Re: Getting LDM on plane to receive via UCAR RAS and PPP

Janet,

>Date: Wed, 15 Jun 2005 10:13:11 -0600
>From: Janet Scannell <address@hidden>
>Organization: UCAR
>To: address@hidden
>Subject: LDM questions

The above message contained the following:

> I took your LDM class last November and I have some questions.  I am 
> trying to get the LDM to work between the aircraft and the ground.  I am 
> running LDM version 6.3.0 on a Fedora Core 3 machine (cirque) on the 
> aircraft which is the downstream LDM.  I am running LDM version 6.1.0 on 
> a Fedora Core 2 machine (linus) on the ground which is the upstream 
> LDM.  When the aircraft computer is attached to the internal network, 
> the LDM works correctly.  When I put files in the queue on linus, they 
> do appear on cirque.  When I connect cirque to RAS over a ppp link, I do 
> not get any files on cirque from linus when I insert new files into the 
> data queue on linus.  In the ldmadmin-pl.conf file, I did not put in a 
> specific ip address, so the LDM should listen on all networks.  Does the 
> LDM listen on ppp network links?

It's irrelevant what interface (i.e., IP address) the LDM on Cirque
listens because it's only receiving data: no other LDM-s connect to it.

The LDM on Linus will listen on all interfaces and doesn't really know 
or care that Cirque might be using PPP.

> What machine name do I put in the 
> ldmd.conf file on linus?  When I connect to RAS, cirque gets a name such 
> as ras34.ucar.edu (128.117.68.34).  This name can change every time I 
> make a connection to RAS.  Cirque also has the name cirque.p3.public.net 
> (192.168.10.105).  I did put both of these names in the ldmd.conf file 
> on linus, but cirque didn't get any new data from linus. 

The ALLOW entries for Cirque should cover all RAS names and also
Cirque's standard name.  For example:

    ALLOW       ANY     ^cirque\.p3\.public\.net$
    ALLOW       ANY     ^ras[0-9]*\.ucar\.edu$

There's actually a "public.net" domain?

> Another question:
> I can't get any information to show up in the log file on cirque.  Here 
> are the relevant parts of the /etc/syslog.conf file on cirque:

> # Log anything (except mail) of level info or higher.
> # Don't log private authentication messages!
> *.info;mail.none;news.none;authpriv.none;cron.none;local0.none  
> /var/log/messages
> # Save LDM messages to ldm log
> local0.debug                                            
> /jnet/local/ldm/logs/ldmd.log

The above entries aren't in the right format: there are newlines before
the destination fields.  They should look like this:

    # Log anything (except mail) of level info or higher.
    # Don't log private authentication messages!
    *.info;mail.none;news.none;authpriv.none;cron.none;local0.none      
/var/log/messages
    # Save LDM messages to ldm log
    local0.debug                                /jnet/local/ldm/logs/ldmd.log

I assume the breaks are due to your user-mail-agent.

Otherwise, the entries look good.  You might try, however, replacing
"local0.debug" with "local0.*" -- although it shouldn't make any
difference.  Also, ensure that the separators between the fields are tabs
and not spaces (although, again, it shouldn't matter).

In order for the "syslog.conf" entries to take effect, the system
logging daemon, syslogd(8), must be sent a SIGHUP.  In order for ldm
system to do that, the program "bin/hupsyslog" must be owned by "root"
and setuid.  Is it?

syslogd(8) also won't write to a non-existent file.  The file
"/jnet/local/ldm/logs/ldmd.log" should have been created by the
ldmadmin(1) script if it didn't exist.  Does it exist?

You can use the logger(1) utility to test the logging mechanism.  For
example:

    logger -p local0.notice "This is a test at level NOTICE"

> I get information in the log on linus and I compared the syslog.conf 
> files on both machines and they had the same information in them for the 
> ldm logging.  syslogd is running on cirque and cirque has been rebooted 
> after I changed the syslog.conf file and the log messages still don't 
> appear.  I tried the logger command that I found in 19990222 in the 
> mailing list archive on Unidata web site and that didn't work either.

Hmm...  Ensure that the logging file exists on Cirque and that the 
hupsyslog utility is owned by root and setuid and try the "shouldn't
matter" suggestions -- then get back to me.

> Thanks for your help,
> Janet
> x1093

Regards,
Steve Emmerson
LDM Developer