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HylaFAX The world's most advanced open source fax server


Revision as of 21:31, 12 December 2005 by (talk)

This is a living list of frequently asked questions about the FlexFAX/HylaFAX fax software system. The point of this document is to circulate existing information, and to avoid rehashing old answers. Better to build on top than start again. Please read this document before posting to the HylaFAX mailing list.

The HylaFAX software and this FAQ were created by Sam Leffler. From November 1995 the FAQ was maintained by Matthias Apitz who signficantly expanded the material. Since January 1997, however, the FAQ has been dormant and as a result, become out of date, and some places, misleading. The process of updating the FAQ started in late 1999 on an irregular basis by the web team. Until this process is complete, it is advisable to check the information here by searching the mailing list archives.

Your comments, additions and fixes to the FAQ are welcome: please send them to You can also give feedback on specific questions through links provided on each individual page. If you cannot find the information you need here or in the archives, please subscribe to the community mailing list and ask for help there.


What is HylaFAX?

See About HylaFAX for more information.

Where did HylaFAX/FlexFAX come from?

Whay is it called HylaFAX?

The name of this software package is "HylaFAX", not "hylafax", "Hylafax", or anything else. Also, do not call this software by its old name "FlexFAX" because that name is a trademark of another fax product and the folks that own that trademark are possessive. Please also note that "HylaFAX" is a trademark of Silicon Graphics and it should be treated as such when used in documentation.

Regarding the name, it is derived from the word hyla which is defined as "Any of a genus of (Hyla) of frogs, especially the tree frog." Hence the logo found on the home page for this software.

Finally, please recognize that this is free software that represents the work of many people. The section of "Acknowledgements" lists those people that have made significant contributions.

Why should I use HylaFAX instead of some other fax package?

HylaFAX is designed to be very robust and reliable. The fax server is designed to guard against unexpected failures in the software, in the configuration, in the hardware, and in general use. HylaFAX uses an intelligent scheduling policy that attempts to recognize different types of failures and optimize retry attempts. An important design goal is that users must never worry about transmit jobs being lost or mishandled: jobs are either completed successfully or the submitter is notified what happened to their job and why the job failed. If you are willing to shepherd your facsimile transmissions then other software packages may be more suitable for you.

HylaFAX supports a wide variety of modems and is designed to support any Class 1, Class 2, or Class 2.0 modem without modification to the source code. If you have a modem that provides only a Class 1 interface then HylaFAX is likely to be the only freely available software package that will work with your modem.

HylaFAX supports multiple modems and heavy traffic load. If you expect to send or receive more than 1 or 2 facsimile a day, then HylaFAX is likely to be the best package for you to use.

HylaFAX is expressly designed to be highly configurable without modification or access to the source code. The software comes with extensive documentation to assist in understanding how the software functions and how to configure it.

HylaFAX is freely available. There is no GNU copyleft policy. There are no requests for remuneration, constraints on use, or constraints on incorporation into products (compare this with other "freely available fax packages"). There are binary distribution packages or other formats for several Unixes.

Which modems can I use with HylaFAX?

HylaFAX is intended to be used with fax modems. Fax modems are not the same as data modems though most contemporary data modems also include support for fax communication. HylaFAX should work with any Class 1, Class 2, or Class 2.0 fax modem. Wherever possible HylaFAX works around known modem problems or restricts modem usage in order to provide a functioning system.

See Handbook:Choosing a modem for more information.

What machines does HylaFAX run on?

HylaFAX is intended to run on any UNIX system that supports a particular set of features: FIFO special files, BSD-style sockets and the TCP/IP communication protocols, BSD-style file locking (flock) or equivalent functionality from which it can be emulated (fcntl, lockf), and POSIX 1003.1-style interfaces, including termios for manipulating tty devices.

The following systems are known to have these features: AIX v3.x, v4.x BSD/386, FreeBSD, HP-UX 9.x, 10.x IRIX, ISC4.0, Linux, OSF/1 V1.3 and V3.0, SCO 3.2v4 with TCP/IP, SCO ODT 3, SCO 5.0, Solaris 2.x, SunOS 4.1.x, SVR4.x on an Intel x86 and MIPS (UnixWare, Onsite, SINIX, ...), Ultrix 4.4.

