README: clarify that direct TLS for SMTP is not supported, STARTTLS is. #650
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The current implementation of the stash-box email package uses the
smtp.SendMail function which is part of the go standard library. But
this function only supports plain tcp connections and upgrades them
through STARTTLS. net/smtp has no function that can establish a TLS/TCP
connection (aka SMTPS).
When stash-box is configured to use a TLS port for email, it initiates a
plain tcp connection waiting for the SMTP server to start an SMTP
handshake. But the SMTP(S) server is expecting a TLS handshake so
stash-box hangs indefinitely until the TCP connection times out at which
point it returns "EOF". This is confusing and time-consuming for
administrators to investigate. Hopefully, this README clarification can
help avoid this confusion in the future.
Ultimately, if someone wants to put in the effort to properly implement
SMTPS support, it can be done with a higher-level package such as
emersion/go-smtp.
https://pkg.go.dev/github.com/emersion/go-smtp#DialTLS
Maista6969
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to Maista6969/stash-box
that referenced
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Jun 24, 2023
…s. (stashapp#650) The current implementation of the stash-box email package uses the smtp.SendMail function which is part of the go standard library. But this function only supports plain tcp connections and upgrades them through STARTTLS. net/smtp has no function that can establish a TLS/TCP connection (aka SMTPS). When stash-box is configured to use a TLS port for email, it initiates a plain tcp connection waiting for the SMTP server to start an SMTP handshake. But the SMTP(S) server is expecting a TLS handshake so stash-box hangs indefinitely until the TCP connection times out at which point it returns "EOF". This is confusing and time-consuming for administrators to investigate. Hopefully, this README clarification can help avoid this confusion in the future. Ultimately, if someone wants to put in the effort to properly implement SMTPS support, it can be done with a higher-level package such as emersion/go-smtp. https://pkg.go.dev/github.com/emersion/go-smtp#DialTLS
feederbox826
pushed a commit
to feederbox826/stash-box
that referenced
this pull request
Nov 15, 2023
…s. (stashapp#650) The current implementation of the stash-box email package uses the smtp.SendMail function which is part of the go standard library. But this function only supports plain tcp connections and upgrades them through STARTTLS. net/smtp has no function that can establish a TLS/TCP connection (aka SMTPS). When stash-box is configured to use a TLS port for email, it initiates a plain tcp connection waiting for the SMTP server to start an SMTP handshake. But the SMTP(S) server is expecting a TLS handshake so stash-box hangs indefinitely until the TCP connection times out at which point it returns "EOF". This is confusing and time-consuming for administrators to investigate. Hopefully, this README clarification can help avoid this confusion in the future. Ultimately, if someone wants to put in the effort to properly implement SMTPS support, it can be done with a higher-level package such as emersion/go-smtp. https://pkg.go.dev/github.com/emersion/go-smtp#DialTLS
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The current implementation of the stash-box email package uses the smtp.SendMail function which is part of the go standard library. But this function only supports plain tcp connections and upgrades them through STARTTLS. net/smtp has no function that can establish a TLS/TCP connection (aka SMTPS).
When stash-box is configured to use a TLS port for email, it initiates a plain tcp connection waiting for the SMTP server to start an SMTP handshake. But the SMTP(S) server is expecting a TLS handshake so stash-box hangs indefinitely until the TCP connection times out at which point it returns "EOF". This is confusing and time-consuming for administrators to investigate. Hopefully, this README clarification can help avoid this confusion in the future.
Ultimately, if someone wants to put in the effort to properly implement SMTPS support, it can be done with a higher-level package such as emersion/go-smtp.
https://pkg.go.dev/github.com/emersion/go-smtp#DialTLS