Manpages

NAME

hfaxd - Hyla FAX client-server protocol server

SYNOPSIS

/usr/sbin/hfaxd [ -d ] [ -q dir ] [ -o port ] [ -O ] [ -l bindaddress ] [ -i port ] [ -I ] [ -s port ] [ -S ]

DESCRIPTION

hfaxd is the Hyla FAX program that implements the server portion of:

Additional client-server protocols are planned and hfaxd is intended to be the ’’carrier’’ through which they are supported.

hfaxd is typically used in one of two ways; either as a standalone process that is started at system boot time to listen for client connections on one or more ports (in which case the -i, -o, or -s option must be used), or as a subservient process to the inetd(8) program. The two forms of use may however be combined so long as the same service is not provided both by the standalone hfaxd and through inetd.

HYLAFAX (NEW) CLIENT-SERVER PROTOCOL SUPPORT

If hfaxd is started with the -i option it will service clients using the Hyla FAX client-server protocol. This protocol is strongly related to the Internet File Transfer Protocol ( FTP ); so much so in fact that FTP client programs that include support for ’’quoted commands’’ may be used to communicate with hfaxd using the new protocol. (It should also be possible to use FTP -aware World Wide Web browsers such as Mosaic and Netscape Navigator to access Hyla FAX servers through the new protocol; but the current format for information returned in directory listings confuses them.)

The hfaxd server currently recognizes the following protocol requests; case is not distinguished. Entries marked with a ¹ can be used only when the client has established administrative privileges with ADMIN .

Request Description

The following non-standard or experimental commands are supported through the SITE request.

In addition FTP requests that are specified in Internet RFC 959 but not listed here are recognized, but not implemented.

The hfaxd server will abort an active data transfer only when the ABOR command is preceded by a Telnet "Interrupt Process" (IP) signal and a Telnet "Synch" signal in the command Telnet stream, as described in Internet RFC 959. If a STAT command is received during a data transfer, preceded by a Telnet IP and Synch, transfer status will be returned.

SIMPLE NETWORK PAGING PROTOCOL (SNPP) SUPPORT

If hfaxd is started with the -s option it will service clients using the Simple Network Pager Protocol ( SNPP ) as specified in RFC 1861 (which obsoletes RFC 1645).

The hfaxd server currently recognizes the SNPP protocol requests listed below. Requests marked with a ¹ are non-standard extensions to RFC 1861 that may be added to SNPP at some future time. Case is not distinguished and only the first four characters of requests are used in identifying commands.

The hfaxd server will abort an active SEND operation when an ABOR command is preceded by a Telnet "Interrupt Process" ( IP ) signal and a Telnet "Synch" signal in the command Telnet stream.

The following non-standard or experimental commands are also supported through the SITE request.

Note that hfaxd requires that SNPP clients login first with the LOGI directive while RFC 1861 permits clients to submit pages anonymously.

CLIENT ACCESS CONTROL

hfaxd controls client access according to the information in the file /var/spool/hylafax/etc/hosts.hfaxd. This file defines the set of users and machines that may receive service and, optionally, defines password challenges to use in authenticating clients. Clients may be permitted access to services with or without a password challenge. Access may also be restricted based on the host machine that a request for service originates from. Consult hosts.hfaxd(5) for information on the format and content of this file. The SITE ADDUSER protocol request is provided for adding new users to a server (available only to clients with administrative privileges).

Server resources are controlled based on clients’ identities. Jobs and documents, both received and submitted, are protected by the server. Typically clients are permitted access to anything they own or that is publicly accessible. There are also administrative privileges that clients may acquire and which permit them wide access to objects that reside on the server.

A complete client-server protocol specification is still outstanding.

hfaxd operates with its root directory set to the top of the Hyla FAX spooling area; /var/spool/hylafax. This is done so that clients see a virtual file hierarchy that is completely contained within the Hyla FAX operating environment on the server machine. Administrators however must be aware of this action when specifying files in the hfaxd configuration file: absolute pathnames relative to the root of the spooling should be used to specify filenames.

