20030516: Brockport LDM server feed request changes (cont.)

>From: Tom McDermott <address@hidden>
>Organization: SUNY Brockport
>Keywords: 200305152244.h4FMi6Ld003975 LDM hostname feed request

Hi Tom,

>Could you do a reverse lookup on your name server right now for
>137.21.88.151 and tell me the hostname it returns.  Thanks.

Here is what I see on laraine.unidata.ucar.edu (128.117.140.62):

(laraine.unidata.ucar.edu) 1128 % nslookup 137.21.88.151
Server:         128.117.140.62
Address:        128.117.140.62#53

Non-authoritative answer:
151.88.21.137.in-addr.arpa      name = vortex.weather.brockport.edu.
151.88.21.137.in-addr.arpa      name = vortex.esc.brockport.edu.

Authoritative answers can be found from:
21.137.in-addr.arpa     nameserver = cadc.admc.brockport.edu.
21.137.in-addr.arpa     nameserver = dns2.admc.brockport.edu.
21.137.in-addr.arpa     nameserver = adrisc1.admc.brockport.edu.
21.137.in-addr.arpa     nameserver = ns.buffalo.edu.
cadc.admc.brockport.edu internet address = 137.21.80.109
dns2.admc.brockport.edu internet address = 137.21.1.16

(laraine.unidata.ucar.edu) 1129 % nslookup vortex.esc.brockport.edu
Server:         128.117.140.62
Address:        128.117.140.62#53

Non-authoritative answer:
Name:   vortex.esc.brockport.edu
Address: 137.21.88.151


By the way, in reviewing the correspondence that we exchanged it dawned
on me that one of my requests was for you to upgrade to LDM-6.0.11 even
though you are already running LDM-6.0.10.

This upgrade is not absolutely necessary since the change from 6.0.10
to 6.0.11 is very minor: a one line mod that changes the tenacity with
which a downstream LDM will keep trying to reconnect to an upstream
feed site that has apparently disappeared.  It was UQAM's feed of data
from vortex that showed that the requesting rpc.ldmd could be more
determined to reconnect to a site that disappears.

The change of who you request data from is, as you know, much simplier
and quicker than a new LDM installation.  What we had in mind was a
simple editing of ~ldm/etc/ldmd.conf to change all snow.nrcc.cornell.edu
requests to atm.geo.nsf.gov, and then a quick stop and restart of the
LDM:

% ldmadmin stop && ldmadmin start

I apologize for my not being clear enough about what was really desired.

Cheers,

Tom

>From address@hidden Fri May 16 16:18:45 2003

Tom,

I think the 'weather' entry is finally gone now:

935] vortex% nslookup - unidata.ucar.edu
Default Server:  laraine.unidata.ucar.edu
Address:  128.117.140.62

> set type=ptr
> 137.21.88.151
Server:  laraine.unidata.ucar.edu
Address:  128.117.140.62

Non-authoritative answer:
151.88.21.137.in-addr.arpa      name = vortex.esc.brockport.edu


On Fri, 16 May 2003, Unidata Support wrote:

> By the way, in reviewing the correspondence that we exchanged it dawned
> on me that one of my requests was for you to upgrade to LDM-6.0.11 even
> though you are already running LDM-6.0.10.

My compiler was broken; I've just got it running.

> This upgrade is not absolutely necessary since the change from 6.0.10
> to 6.0.11 is very minor: a one line mod that changes the tenacity with
> which a downstream LDM will keep trying to reconnect to an upstream
> feed site that has apparently disappeared.  It was UQAM's feed of data
> from vortex that showed that the requesting rpc.ldmd could be more
> determined to reconnect to a site that disappears.

I noticed that occasionally after a disconnect, the server would not
continue to try to reconnect to Cornell, usually with the HDS feed.  I was
going to contact support about this problem, but I've been too busy.  Now
I won't have to.  This is the only problem I've seen with ldm 6.

> The change of who you request data from is, as you know, much simplier
> and quicker than a new LDM installation.  What we had in mind was a
> simple editing of ~ldm/etc/ldmd.conf to change all snow.nrcc.cornell.edu
> requests to atm.geo.nsf.gov, and then a quick stop and restart of the
> LDM:
>
> % ldmadmin stop && ldmadmin start
>
> I apologize for my not being clear enough about what was really desired.

The problem was not in the change of the request, which is trivial, but
with the DNS problem.  Until that was resolved, I might not be able to get
any data elsewhere because connections would be refused.  This is the
problem I've had with Albany and Rutgers.  I hadn't had any problems with
Cornell, so I didn't want to change away until it was fixed.  Plus I've
had many more higher priority things to do.

Evidently our network people are managing their DNS database on an NT
machine, which makes it difficult, if not impossible, to do anything
remotely resembling intelligent.  So they inadvertently created a PTR
record from 137.21.88.151 to vortex.weather.brockport.edu, rather than a
CNAME from vortex.weather.brockport.edu to vortex.esc.brockport.edu, as I
had specified.  But strangely enough it took 2 years for this to finally
surface and bite me.

Tom
-----------------------------------------------------------------------------
Tom McDermott                           Email: address@hidden
Systems Administrator                   Phone: (585) 395-5718
Earth Sciences Dept.                    Fax: (585) 395-2416
SUNY College at Brockport