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[LDM #CSZ-262645]: errant LDM REQUESTs on sirocco.srcc.lsu.edu

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  • Subject: [LDM #CSZ-262645]: errant LDM REQUESTs on sirocco.srcc.lsu.edu
  • Date: Mon, 18 Feb 2013 08:35:28 -0700
Hi David, et. al.,

This is a quick update in advance of our conference call tomorrow at
13:00 MST:

Steve Emmerson, Mike Schmidt and I took a close look at LDM log
file entries on sirocco last Friday while after turning a feed
REQUEST back on to one of the real server backends of the 
idd.unidata.ucar.edu cluster.  We observed that ** something **
is inserting a reset message into the IDD stream to sirocco.
The reset message is causing the downstream process on sirocco
to believe that the connection has been closed, and sirocco
responds by opening a new connection.  The insertion of the
reset message is reminiscent of COMCAST's interference with
peer-to-peer service connections on its network.

In order to more fully investigate the reset messages being
added to the stream, we ran a series of tests using different
ports for the connection -- the LDM uses the well-known port
388 by default, but it can be built to use any port that
the user wants (but machines participating in the IDD all use
port 388).  The port being used on the upstream had no effect
on the observation that reset messages are being inserted into
the stream (we tried port 80, 8080, and 22).

Our hypothesis at this point is that some entity "close" to
LSU is purposely interfering with connections between LDMs
inside of the LSU or LSU/SRCC network and outside of the
LSU campus.  'traceroute's from machines external to LSU
suggest that this may be loni.org or net.internet2.edu.  My
guess (not necessarily shared by others here in the UPC) is
that the place to look is loni.org.

Cheers,

Tom
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Ticket Details
===================
Ticket ID: CSZ-262645
Department: Support LDM
Priority: Normal
Status: Closed