I
illumination
Between the top 3 services offered "Gmail,Yahoo,Hotmail" i am only aware of Gmail utilizing and taking advantage of STARTTLS if it is offered and encrypts the SMTP transaction when a gmail user is sending mail.
Simple Mail Transfer Protocol session's between two mail servers may be encrypted, but only if both ends support it and or both ends choose to use it. The main reason, you could not trust email to be even moderately secure at the transport layer.
Simple Mail Transfer Protocol session's between two mail servers may be encrypted, but only if both ends support it and or both ends choose to use it. The main reason, you could not trust email to be even moderately secure at the transport layer.