Optimizing DNS settings

Often the latency that people see when they have a solid connection but things take a while to load (more specifically to begin to load) can be blamed on mis/poorly configured DNS.

I'd be very interested to hear advice from you experts regarding how best to configure DNS. I have a small home network that gets its broadband access from a long-range wireless signal. I recently put the OpenDNS addresses into my Buffalo router's DNS fields, but I still see what seems to me to be a fair amount of latency.

Is it better to put the DNS addresses in the Network panels of Sys. Prefs on each manchine, and leave 'em blank on the router?? Is there a way to test which configuration is best? What can a user do to make sure they're minimizing latency?

Inquiring minds want to know!

Thanks, John

One common solution to DNS woes on Macs is to disable IPv6 since it isn't widely supported yet.

System Preferences/Network pick built in Ethernet (or whatever your broadband is connected to) and TCP/IP. At bottom is button to configure IPv6.Make sure its set to off and save.

--Jim

>I had the same problem on my home internet satellite hookup. On
>satellite internet, there is a latency of about .5 sec. for every
>connection, and every DNS lookup. The overarching problem is due to
>a design flaw of http, if you will.

Or just a matter of physics, given that your next hop is extraterrestrial. =)


>The fix is to install a dns server on your client mac.

Indeed... they key is to have a DNS cache, or resolving server as
physically CLOSE to you as possible.

--chuck

________________________________________________________________________
traceroute is a disconcertingly blunt hammer; that we continue to use it
to essentially nail moving jello to a wall says more about us than about
anything on the Internet. --k claffy, At 8:43 -0700 10/17/02 on NANOG

At 7:08 AM -0800 2006/12/20, jiclark wrote:
> Often the latency that people see when they have a solid connection but
> things take a while to load (more specifically to begin to load) can be
> blamed on mis/poorly configured DNS.
>
>I'd be very interested to hear advice from you experts regarding how
>best to configure DNS. I have a small home network that gets its
>broadband access from a long-range wireless signal. I recently put
>the OpenDNS addresses into my Buffalo router's DNS fields, but I
>still see what seems to me to be a fair amount of latency.
>
>Is it better to put the DNS addresses in the Network panels of Sys.
>Prefs on each manchine, and leave 'em blank on the router?? Is there
>a way to test which configuration is best? What can a user do to
>make sure they're minimizing latency?
>
>Inquiring minds want to know!

        When you're looking up a name or IP, your Mac doesn't care
how it found the DNS server, so it's probably most convenient to have
your Buffalo provide the info. If you travel, and want to use OpenDNS
instead of whatever your local router provides, then you might want
to configure your laptops for OpenDNS directly.

        To find out which servers are fast vs. slow, use the 'host'
command. With -v, it tells you how long it took to get an answer. The
first time may be longer, if the DNS server you asked has to ask
another server for the answer; after that, it's in cache and faster.

        See if OpenDNS' servers are faster than your ISPs...


                                                Chris

pepperpepperbook:~$ host -v www.tidbits.com ns1.reppep.com
Trying "www.tidbits.com"
Using domain server:
Name: ns1.reppep.com
Address: 66.92.104.200#53
Aliases:

;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 43997
;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 4, ADDITIONAL: 0

;; QUESTION SECTION:
;www.tidbits.com. IN A

;; ANSWER SECTION:
www.tidbits.com. 511 IN CNAME tidbits.com.
tidbits.com. 511 IN A 216.168.61.78

;; AUTHORITY SECTION:
tidbits.com. 511 IN NS remote2.easydns.com.
tidbits.com. 511 IN NS ns1.easydns.com.
tidbits.com. 511 IN NS ns2.easydns.com.
tidbits.com. 511 IN NS remote1.easydns.com.

Received 151 bytes from 66.92.104.200#53 in 9 ms
--
Chris Pepper: <http://www.reppep.com/~pepper/>
                             <http://www.extrapepperoni.com/>
Rockefeller University: <http://www.rockefeller.edu/>

On 12/20/06 10:08 AM, "jiclark" <jiclarkindependence.net> wrote:

> I'd be very interested to hear advice from you experts regarding how best to
> configure DNS.

From David Pogue of the New York Times comes OpenDNS.com
(<http://www.opendns.com/>).

