fails.  Can someone tell me how to setup an entry in the host overrides or advanced section for a reverse lookup?


  • LAYER 8 Global Moderator

    they are created by default for anything you put in host over rides that is for sure

    C:>dig -x 192.168.9.100

    ; <<>> DiG 9.10.2-P2 <<>> -x 192.168.9.100
    ;; global options: +cmd
    ;; Got answer:
    ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 912
    ;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1

    ;; OPT PSEUDOSECTION:
    ; EDNS: version: 0, flags:; udp: 4096
    ;; QUESTION SECTION:
    ;100.9.168.192.in-addr.arpa.    IN      PTR

    ;; ANSWER SECTION:
    100.9.168.192.in-addr.arpa. 3600 IN    PTR    i5-w7.local.lan.

    ;; Query time: 1 msec
    ;; SERVER: 192.168.9.253#53(192.168.9.253)
    ;; WHEN: Sat Jul 18 06:18:05 Central Daylight Time 2015
    ;; MSG SIZE  rcvd: 84

    On a side note I find it really hard to believe that the install of vcenter requires PTR..  What error do you get?



  • I'll check again when I get home but I'm pretty sure it didn't work.

    I don't remember the exact message, but it was vague and said something about not being able to setup the network and then every step after that failed.  From some quick Googling it seems that this is new in 6.0.


  • LAYER 8 Global Moderator

    And what are you googling for - I don't see any such requirement.. Maybe my googlefu is off today?

    Why would it require PTR?  Its quite possible your having dns related problems or network issues, etc.. but for what reason would it need to look validate anything with PTR??

    Are you having problems with SSO ?  Do you have a AD domain?  I do see mention of PTR when setting up SSO, etc.  My lab box currently doesn't have the umph to install vcenter, nor do I really have a need for it, etc.  I just use the vclient to admin my esxi 6 box.



  • I bounced the DNS service and reverse started working.  I'll try the vCenter install again in the morning.

    Here's the official guide that says you need working host, FQDN, and reverse resolution (page 5, under "General Requirements").  There's also a bunch of random blog posts stating the same for the error message I received.

    https://www.vmware.com/files/pdf/techpaper/vmware-vcenter-server6-deployment-guide.pdf

    At the moment this is a completely clean environment.  Nothing but 3 vSphere 6.0 hosts and a pfSense box.



  • Ok, the issue seems to be that the DNS Resolver is responding REFUSED to any queries from networks not directly attached to pfSense.  I've got a L3 switch handling my internal routing and a single LAN connection for pfSense.  The vCenter VM is on a different network (10.21.96.0/24 instead of 192.168.218.0/24).

    I suppose this is a good find for me since this also would have screwed me over pretty well at work where I have a similar setup.  I just added the other locals to the Access Lists tab and am about to try another install…

    EDIT:  Finally got it working.  I've never had this much trouble installing vCenter before, though I've also never tried installing the appliance before either.  Between the resolver not spitting out any reverse dns, forgetting to add access control, and then stumbling around through a dozen installs which failed due to a bug in the installer (don't try to use NTP, which is the default), this has been a giant waste of time.

    Thanks for the help though.  Sometimes it just helps to have a sounding board.


  • LAYER 8 Global Moderator

    like to know why PTR or even forward is required for vcenter to be honest.. Seems like a useless requirement to me..  Glad you got it working though.


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