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[IDD #CSR-396593]: [Fwd: Re: NEXRAD Level II data]

Hi John,

> Does the IP number just need to be resolvable?  Can I have a public IP
> number that resides behind the firewall?

The ALLOW part of the LDM security is best employed for hosts that
have forward and reverse DNS.  The LDM supports ALLOWs by IP, but
relay nodes typically are hesitant about configuring their systems
for this.  In special cases, the upstream(s) can simply add an entry
in their /etc/hosts file that will define the correspondence between
machine IP and host name.  This would get around a lack of forward/reverse

> I can do it either way, but I think our IT folks would be more
> comfortable if I could use a resolvable IP number that was behind a
> firewall.

There is no problem being behind a firewall _IF_ the firewall is configured
to allow traffic on port 388.  Most sites machines sit behind firewalls
and are locked down for most traffic.

(if I initiate the communication to the upstream server, the
> port traffic will pass)

LDM transfers are initiated by the downstream (you in this case).  Your
LDM installation informs the upstream feed site(s) of which data you want
from one or more IDD datastreams and then the connection is turned around.
When the upstream(s) receive the data your machine has indicated that
is desired, it is immediately sent to your machine.  Since your LDM
is listening on the connection, there is no wait on your end.

Please let me know if this answered your questions.

> John M. Trostel
> Senior Research Scientist
> Georgia Institute of Technology
> Atlanta, GA 30332 USA


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Ticket Details
Ticket ID: CSR-396593
Department: Support IDD
Priority: Normal
Status: Closed