0a6419d7__virus_filter_for_SMTP_servers__Comments
[Token] NOOP [Type] Verb [Reference] RFC2821 [SMTP server] Required [Comments] 
NO OPeration. Does nothing but keeps the connection active and can help synchronise commands and responses.
ESMTP Keywords and Verbs (commands) Defined - Fluffy the SMTPGuardDog - spam and virus filter for SMTP servers
Comments