topic Re: DNS Client in Operating System - OpenVMS

DNS Client

Brian_Pearson — Tue, 05 Jan 2016 10:43:33 GMT

Hi, I'm a windows engineer and being told by my VMS admin that he needs to have a copy of the DNS zone transferred to the VMS box as VMS can not resolve just by using a dns client pointing to a DNS server. Is this true or can VMS resolve by using a DNS client pointed to windows DNS servers?

Re: DNS Client

Steven Schweda — Tue, 05 Jan 2016 14:28:21 GMT

> [...] Is this true [...]

   I doubt it.

   It would be nice to get some basic info on the VMS system, like, say,
output from:
      tcpip show version
but, generally speaking, it sounds as if someone is confused. VMS has
its shortcomings, and I'm not an expert on all the different IP software
options which are available, but I've never heard of one, no matter how
old and lame, which lacks a working DNS resolver. And that includes a
client-only DNS resolver configuration.

   The obvious explanation would be inebriation, but it might be best to
get a detailed justification for the claim before jumping to that
conclusion.

Re: DNS Client

Hoff — Tue, 05 Jan 2016 17:58:24 GMT

OpenVMS contains a DNS resolver and a DNS server. Both work.

The resolver gets the translation from a DNS server. The DNS server can be local on the server, or can be remote.

You might want to point your OpenVMS administrator over here to the discussion, as there may well be some other details, or factors or requirements here that might make a local DNS server or the VMS analog of the hosts file necessary, such as a requirement for the server to operate without an external network dependency.

But in general, no, there's usually no reason to run a DNS server on OpenVMS. Particularly if there's another existing DNS server infrastructure already available.

Which means that most folks using OpenVMS run the DNS resolver only, and — for various reasons — not the DNS server. I'm aware of a number of OpenVMS servers that get their DNS translations from Windows Server DNS servers, as well as from DNS servers running on Linux and OS X Server configurations.

Some sites do use the integrated DNS server, of course. When last I checked, the integrated DNS server is a down-revision version of ISC BIND — BIND 9.3.1 (Nov 8 2014) — and which was desupported a while ago. ISC support for the 9.3 bits ended circa 2009. Which means there can be security and stability issues with it, particularly if the server is publicly exposed.

If there is need to run a DNS server, it'd be more common to run it as a secondary server, rather than with a manual transfer of a zone file and configuring as a primary. That configuration is entirely possible with BIND 9 servers, though I've not tried setting up ISC BIND 9 as a secondary of a Windows Server DNS server configuration.