Added info about data connection.

Henning Meier-Geinitz <henning@meier-geinitz.de>

doc/saned.man

@@ -1,4 +1,4 @@
-.TH saned 1 "06 Jan 2002"
+.TH saned 1 "07 Jan 2002"
 .IX saned
 .SH NAME
 saned - SANE network daemon
@@ -135,6 +135,13 @@ sane 6566/tcp # SANE network scanner daemon
 Note that port number 6566 has not been officially assigned to the
 SANE network protocol and may thus change in the future.
 .PP
+
+.SH "RESTRICTIONS"
+In addition to the control connection (port 6566) saned also uses a data
+connection. The port of this socket is selected by the operating system and
+can't be specified by the user currently. This may be a problem if the
+connection must go through a firewall (packet filter).
+
 .SH FILES
 .TP
 .I /etc/hosts.equiv