--
Shawn King
Host/Executive Producer
Your Mac Life
http://www.yourmaclife.com

jiclark said:

>What can a user do to make sure they're minimizing latency?


Have a look at:

<http://www.macosx.com/forums/howto-faqs/6323-howto-speed-up-dns-lookups-osx.html>

Randy B. Singer

Co-Author of:
The Macintosh Bible (4th, 5th and 6th editions)

OS X Routine Maintenance
http://www.macattorney.com/ts.html

On 3-Jan-2007, at 07:00, Randy B. Singer wrote:
> <http://www.macosx.com/forums/howto-faqs/6323-howto-speed-up-dns-
> lookups-osx.html>

That is seriously out of date.

Don't use this readme if you are running 10.3 or later, and possibly
not even 10.2

I have had horrible problems with Sprint/Embarq DNS servers. For a while, on some days I couldn't get the web to show up AT ALL. It was clearly a DNS problem. Upon talking with the tech support guy, I then put in alternative manual DNS numbers in the TCP/IP window. I did this on all my computers. It worked, but it is still slow on the lookups--but not on the speed of the network after the lookup. By slow, I mean that sometimes it might take 30-40 seconds OR MORE for the first lookup---even now.

The slowness of the connection jumped out at me the other day when I logged on with my son's Windows computer on the same network--the lookups were lightning fast.

So I can disable IPv6 or I can use openDNS? Should I use IPv6 if I use openDNS? But Wait! If I am using a Linksys router, wouldn't the router access the DNS? And then, wouldn't it be the same speed for both the Mac and the Windows?

(While I was typing this, I just opened another window--it took about 15-20 seconds to call up Google. HuH? And I've been online for an hour.)

I was ready to send a letterbomb to Sprint, but I guess I need to fix somthing--I just don't know what.

I've experienced similar issues. I have two networks in my home. One behind a Checkpoint Edge firewall and another behind a Linksys Router. My recently purchased Macbook, works fine behind the Edge box but can't resolve anything behind the Linksys. I've manually coded the vendor's DNS addresses into the setting but still no results behind the Linksys.

Quoting Clyde Kahrl <ckahrlclydekahrlesq.com>:

> So I can disable IPv6 or I can use openDNS? Should I use IPv6 if I
> use openDNS? But Wait! If I am using a Linksys router, wouldn't the
> router access the DNS? And then, wouldn't it be the same speed for
> both the Mac and the Windows?

Disable IPv6 first. Your linksys router, along with most of the
internet, doesn't support it (except China) so there is no point in
having it on.

If that doesn't pick up the speed, try configuring your Mac to use the
OpenDNS servers directly (there may be a problem with Linksys's DNS
that it doesn't like the Mac requests for some reason.)

On 6/01/2007, at 9:48 AM, kevinvanhaaren.net wrote:

> Disable IPv6 first. Your linksys router, along with most of the
> internet, doesn't support it (except China) so there is no point in
> having it on.
        
        Unless you run stuffit expander. There are known problems with
stuffit expander not running unless you have IPv6 turned on. What a
program like stuffit has to do with network protocols I don't know.

On 8-Jan-2007, at 12:05, Jason Campbell wrote:
> On 6/01/2007, at 9:48 AM, kevinvanhaaren.net wrote:
>> Disable IPv6 first. Your linksys router, along with most of the
>> internet, doesn't support it (except China) so there is no point in
>> having it on.
>
> Unless you run stuffit expander. There are known problems with
> stuffit expander not running unless you have IPv6 turned on. What a
> program like stuffit has to do with network protocols I don't know.

Funny Aside with the current Stuffit expander.

It opens and starts expanding the rare .sit archive I receive and
throws up a license dialog. I wait until the expansion is complete,
and then decline the license.

tee hee

Sorry, I had to share, it makes me happy every single time.

Randy Singer wrote:

Have a look at:

<http://www.macosx.com/forums/howto-faqs/6323-howto-speed-up-dns-lookups-osx.html>

Then, Lewis Butler said:

That is seriously out of date.

Don't use this readme if you are running 10.3 or later, and possibly not even 10.2

I've been wondering if Randy would chime back in about this. Before I discovered how old that post from OSX.com was, I went ahead and applied the relatively short first part of that 'readme', with no apparent ill effects.

Can anyone else chime in regarding this suggestion, especially in regards to the changes in the OS since then?

Thanks, John