Just noticed that since about a week ago the mail server stopped inspecting for spam. Mail flows to users but without the mailscanner functionality. Looking at mailwatch I do see that since a week ago it no longer registers new mail - either good or otherwise. Everything else looks normal. Mailscanner is running (see below). Restarting the mailscanner service does not present meaningful logs.
Please help.
No more spam filtering. Everything that's not filtered by postfix filters goes through. Mailwatch stopped showing new mail. I think it stopped working around the same time I 'yum update' some php related stuff.
Found the reason.
In the file header_check I remarked the hold line. I was not aware that this line is crucial to the whole mailscanner-related functionality.
Recommend adding a warning text in the file next to the above line not to modify/remark it.