From 328db510329374eb66d43195c55fc9b37123dd9f Mon Sep 17 00:00:00 2001 From: Dario Ernst Date: Sat, 9 Feb 2019 12:33:33 +0100 Subject: [PATCH] Add FAQ about clients on port 25 generating non-helpful errors --- docs/faq.rst | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/docs/faq.rst b/docs/faq.rst index 4abd8874..cec7fb98 100644 --- a/docs/faq.rst +++ b/docs/faq.rst @@ -421,3 +421,7 @@ We **strongly** advice against downgrading the TLS version and ciphers! .. _`681`: https://github.com/Mailu/Mailu/pull/681 .. _`698`: https://github.com/Mailu/Mailu/issues/698 .. _`unbound`: https://nlnetlabs.nl/projects/unbound/about/ + +A user gets ``Sender address rejected: Access denied. Please check the message recipient […] and try again`` even though the sender is legitimate? +```````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````` +First, check if you are really sure the user is a legitimate sender, i.e. the registered user is authenticated successfully and own either the account or alias he/she is trying to send from. If you are really sure this is correct, then the user might try to errornously send via port 25 insteadof the designated SMTP client-ports. Port 25 is meant for server-to-server delivery, while users should use port 587 or 465.