My server is sending spam. This snippet postcat shows for a mail in mailq: Code: regular_text: Date: Mon, 14 Sep 2020 03:53:24 -0700 regular_text: From: Lucian Dumitrescu <[email protected]> regular_text: To: undisclosed-recipients:; regular_text: Subject: Inquiry_Autoitalia 567892 regular_text: Message-ID: <[email protected]> regular_text: X-Sender: [email protected] regular_text: User-Agent: Roundcube Webmail/1.2.3 pointer_record: 1118311 regular_text: X-Spam: Yes Is it Roundcube that sends the e-mail? It does not say which account is sender, if that is the case. Or is it the website that is cracked to send spam? I have not managed to force the user to update that Wordpress site, so am considering shutting it down until it is updated. Another thing: how come my e-mail server sends e-mail where the sender domain is not on my server? pflogsumm shows in "Senders by message count" 12 messages by [email protected] Can I make RSPAM or someting to block sending messages like those? ISPConfig 3.1.15p3 on Debian GNU/Linux 9.13 (stretch).