[closewith]

usarmy (U.S. Army)

jble (Joint Base Langley-Eustis)

tradoc (Training and Doctrine Command)

mbx (mailbox)

eustis (Fort Eustis)

tboc (Training Brain Operations Center)

dtl (Data Transmission Lab)

helpdesk (help desk)

mail (mail)

mil (military domain)

Tells you everything you need to know.

[inanutshellus]

Note also the significance of the dots vs dashes in their taxonomy. Once it gets to "mailbox" it's all dashes, signifying no more breakdown by the overarching system beyond "we finally hit a mailbox designation".

I presume that dashed bit is what we'd think of as a normal email address.

[p_l]

looks like gateway address between SMTP and X.400