NCBI blocks any connection from computing nodes because they are behind firewalls. Thus OSC users cannot use SRA tools to download data "on-the-fly" at runtime on computing nodes, e.g. 'fastq-dump -X 5 SRR390728'. OSC users must download SRA data on login using the command 'prefetch' before any sequence analysis. Please see the section 'Download SRA Data' in the SRA Toolkit software page for more detail.