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

Janet,

>Date: Fri, 17 Jun 2005 13:20:17 -0600
>From: Janet Scannell <address@hidden>
>Organization: UCAR/EOL/ATD
>To: Steve Emmerson <address@hidden>
>Subject: Re: Getting LDM on plane to receive via UCAR RAS and PPP

The above message contained the following:

> Actually, cirque.p3.public.net is a private ip address, so it is not in 
> dns anywhere.  cirque uses nat and ip masquerading  to get data  to and 
> from the  ground during flight.  Now, I have a ppp link on the plane 
> that is working  and  I can ping linus.atd.ucar.edu which is my upstream 
> ldm from cirque.  When I try using ldmping to linus.atd.ucar.edu, it 
> either gives a portmapper error or says that gethostbyname timed out.  

This means that the ldmping(1) on Cirque never reached Linus.  Because a
ping(1) of Linus from Cirque worked, we suspect that a firewall between
Cirque and Linus isn't allowing traffic on port 388 to pass through.

You can test this hypothesis by executing the command

    rpcinfo -t linus.atd.ucar.edu 300029 6

on Cirque (you might have to adjust the arguments: the "-t" means "TCP").
I suspect that it won't be able to connect.

We've encountered firewall problems like this numerous times.

> Therefore the ldm feed is not working to cirque and I was wondering if 
> you have any ideas that would help me out.  I have made the standard 
> entries in the /etc/services and /etc/rpc files and I did have the ldm 
> working when cirque was attached to the local network with a different 
> ip address.
> 
> Thank you,
> Janet

Regards,
Steve Emmerson