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Re: DNS load research

2005-03-19 13:39:28
Mark wrote:
Thank you for your comprehensive data. :) That pretty much settles it for
me (my mood, that is; the matter was already settled a long time ago).


    It results that 94.51% of the examined domains publish
    records which require 10 queries or fewer to resolve
    completely.


Wayne said he had ran the numbers, back when. And I trusted his math. For
good reason, it now seems.

My numbers show the cumulative query counts for the domains.

Anyway,

After doing this, I found some older log files that I hadn't used initially, and if I take them into account the stats change as follows:

The new top offenders:

jayde.com            |     03-101    | 00-33 | 00-00 | 01-34 | 01-33 |
jaydemail.com        |     02-101    | 00-33 | 00-00 | 00-33 | 01-34 |
absolutemotion.com   |     02-16     | 00-02 | 00-01 | 01-09 | 00-03 |
mail.classmates.com  |     03-14     | 00-01 | 00-02 | 01-08 | 01-02 |
microsoft.com        |     03-12     | 00-01 | 00-00 | 01-08 | 01-02 |
v2.listbox.com       |     04-12     | 01-02 | 00-01 | 01-06 | 01-02 |
about.com            |     01-11     | 00-00 | 00-00 | 00-09 | 00-01 |
sourceforge.net      |     03-11     | 00-00 | 00-00 | 01-09 | 01-01 |
sherban.com          |     02-10     | 00-01 | 00-02 | 01-04 | 00-02 |
citizensbank.com     |     03-10     | 00-00 | 00-00 | 01-04 | 01-05 |

The distribution:

    Queries Number of domains   Percentage of total
    1             148                55.43%
    2             11                 4.12%
    3             51                 19.10%
    4             22                 8.24%
    5             13                 4.87%
    6             8                  3.00%
    7             3                  1.12%
    8             1                  0.37%
    9             2                  0.75%
    10            2                  0.75%
    11            2                  0.75%
    12            2                  0.75%
    14            1                  0.37%
    16            1                  0.37%


    In total, I looked at 267 domains.

    It results that 97.0% of the examined domains publish
    records which require 10 queries or fewer to resolve
    completely.

    3.0% of the domains have SPF records more expensive than 10
    queries. I then looked at all these in detail to see why they
    need such expensive records and what could be done.

    The list now includes some new players, that are worth looking at:


microsoft.com (currently 12 queries)

   "v=spf1 mx redirect=_spf.microsoft.com"

   _spf.microsoft.com lists:

   "v=spf1 ip4:213.199.128.139 ip4:213.199.128.145
   ip4:207.46.50.72 ip4:207.46.50.82 ip4:131.107.3.116
   ip4:131.107.3.117 ip4:131.107.3.100 ip4:131.107.3.108
   a:delivery.pens.microsoft.com a:mh.microsoft.m0.net
   mx:microsoft.com ?all"

    [root(_at_)sun src]# host -t mx microsoft.com
    microsoft.com mail is handled by 10 mailc.microsoft.com.
    microsoft.com mail is handled by 10 maila.microsoft.com.
    microsoft.com mail is handled by 10 mailb.microsoft.com.


Verdict: Could reduce SPF record to *2 queries*

sourceforge.net (curently 11 queries):

    "v=spf1 mx a:mail.marblehorse.org a:sshgate.sourceforge.net
    a:mx-outbound.sourceforge.net
    a:lists-outbound.sourceforge.net
    a:sc8-sshgate.sourceforge.net a:smtp.vasoftware.com
    a:newcastle.devrandom.net -all"

Verdict: Could reduce to *4 queries*

sherban.net (currently 10 queries)

   "v=spf1 a mx ptr ip4:216.239.64.0/19 include:vif.net ?all"

   vif.net: "v=spf1 mx ptr ip4:216.239.64.0/19 ?all"

Verdict: Could reduce to *4 queries*

Regards,
Radu.


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