On one server, I have a lot of mails bouncing when sent to specific providers (like Yahoo for instance). All the domains concerned have just a website hosted on this server. The DNS and mail server are handled elsewhere, so they don't have "DNS domain" or "Mail for domain" enabled.
The emails sent directly from the external mail server are fine. Only some mails sent from the website (via PHP mail function) are bouncing.
When I look in the mail log, I see 4 different type of errors for those bounced mails (the message seems to depend to which provider they are sent) :
Domain of sender address dgcogito@localdomain does not exist (in reply to RCPT TO command))
501 #5.1.3 Partial domain not allowed: 'localdomain' (in reply to MAIL FROM command))
501 Syntax error in parameters or arguments (in reply to MAIL FROM command))
552 sorry, your envelope sender domain must exist (#5.7.1)
I guess something must not be configured right on my server, but I have no idea where to look. Hope you can help.