IGS GNSS products (i.e., orbits, station positions, EOP, clock solutions)
will no longer be mirrored at the ftp.igs.org.  Please see CDDIS or
one of the other Global Data Centers http://www.igs.org/about/data-centers
listed below for the IGS products.  CDDIS has a nice description of the
product layout here

https://cddis.nasa.gov/Data_and_Derived_Products/GNSS/orbit_products.html


IGS products will now only be available in subdirectories by GPS week at
the following locations:

CDDIS:  
https://cddis.nasa.gov/archive/gnss/products/


IGN:    
ftp://igs.ensg.ign.fr/pub/igs/products/


SIO:    
ftp://garner.ucsd.edu/pub/products/