Version 6.11.0 of the LDM package has just been released.
The main new feature of this minor release is the addition of a
transitory database of information on local upstream LDM processes. The
database is transitory because it only exists while an LDM server is
running. The database is primarily used to determine whether or not an
incoming data-request duplicates or otherwise overlaps with an existing
data-request from the same downstream host. If it does, then the request
will be rejected.
The motivation for this new feature is to prevent an accidental or
deliberate denial-of-service (DOS) attack on an LDM server (believe it
or not, an accidental DOS attack did occur at the Unidata Program Center
-- causing some legitimate downstream sites to be denied data).
This release has a new utility, uldbutil(1), for listing the contents of
the database. The LDM user can use this utility to easily determine what
data they're getting from which upstream LDM-s. Naturally, this utility
has a manual-page.
No similar database exists for downstream LDM processes because there is
a one-to-one correspondence between such processes and the REQUEST
entries in the LDM configuration-file, etc/ldmd.conf. If you want to
know about locally-executing upstream LDM processes, then just grep(1)
the LDM configuration-file (e.g., "grep -i ^request $HOME/etc/ldmd.conf").
Version 6.11.0 can be downloaded at
This version's homepage is