.TH RATFS 4
.SH NAME
ratfs  \- mail address ratification file system
.SH SYNOPSIS
.B ratfs
[
.B -d
] [
.B -c
.I configuration
] [
.B -f
.I classification
] [
.B -m
.I mountpoint
]
.SH DESCRIPTION
.I Ratfs
starts a process that mounts itself (see
.IR bind (2))
on
.I mountpoint
(default
.BR /mail/ratify ).
.I Ratfs
is a persistent representation of the local network
configuration and spam blocking list.  Without it
each instance of
.IR smtpd (6)
would need to reread and parse a multimegabyte list
of addresses and accounts.
.PP
.I Ratfs
serves a control file,
.BR ctl ,
and several top level directories:
.BR trusted ,
.BR deny ,
.BR dial ,
.BR block ,
.BR delay ,
and
.BR allow .
.PP
The control file is write only and accepts three
possible commands:
.TF "debug file
.TP
.B reload
rereads
.I classification
and
.I configuration
.TP
.B debug \fIfile\fP
creates
.I file
and sends debugging output to it.
.TP
.B nodebug
closes the debug file and turns off debugging
.PD
.PP
The directory
.B trusted
serves a file for each IP range from which all mail
is trusted.  The names of the files are CIDR blocks;
an IP address or an IP address followed by
.BR #\fIn\fP ,
where
.I n
is the number of bits to match.
To check if any IP address falls in a trusted
range, it is sufficient to open the file whose
name is the IP address.
For example, if
.B trusted
contains only the file
.BR 135.104.0.0#16 ,
an attempt to open the file 135.104.9.1 will
succeed while opening 10.1.1.1 will fail.
To determine the particular range matched,
.B dirfstat
(see stat (2))
the open file and the
.B name
field will be the matching CIDR range.
.PP
The trusted ranges come both from the
.B ournet
entries in the file
.I configuration
(default
.BR /mail/lib/blocked )
and from creates, typically done by
.B imap4d
(see
.IR ipserv (8))
and
.B pop3
(see
.IR mail (1))
whenever they are used to read someone's mail.
.PP
The remaining directories,
.BR allow ,
.BR block ,
.BR delay ,
.BR deny ,
and
.BR dial ,
represent the contents of the
.I classification 
(default
.BR /mail/lib/smtpd.conf.ext ).
Each contains two directories;
.B ip
and
.BR account .
The
.B ip
directory has the same open semantics as the 
.B trusted
directory, i.e., to check if an IP address falls
in that category, try to open a file whose
name is the IP address.
The
.B account
directory is similar but is used for matching
strings.  Each file in the directory represents
a regular expression.  To see if one of the
strings matches one of the regular expressions,
try to open the file whose name is the string.
If it succeeds, then there is a regular expression
that matches.  To determine the regular expression,
.B fstat
the open file.  The
.B name
field will be the regular expression.
.PP
There is a direct mapping from entries in
.I classification
and files under
.BR allow ,
.BR block ,
.BR delay ,
.BR deny ,
and
.BR dial.
A configuration file entry of the form:
.EX
	dial	135.104.9.0/24
.EE
corresponds to the file
.BR dial/ip/135.104.9.0#24 .
An entry of the form
.EX
	*block	.*!gre
.EE
corresponds to the file
.BR block/account/.*!gre .
.PP
Both the configuration file and control file formats
are described in
.IR smtpd (6).
.SH SOURCE
.B /sys/src/cmd/ratfs
.SH "SEE ALSO"
.IR mail (1)
.IR smtpd (6)
.IR scanmail (8)