Enable SSH agent forwarding, and use your uploaded SSH key to log into one of the gateways:

GroupHost

STAR

Special interactive nodes only accessible to selected users: rcas6001-6004 

General purpose interactive: rcas6005-6016

PHENIX 

General purpose interactive: rcas2061-2068

SPHENIX 

General purpose interactive: sphnx01-08 

Development host: sphnxdev01 

Central job submission: phnxsub01-04

ATLAS T3 

General purpose interactive: spar0101-0108

EIC 

General purpose interactive: eic0101-0112

DUNE 

General purpose interactive: dune0001-0004

Astro 

General purpose interactive: astro0101-0104

Theory/BRAHMS/Misc 

General purpose interactive: rlnxsp01-02

General interactive

 (Belle II, NPPS, etc.) 

General purpose interactive: spool0001-0002

Example of ~/.ssh/config

Using ProxyJump through the gateway to the spar hosts:

Host spar*
    User your_username
    Hostname %h.usatlas.bnl.gov
    ProxyJump your_username@ssh.sdcc.bnl.gov