0a6419d7__virus_filter_for_SMTP_servers__Comments
[Token] HELO [Type] Verb [Reference] RFC2821 [SMTP server] Required [Comments] 
Should be the first command is an SMTP conversation. Identifies sending SMTP server
ESMTP Keywords and Verbs (commands) Defined - Fluffy the SMTPGuardDog - spam and virus filter for SMTP servers
Comments