Bug 549065

Because of
https://bugzilla.novell.com/show_bug.cgi?id=468426#c8
there is currently in yast2-printer only a static
text regarding firewall in the dialogs as follows:

In the "Print via Network" dialog
the static text directly in the dialog reads:
----------------------------------------------------------
If a firewall is used, check that incomming packages
on UDP port 631 are allowed.
----------------------------------------------------------
and the help text reads:
----------------------------------------------------------
Regarding firewall:
Check if a firewall is active for a network zone
in which printers are published via network.
By default the SuSEfirewall allows any incomming information
via a network interface which belongs to the 'internal zone'
because this zone is trusted by default.
If the remote CUPS servers and your system are in
an internal network and when you trust all what there is
in your internal network, your network interface must be set
to be in the 'internal zone'.
It does not make sense to have a network setup in a trusted
internal network with a network interface which belongs
to the untrusted 'external zone' which is the default setting
for network interfaces to be safe.
Do not disable firewall protection for CUPS
(i.e. for IPP which uses TCP port 631 and UDP port 631)
for the untrusted 'external zone'.
----------------------------------------------------------

In the "Share Printers" dialog
the static text directly in the dialog reads:
----------------------------------------------------------
If a firewall is used, check that remote access to CUPS
is allowed via IPP on port 631.
----------------------------------------------------------
and the help text reads:
----------------------------------------------------------
Regarding firewall:
Check if a firewall is active for a network zone
in which printers are made available via network
to be used by trusted users
(nobody lets arbitrary users print on his printer).
By default the SuSEfirewall allows any access via
a network interface which belongs to the 'internal zone'
because this zone is trusted by default.
If the CUPS server and the client systems are in an
internal network and when you trust all what there is
in your internal network, your network interface must be set
to be in the 'internal zone'.
It does not make sense to have a network setup in a trusted
internal network with a network interface which belongs
to the untrusted 'external zone' which is the default
setting for network interfaces to be safe.
Do not disable firewall protection for CUPS
(i.e. for IPP which uses TCP port 631 and UDP port 631)
for the untrusted 'external zone'.
----------------------------------------------------------

From my point of view sufficient information is there
BUT
some/many/almost-all? usres do not notice and/or read it.

Therefore I think about an enhancement to make the firewall
issue more noticeable by the user.

Basically the idea is that a popup is gets hopefully
better awareness than just static text or help text.

But I do not want to show a popup in any case regardless
if actually a firewall is used because popups without
a reason are an annoyance.

Because of bug #468426 I do no longer like to call
the yast firewall module only to find out if a firewall
is used or not (I do not want to find if and out how
exactly the yast firewall module could tell me if
any kind of firewall is used - not only the SuSEfirewall
but also whatever selfmade set of iptables rules).

Therefore I think about a simple command line test like
  test "$( iptables -n -L | wc -l )" -gt "10" && echo firewall active
or perhaps even better
  iptables -n -L | egrep -q 'DROP|REJECT' && echo firewall active
to find out if any kind of firewall is used.

Note that because of
https://bugzilla.novell.com/show_bug.cgi?id=468426#c8
"firewall check would not make much sense"
such a popup would be shown additionally to the static
text in the dialog.