SMTPFWDD(8)

NAME
smtpfwdd - SMTP proxy (server portion)

SYNOPSIS
smtpfwdd

DESCRIPTION
The Firewall Toolkit smtpfwdd proxy is an application level proxy that provides configurable access control and logging mechanisms. The smtpd client proxy together with the smtpfwdd server proxy, which run on the firewall, transfer mail between internal and external mail servers, using rules you supply.

All packets, and therefore all application requests go to the firewall. On the firewall, the smtpd and smtpfwdd proxy software relay information from one side of the firewall to the other. They prevent versions of sendmail on the external network from talking with versions of sendmail on the internal network, and vice versa. No IP packets pass from one side of the firewall to the other. All data is passed at the application level.

The server portion of the SMTP proxy (smtpfwdd) generally runs as a daemon (invoked from /etc/rc.local). Periodically, based on a configurable value (by default every 60 seconds), the server daemon (smtpfwdd) wakes up and checks to see if there is any new mail that the SMTP client proxy (smtpd) has placed in the spool directory. The smtpfwdd daemon checks the headers of the mail for formatting problems. It then calls the configured message transfer agent (usually ssmtp sendmail emulator) for final delivery

OPTIONS

  Command Line Options
None.

  Configuration Options
The smtpfwdd proxy reads configuration rules from the /usr/local/etc/netperm-table. It reads all rules using the smtpfwdd , smapd and * (wildcard) keywords. The smtpfwdd proxy reads the netperm-table from top to bottom. If there are multiple rules in the table that could apply for a particular attribute, the smtpfwdd proxy uses the first one that it finds. See netperm-table(5) for a more complete explanation of netperm-table syntax and precedence. smapd configuration options are included for TIS fwtk compatibility.

The smtpfwdd proxy recognizes the following attributes:

badadmin user
    Specifies the username to which the smtpfwdd server forwards mail that it cannot deliver.

    user
        Specifies a user name or alias.

baddir directory
    Specifies the directory in which the smtpfwdd server places any spooled mail that it cannot deliver normally.

    directory
        Specifies a directory on the same device as the spool directory. Do not include a trailing slash (/) character. Ensure that this directory has the same owner and permission as the normal directory that smtpd uses.

directory directory
    Specifies the directory that the smtpfwdd proxy makes its root directory before providing service.

groupid group
    Specifies the name of the group the smtpfwdd proxy uses when running.

    group
        Specifies either a name or numeric id from the /etc/group file.

maxchildren children
    Specifies the maximum number of child processes the smtpfwdd server can fork to handle mail.

pidfilefile
    Specifies a file name where daemon stores master process PID.

sendmail program
    Specifies an alternate path for ssmtp, or another mail delivery program you are using to deliver your mail inside your perimeter.

userid user
    Specifies the user ID the proxy uses when running.

    user
        Specifies either a name or numeric id from the /etc/passwd file.

wakeup seconds
    Specifies the number of seconds that the smtpfwdd server sleeps between scans of the spool directory. If no value is specified, smtpfwdd uses a default value of 60 seconds.

EXAMPLES
This example places the undelivered mail in the /var/spool/smtpd/badmail directory:

    smtpfwdd:  baddir /var/spool/smtpd/badmail

FILES

/etc/rc.local
    Command script that controls automatic reboot, and includes startup information for the smtpfwdd proxy.

/usr/local/etc/netperm-table
    The network permissions file contains configuration information for the Firewall Toolkit, including the smtpfwdd proxy.

/var/spool/smtpd
    The directory that the smtpfwdd proxy uses as its root directory.

BUGS
Report bugs to arkenoi@gmail.com or fwtk-users@buoy.com mailing list. Include a complete example, explaining what you expected to happen and what actually happened. Be sure to indicate the type of system (operating system, hardware, etc.) you are using, as well as the version of the smtpfwdd proxy.

AUTHOR
Obtuse Systems Corporation.

SEE ALSO
netperm-table(5), rc(8), smtpd(8)