How to tell which HylaFAX version you have?

If you have need to refer to this specific software, you should identify it as:

HylaFAX v<version><n>

where <version> is found in the file VERSION and <n> is the number recorded in dist/hylfax.alpha. This string is also prominently displayed when you run the configure script to setup the software for compilation and each time the faxq scheduler process is started (look in the file where syslog messages are recorded).

What documentation is available?

HylaFAX™ comes with extensive documentation in two forms: this HTML-based documentation that is designed for on-line use and general guidance, and a complete set of UNIX manual pages that contain reference information in a more terse but precise format. The HTML documentation contains links to the manual pages providing a complete hypertext connection between the two forms of documentation.

The HylaFAX documentation is intended to support users of binary distributions; it is complete enough that access to the source code is not needed.

How should I report bugs?

Unconfirmed HylaFAX bugs and related questions should be sent by mail to the HylaFAX mailing list

Confirmed bugs and discussion items regarding security or technical-level matters should either be sent by mail to the HylaFAX development mailing list or posted directly to HylaFAX Bugzilla,

When corresponding about the software please always specify:

  • What version of HylaFAX you have
  • What compiler (including version) your are using
  • What system you are running on: system type and OS version
  • What kind of modem and the modem firmware revision
  • A description on how to reproduce the problem
  • A minimal trace log that shows your problem

For example: "HylaFAX v4.0pl2 under Solaris 2.3 with gcc 2.7.2; ZyXEL 1496E with 6.11a firmware."

Do not send large trace log or PostScript files to the mailing list; the list is quite large.

Do not send traces with binary i/o or timer tracing.

Do not send traces without time-stamps and do not remove lines in the trace.

Can I run HylaFAX on my NT/Windows Server?

Date: Tue, 10 Dec 1996 07:49:56 +0100 (MET) From: Matthias Apitz < > Subject: Re: HylaFax

>Mark Bradley wrote:

>Can I run HylaFax on my NT 4.0 Server? >S.Mark Bradley >Compucare Services

NO. (NT is not the answer, it's the question and the answer is NO :-))


Is HylaFAX able to receive/send 1000s of faxes/day?

answer needed

Building From Source and Installation

Sending Faxes

How do I print a watermark on my faxes?

Thorsten Garrels wrote:

> I'd like to have a kind of "static" graphic in the background of every
> page hylafax sends. This could be a company-logo, for instance but as
> well a complete "letter-template". Insteed of printing the text via a
> printer on this template you should be able to "print" your text
> directly on a virtual paper which already contain the company logo and
> locations.

Date: 13 March 2000 18:46
From: Frank Terhaar-Yonkers <>
Subject: Re: flexfax: background graphic for every sent page

What you want is a "watermark." This little postscript snippet prints CONFIDENTIAL diagonally across the page:

/wp$y 792 def
/wp$x 612 def
%-------Customize Here-------
/font /Helvetica-Bold def
/pointsize 96 def
/text1 (CONFIDENTIAL) def
%-------End Customization----
/center {dup stringwidth pop
2 div neg 0 rmoveto} def
wp$x 2 div wp$y 2 div pointsize 2 div sub moveto
.85 setgray
font findfont pointsize scalefont setfont
45 rotate
0 0 text1 center ashow

Merge something like this (a exercise left to someone else) with the postscript sent to Hylafax.

- Frank

Running a HylaFAX Server

"Service not available, remote server closed connection?"

> After running
> faxmodem to setup my modem, I run faxstat to make sure that it's up, and
> receive the following msg:
> Service not available, remote server closed connection
> Telneting in to the machine on port 4559 gets a "Connection closed by
> foreign host." message.

Looks like hfaxd(1) isn't running on your machine. You have to make sure that hfaxd(1) and faxq(1) is running before you get any decent response with faxstat(1).

Do I have to restart a server after changing the modem config file?

No. The HylaFAX servers will re-read a config file (if needed) before each send and on any reset. This means you only need to explicitly restart a server if you change it before doing a receive. You can also avoid restarting it if you use cu/tip to talk to the modem since this will cause the server to wakeup and then reset itself when you exit from cu/tip.


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