I use a free DNS benchmarking piece of software to actually test my DNS 
fallback servers.  Out of the box, this tool
can measure the raw performance of a whole variety of publicly available 
DNS servers as they perform ON YOUR NETWORK.
This means that if you have a slow route to OpenDNS, but a fast one to 
google for network topology reasons, this tool
will show that.

It is really worth a look for anyone wanting to speed up their DNS 
performance.  If you run your own DNS server
with forwarding, make sure you compare the *non-cached* performance 
parameters (your local DNS should win hands down
for any cached requests)

On a LUG, it is probably bad form to recommend a MS windows utility, but 
flame away, this tool performs a useful task:

http://www.grc.com/dns/benchmark.htm

-- Kevin

Ubuntu Server 10.04


On 1/13/2011 10:44 AM, Mr. B-o-B wrote:
> Hello, and a good day to you all.  I was wondering if anyone has ever used
> the public Goggle DNS servers, and if they are reliable.
>
> I recently installed a WAN traffic manager at two of our locations.
>
> http://www.ecessa.com/pages/products/products_powerlink_pl200.php
>
> These units are cool.  I am now bonding 3 isp data connections at one
> location, and two isp connections at the other.  It also allows me to do
> line bonding for site to site vpn connections which was a selling point
> for me (why is the system slow calls from the remote office have
> seriously decreased :) ).
>
> Since I installed this unit, I have notice a slight performance hit in the
> DNS department.  Internally I have a Slackware box running BIND as a
> caching nameserver.  Beneath that there are a
> handful of M$ (sorry guys,
> but it's a business&  corporate is clueless) AD - DNS servers that
> maintain&  handle the local dns
> &  forward external requests to the Slackware BIND box.  Prior to
> installing the traffic manager, I had BIND setup to forward its
> unknown non-cached requests
> to the ISP DNS servers that was hooked up to my LAN.  This worked great
> for years.  When I hooked up the traffic manager, I added the other ISP
> dns servers to the list of forwarders in my BIND config.  After all,
> half the reason I picked up the traffic manager was for redundancy (in
> case ISP link 1 goes down, etc.).  Once I added the other ISP forwarder I
> started to notice delays in DNS queries.  Since the traffic manager is
> spitting out my traffic on 3 different ISP I believe this is where the
> problem is.  If my BIND sends a forward query to ISP DNS 1, but the query
> is actually sent via ISP data link 2, or 3 then when DNS server 1
> receives the request it is saying "I don't think so stranger".  Then my
> BIND retries until it actually get the magic ISP DNS on the correct ISP
> link.  End result = Ring, Ring, Why does my browser take so long to
> load!.
>
> I realize I could just ditch forwarding all together, but I prefer to let
> an upstream ISP server handle the load&  not constantly bother the top
> level servers for every new request we get.  A solution I think would be
> to forward my dns queries to a server that will accept from any of our ISP
> lines.  I don't think I really trust the old 4.2.2.2, but I noticed Goggle
> has a public dns service @ 8.8.8.8.  This could solve my problems.
>
> Does anyone have an opinion on using the Goggle DNS?
>
> I have also considered putting a box on the outside of the traffic manager
> with 3 nics (one hooked into each ISP)&  running BIND that way.  Although I
> fell this would work fine, it just seems like more work that I want to do
> &  yet another thing I will have to worry about.
>
> Another option is the wan manager has QoS I can setup so all my
> external DNS
> forward requests go via one of the links.  I am reluctant to go this route,
> and I want to keep things as redundant as possible.
>
> Sorry for the long winded post.
>
> Thanks!
>
> B-o-B
>
>
>
>
>
> _______________________________________________
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> tclug-list at mn-linux.org
> http://mailman.mn-linux.org/mailman/listinfo/tclug-list

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