Re: [hylafax-users] Question concerning Client - Server connection

[Joe Phillips <jaiger@acm.org>]

On Tue, 2003-02-25 at 18:01, Hugo Wau wrote:

> Port 4559 and port 4557 are opened for udp and tcp client-server
> communication.  Are there any other ports, needed for hylafax
> client-server communication?

The short answer is 'yes', there are other ports that HylaFAX clients
use.

> When I issue a fax from a client machine I get the error:
> 425 Cannot build data connection: Connection refused.
> Any tip? What should I try to issue a fax from a client machine?

To understand the source of your problem, read up on the FTP protocol
relative to firewalls.  This type of issue is a *very* frequent FAQ on
this list.  You should be able to find more details in the archives for
this list.

<sidebar> Can we please please add this to the FAQ if it does not
exist?  My quick scan of the 'Troubleshooting' section of the FAQ didn't
find this question.  Is it answered in the FAQ?  If not, I volunteer to
write the first revision of the answer as I am tired of seeing this
question. </sidebar>

Two quick things to try are:

1- try to use "passive mode" like you would in FTP - I'm unsure if the
HylaFAX clients allow passive mode.  I know other clients (like those
built upon my gnu.hylafax library) do.

2- if your firewall software has ftp connection tracking features, read
the documentation and enable it for inbound connections for port 4559
(in addition to, or instead of 21, the standard FTP port) to the HylaFAX
server.  I have not done this recently but had it working fine with
ipfwadm and Linux some years ago.

If the above do not work, to prove your HylaFAX server works remotely,
and if your security policies can permit, remove/disable firewalling
between your test client and server (temporarily/permanently completely
or on a per-host basis) - only do this if you understand the security
implications fully.

good luck,

-joe


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