SERVER ACCESS CONTROL

The file /var/spool/hylafax/etc/shutdown, when present, specifies when to restrict access to a server machine. When this file is present and contains valid information hfaxd will permit only users with administrative privileges to access the server. Any other users that request service will be denied access and negative server responses will include any shutdown message specified in the shutdown file. Consult hylafax-shutdown(5) for information on the format and content of this file.

The SHUT protocol request can be used to schedule a server shutdown; it is available only to clients with administrative privileges. To make a shutdown server available again the shutdown file can be deleted with the DELE protocol request (this is to be replaced with an ’’unshut’’ protocol request so that implementation details are not part of the protocol).

CONFIGURATION FILES

hfaxd reads configuration information from the file /etc/hylafax/hfaxd.conf each time a new server process is started (i.e. for each new client). This file uses the same conventions used by other Hyla FAX configuration files; as described in hylafax-config(5). The following configuration parameters are recognized; items marked ’’( SNPP )’’ are used only by the SNPP support.

The configuration parameters are explained below:
AllowSortFormat

This controls whether the server accept the *SORTFMT commands which the client issues to change the server sort the listings.

FaxContact

The e-mail address to display as a point of contact in the help text returned to a client in response to the HELP or SITE HELP commands. By default this is ’’FaxMaster@hostname’’, where hostname is the fully qualified name for the machine where the server is running.

Format Description

The default format string is ’’%-7p %3l %8o %8s %-12.12m %.48f’’. It is recommended that all items include a field width so that client applications that construct headers from the format string can constrain the width of column title strings.

FileSortFmt

The format string to use when sorting the listing for directories using the LIST command. Follows the FileFmt formatting rules.

IdleTimeout

The initial/default timeout to use in timing out idle clients. This value defines the maximum amount of time (in seconds) that hfaxd will wait for a command from a client before terminating the connection. Unprivileged clients may alter the idle timeout up to the value of MaxIdleTimeout; privileged clients may set the timeout to any value.

Format Description

The default format string is ’’%-4j %3i %1a %6.6o %-12.12e %5P %5D %7z %.25s’’. This string constrains each status line to be less than 80 characters. It is recommended that all items include a field width so that client applications, such as faxstat(1) that construct headers from the format string can constrain the width of column title strings.

JobSortFmt

The format string to use when sorting the listing for jobs in the sendq and doneq directories. Follows the JobFmt formatting rules.

JobProtection

The file mode setting for job qfiles in the Hyla FAX queues (sendq and doneq). The default setting of ’’0644’’ allows all users to view all job parameters in the send/done queues. If PublicJobQ is set to false, then this file mode determines the permissions of the clients to see the jobs, following the Hyla FAX permission model of the group bits controlling uid permissions and the other bits controlling other permissions.

KillTimeMap

The mapping from SNPP service level (0-11) to job expiration time (kill time). A mapping is specified as a string of space-separate numbers where each value is the number of minutes to permit a job to run. The default mapping is ’’5 5 5 15 60 240 720 1440 1440 1440 1440 1440’’ which expires a job in 5 minutes for service levels 0-2, 15 minutes for level three, 60 minutes for level four, etc.

LogFacility

The symbolic name for the syslog(3) facility to use when logging error messages and informational/debugging messages requested through the ServerTracing parameter. The list of facility names is found in the system include file <syslog.h>; comparisons are case-insensitive.

MaxAdminAttempts

The maximum number of unsuccessful attempts gain administrative privileges with the ADMIN command that hfaxd will permit a client before terminating the connection. Note that the count of attempts is reset if/when the client successfully gains administrative privileges.

MaxConsecutiveBadCmds

The maximum number of consecutive unrecognized, unimplemented, syntactically incorrect, or otherwise unacceptable commands to permit a client before terminating the connection. This control has two purposes: to handle naive or malicious clients from sending long streams of nonsense commands to a server, and to insure that clients are forcibly terminated when a server is marked shutdown.

MaxIdleTimeout

The maximum value that a client may set the idle timeout to. This value is not enforced if the client has administrative privileges.

MaxLoginAttempts

The maximum number of unsuccessful attempts to login with the USER and PASS commands that hfaxd will permit a client before terminating the connection.

