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DNS errors when performing http test

4 messages in this thread

list David Gilmore · Mon, 23 Jan 2006 14:52:42 -0500 ·
I keep getting DNS errors when performing the HTTP test against two W2k3
servers.  They are sporadic, and they recover almost immediately.  I am
using http://host.domain.local for internal DNS structure.  Is this the
problem?  No other HTTP test are failing, such as checking company website.
 
David Gilmore
Consultant
Stenhouse Consulting, LLC.
X Traverse St
Providence, RI   XXXXX
XXX.XXX.XXXX
XXX.XXX.XXXX (fax)
list Henrik Størner · Mon, 23 Jan 2006 22:02:45 +0100 ·
quoted from David Gilmore
On Mon, Jan 23, 2006 at 02:52:42PM -0500, David Gilmore wrote:
I keep getting DNS errors when performing the HTTP test against two W2k3
servers.  They are sporadic, and they recover almost immediately.  I am
using http://host.domain.local for internal DNS structure.  Is this the
problem?  No other HTTP test are failing, such as checking company website.
DNS failures mean just that - the DNS lookup for "host.domain.local"
failed. 

Note that Hobbit will perform a DNS lookup of the hostname in the URL, 
regardless of what host this status is reported for. E.g. 

   10.0.0.1   myserver.foo.com  # http://www.foo.com/

will do a DNS lookup of "www.foo.com" to get the IP-address for the 
http tests. The "testip" flag has no effect on http tests; if you
want to force an http test to use a specific IP-address (and hence
avoid the DNS lookup), you can do it like this:

   10.0.0.1   myserver.foo.com  # http://www.foo.com=192.168.1.7/

This will make the http tests use the 192.168.1.7 address.


Regards,
Henrik
list Jeff Newman · Mon, 23 Jan 2006 15:48:32 -0600 ·
Kind of on the same topic, I noticed in my bbtest column:

DNS statistics:
# hostnames resolved  :       78
# succesful           :       76
# failed              :        2

Is there a logfile I can look at to see which 2 failed DNS lookups?

-Jeff
quoted from Henrik Størner


On 1/23/06, Henrik Stoerner <user-ce4a2c883f75@xymon.invalid> wrote:
On Mon, Jan 23, 2006 at 02:52:42PM -0500, David Gilmore wrote:
I keep getting DNS errors when performing the HTTP test against two W2k3
servers.  They are sporadic, and they recover almost immediately.  I am
using http://host.domain.local for internal DNS structure.  Is this the
problem?  No other HTTP test are failing, such as checking company
website.
DNS failures mean just that - the DNS lookup for "host.domain.local"
failed.

Note that Hobbit will perform a DNS lookup of the hostname in the URL,
regardless of what host this status is reported for. E.g.

  10.0.0.1   myserver.foo.com  # http://www.foo.com/

will do a DNS lookup of "www.foo.com" to get the IP-address for the
http tests. The "testip" flag has no effect on http tests; if you
want to force an http test to use a specific IP-address (and hence
avoid the DNS lookup), you can do it like this:

  10.0.0.1   myserver.foo.com  # http://www.foo.com=192.168.1.7/

This will make the http tests use the 192.168.1.7 address.


Regards,
Henrik

list Henrik Størner · Mon, 23 Jan 2006 23:19:41 +0100 ·
quoted from Jeff Newman
On Mon, Jan 23, 2006 at 03:48:32PM -0600, Jeff Newman wrote:
Kind of on the same topic, I noticed in my bbtest column:

DNS statistics:
# hostnames resolved  :       78
# succesful           :       76
# failed              :        2

Is there a logfile I can look at to see which 2 failed DNS lookups?
It doesn't get logged anywhere. You *can* run bbtest-net with the
--debug option, and it will spit out a line with
    DNS lookup failed for HOSTNAME ...
for those hosts that fail - among a lot of other debugging output.


Henrik