VPS + Virtualmin + Google Apps: DNS

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#1 Mon, 05/09/2011 - 17:48
EZ

VPS + Virtualmin + Google Apps: DNS

Moving on to the next topic: DNS.

I'm not really a DNS expert, but as I see it there are 2 basic options:

  1. Manage DNS locally on the server. Advantage: ease of use (Virtualmin) and full control. Disadvantage: if the VPS goes down (with DNS) then mail service is unnecessarily interrupted.

  2. Use external DNS service, either provided by domain registrars, or seperate DNS provider (free/paid). Advantage: redundancy (assuming a good provider) ensures that even when the VPS is down, mail and other Google Apps services are unaffected. Disadvantage: not managed by Virtualmin, sometimes not very flxible.

Of course there are combinations and variations:

  • Master DNS on the VPS and external Secondary (backup) DNS, or vice versa. This is usually only possible with paid DNS services, as most registrars and free DNS services do not support master <-> secondary configurations (but there are exceptions, eg. http://xname.org).

  • Use another (cheap) VPS as DNS backup. This has the advantage of centralized management by Virtualmin (or Webmin?).

  • Use two external DNS services, set up as Master <-> Secondary.

  • For few domains, manually updating two DNS systems isn't too hard. Those may be local and external or both external.

So, if mail and maybe other services are offloaded to Google Apps, it's a good idea to have an external DNS service. But should we keep the local DNS as well? I think that the answer depends on two factors:

  1. How good is the external DNS? If the provider runs several servers on different networks around the world, then local DNS isn't really needed. Unless...

  2. ... web sites and scripts generate a lot of outbound traffic (eg. sending newsletters). In this case the local DNS server may improve the performace of such operations, enough to justify the RAM it uses. Alternatively, if the VPS host runs a DNS server on the same LAN, then it may obviate the need for a private (VPS local) DNS.

In case there is no need for a local DNS, the steps to disable it are:

  1. For every existing server and sub-server - Uncheck the following: Edit Virtual Server -> Enabled Features -> DNS domain enabled.

  2. Uncheck the following: Virtualmin -> System Settings -> Features and Plugins ->
    BIND DNS domain
    Slave DNS domain

  3. Select (check) and click Disable Now and On Boot the following: Webmin -> System -> Bootup and Shutdown -> bind9

Comments, corrections and additions please...

Eyal.

Mon, 05/09/2011 - 18:22
andreychek

That looks like a pretty good list of all the available options. Unfortunately, which one is best depends on your own needs -- so you'd have to weigh the benefits and drawbacks.

BIND can use a bit of RAM, so if you're goal is to minimize RAM use on your server, that may point to running DNS completely at a third party.

-Eric

Wed, 06/08/2011 - 01:18
pcspyoffice

Hello! EZ give me a great ideea , and a few days ago I decide to configure my domains in this kind of configuration! But I now I am in a dilema: I want to use virtualmin dns server for private lan and xname server as dns server for internet domain. In this situation what is the best solution: virtualmin server or xname dns server as master?

Fri, 06/17/2011 - 03:47
EZ

@pcspyoffice,

I don't lurk here on a daily basis so I've just now seen your questions.

As I mentioned above I'm not a DNS expert, but I'll try to help or at least suggest a basic idea that you'll have to explorer further, however I need some more informations.

First of all, Virtualmin is not a DNS server. Virtualmin can set up and manage the BIND name server. Also, Virtualmin is typically used to manage a web server, but you mention a private LAN.

Please provide some more information about your setup and goals. The following questions may guide you:

  1. Do you use Virtualmin to manage a server on your LAN, or on a hosted service?

  2. Why do you need DNS for your LAN? For looking up external hosts (eg. web sites) you can use your ISP's name servers.

  3. If you need a local DNS for looking up internal hosts, then how do you plan to update the name server with the names/addresses of the hosts?

  4. If the information is static and the LAN is small, why not simply create a hosts file and put it all on the clients?

  5. You may also use an external DNS (eg. BIND on your web server or xname.org). Unless the LAN is huge, DNS lookups to a remote name server should not cause any noticeable problem. How big is your LAN?

Regards,

Eyal.

Fri, 06/17/2011 - 04:11 (Reply to #4)
pcspyoffice

So

1.Do you use Virtualmin to manage a server on your LAN, or on a hosted service?

I use Virtualmin to hoste some internet domains, but I wonder If I can use virtualmin as DNS server for internal network (LAN). The server has only one network card with static ip (192.168.1.1) conected to gateway router with internet ip static : 89.xxx.xxx.xxx. The internal ip is configure on DMZ zone.

2.Why do you need DNS for your LAN? For looking up external hosts (eg. web sites) you can use your ISP's name servers.

I need DNS on LAN because I want to create some internal vhost form intranet aplications.

3.If you need a local DNS for looking up internal hosts, then how do you plan to update the name server with the names/addresses of the hosts?

Hmm ! This aspect of the problem I miss...

  1. If the information is static and the LAN is small, why not simply create a hosts file and put it all on the clients? On small LAN networkks( up to 10 workstation) I will do that.

What is the best choice for situation when ypu host internet domain on virtualmin? A lot of them...

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