MaxMsgLength

The maximum number of characters to accept in a pager message specified with the DATA or MESS commands. Messages longer than this value are rejected.

Format Description

The default format string is ’’Modem %m (%n): %s’’.

ModemSortFmt

The format string to use when sorting the listsin for modem status information in the status directory.

PagerIDMapFile

The absolute pathname of the file that contains directions for mapping pager identifiers to IXO/TAP or UCP service providers (and optionally a pager identification number). Consult pagermap(5) for information on the format and content of this file. (Note that absolute pathnames are relative to the root of the spooling area).

PriorityMap

The mapping from SNPP service level (0-11) to job scheduling priority. A mapping is specified as a string of space-separate numbers where each value is the priority to assign to a job. The default mapping is ’’63 127 127 127 127 127 127 127 127 127 127 127’’ which assigns a high priority to service level zero and normal (default) priority to all other service levels.

PublicJobQ

By default, HylaFAX has always made the listings of the sendq/doneq include all jobs to any client connected to hfaxd. By setting this to false, hfaxd will also enforce it’s normal access restrictions on the listing of jobs in the sendq/doneq. These access restrictions are based on the file mode (see JobProtection ) and the logged in uid (see hosts.hfaxd )

PublicRecvQ

By default, HylaFAX has always made the listings of the recvq include all faxes to any client connected to hfaxd. By setting this to false, hfaxd will also enforce it’s normal access restrictions on the listing of faxes in the recvq. These access restrictions are based on the file mode faxgetty (and it’s related FaxDispatch ) set for the fax, and the logged in uid (see hosts.hfaxd )

Format Description

The default format string is ’’%-7m %4p%1z %-8.8o %14.14s %7t %f’’. This string constrains each status line to be less than 80 characters. It is recommended that all items include a field width so that client applications, such as faxstat(1) that construct headers from the format string can constrain the width of column title strings.

RcvSortFmt

The format string to use when sorting the listing for received facsimile in the recvq directory. Follows the RcvFmt formatting rules.

RetryTimeMap

The mapping from SNPP service level (0-11) to job retry time. A mapping is specified as a string of space-separate numbers where each value is the number of seconds to delay between delivery attempts. A value of zero causes retries to be scheduled using the default algorithm used by the Hyla FAX job scheduler. The default mapping is ’’30 60 60 180 0 0 0 0 0 0 0 0’’ which retries a level 0 job after a 30 second delay, levels 1 and 2 after 60 seconds, level 3 after 3 minutes, and other jobs are retried according to the usual scheduling algorithm.

ServerTracing

A number that controls the generation of tracing information by a server. areas that are individually controlled. To enable tracing of multiple areas of operation, the flag associated with each area should be bit-or’d to form the value for this tag.

Tracing messages are directed to syslog(3) using the facility specified with the LogFacility configuration parameter. Note that syslogd(8) must be configured to capture facility.info, facility.debug, facility.warning, and facility.err messages.

ShutdownFile

The absolute pathname of the server shutdown file; see hylafax-shutdown(5) for information on the format and content of this file. (Note that absolute pathnames are relative to the root of the spooling area).

UserAccessFile

The absolute pathname of the user access control file; see hosts.hfaxd(5) for information on the format and content of this file. (Note that absolute pathnames are relative to the root of the spooling area).

XferLogFile

The absolute pathname of the file to use for logging client-server file transfers (when enabled through the ServerTracing parameter). (Note that absolute pathnames are relative to the root of the spooling area).

OPTIONS

-l bindaddress

Bind to the specified bindaddress the tcp port. Please note that this argument need to be specified before the -i otherwise it will be ignored. A better approach to improve security would be to run hfaxd from xinetd, binding its service to the specific port. This will also make hylafax benefits from tcp wrappers and other options provided by xinetd.

DIAGNOSTICS

Diagnostics generated by hfaxd are logged using syslog(3).

FILES

/etc/hylafax/hfaxd.conf server configuration file

BUGS

To be filled in.

SEE ALSO

sendfax(1), sendpage(1), faxalter(1), faxrm(1), faxstat(1), faxq(8), syslog(3) hylafax-server(5), hosts.hfaxd(5), status(5), hylafax-shutdown(5),