= STARTTLS =

'''STARTTLS''', more officially called '''Opportunistic TLS''', is an extension to any unencrypted protocol that enables upgrading the connection to [[Encryption/TLS|TLS]].

<<TableOfContents>>

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== Usage ==

Following the establishment of a [[Protocols/TCP|TCP]] connection:

 * server sends `220 ready`
 * client sends `EHLO`
 * server sends `250 STARTTLS` (among other available commands)
 * client sends `STARTTLS`
 * server sends `220 GO HEAD`

Now a [[Encryption/TLS|TLS]] negotiation begins.



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CategoryRicottone