On 16/03/18 16:15, Anthony DeRobertis wrote: > Dovecot (IMAP) is working fine here with K-9. > > Since you're seeing different results in different clients, the most > obvious reason would be a different behavior from the two different ways > to connect to IMAP (or POP3) with TLS: > > * connect to port 993, start TLS negotiation > * connect to port 143, run STARTTLS command, start TLS negotiation
Both are 143/STARTTLS. > You can debug both with OpenSSL's s_client: > > openssl s_client -starttls imap -connect MAIL.YOURDOMAIN.COM:imap > openssl s_client -connect MAIL.YOURDOMAIN.COM:imaps Thanks, will have a play with that. Unfortunately, it seems to be intermittent (and relatively rare). Maybe it's just coincidence that Thunderbird never sees it ... > If you're seeing this on sending mail, that's SMTP — and there are > /three/ SMTP ports you might be using: 25, 465, and 587. 25 and 587 need > STARTTLS. s_client can deal with those, too. Haven't seen it with SMTP, but then I don't often send from K9. Typing is so much easier on a proper computer :-) > Once you've figured out what's happening, then you can determine if it's > something weird on your server or your VPS providers' network. Thanks :-) Richard
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