Detecting the use of BCC from the content filter

This is a simple content filter rule that will help you in filtering messages where the current destination was BCC’d rather then being listed in the TO or CC field.

Note that this will trip on most mailing lists — This is correct behaviour, unless the mailing list fills in the recipient’s name in the TO field (and most do not), lists are essentially using BCC.

It only works reliably in the LocalQ, it won’t work in the RemoteQ unless you turn off smartspooling, and it only works for mail received via SMTP, not MultiPOP or DomainPOP.

[Rule001]
RuleName=Detect BCC’d messages
Enable=No
ThisRuleCondition=All
ProcessQueue=LOCAL
Condition01=TO|does not contain|AND|$HEADER:X-Rcpt-To$|
Condition02=CC|does not contain|AND|$HEADER:X-Rcpt-To$|
Action01=add header|”X-BCC”,”True”

To use this rule, copy the above text and paste it into the very top or very bottom of your MDaemonAppcfrules.dat file using Notepad, then open the content filter dialog in MDaemon and enable the rule.

No semaphore files needed, no need to restart MDaemon.

MDaemon’s eventlog codes

MDaemon generates a number of entries in the Windows eventlogs to assist administrators in monitoring for specific important events. Below is a list of the various eventlog codes that MDaemon uses at this time:

Happy monitoring!

IMAP.MRK file format

I managed to dig up some information on the IMAP.MRK file, for anyone brave enough to want to modify it pragmatically. The format is actually fairly simple, one header followed by zero or more message records.

If a MSG file has no corresponding record, MDaemon will update the IMAP.MRK file the next time an IMAP client or WorldClient user touches the folder, and the message will be treated as UNSEEN and UNREAD

The header is defined as follows:

struct IMAPMrkHeader
{
unsigned HeaderVersion;
unsigned UIDValidity;
unsigned UIDNext;
unsigned LastWriteCounter;
unsigned Filler0;
unsigned Filler1;
unsigned Filler2;
unsigned Filler3;
unsigned CRLF;
};

Each MSG file will have one record, which is defined as follows:

struct IMAPMrkMessage {
char Filename[MAX_IMAP_FILENAME];
unsigned char Flags;
unsigned UID;
unsigned Size;
time_t Date;
};

#define FLAG_SEEN 32
#define FLAG_ANSWERED 16
#define FLAG_FLAGGED 8
#define FLAG_DELETED 4
#define FLAG_DRAFT 2
#define FLAG_RECENT 1
#define MAX_IMAP_FILENAME 23
#define IMAP_RECORD_SIZE 36

So what do all those fields mean?

• HeaderVersion is a tag to identify what file format the IMAP.MRK is using. The current value is 1. UIDValidity is the IMAP UID Validity for the folder. UIDNext is the UID that will be used for the next message added to the folder.
• LastWriteCounter is a value that changes whenever something has changed in the file. This was added when IDLE support was added to the IMAP server, so that there’s a quick way to check for changes (by comparing this one value rather than doing a compare of the entire file’s contents).When changing records in the file, lock the IMAP folder, increment the LastWriteCounter, change the records, then unlock the folder.
• UIDNext is the next UID to be assigned. To add records, lock the IMAP folder, increment the LastWriteCounter, and for each record you’re adding, use the current UIDNext value as its UID and then increment UIDNext.

So how do you lock a folder?

• Lock an IMAP folder by creating a file “IMAP-foldername-email.lck”, where foldername is a “filename-safe” version of the folder name (” and ‘/’ characters replaced with ‘_’) and email is the owner’s email address (use “public” for public folders). If the lock file already exists, something is currently operating on the IMAP.MRK so you should wait until it is unlocked before you lock it and continue.

Hope this helps someone.

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