When Print-server not found on network, cups-manager crashes

(In reply to comment #0)
> I configured my network with shared printing. I found out that I had not opened
> the right ports on my print server, but the real problem was that cups-manager
> hanged

This is really a problem of how TCP is designed. If you completely block packets
to the right port, your computer will not get any ICMP message that the port is
invalid, and thus will get the usual 30 second timeout. Does it recover after 30
seconds?

> and even crashed Firefox when I tried to print a page

That's more serious. That means you tried to print something in Firefox?

(In reply to comment #1)
> (In reply to comment #0)
> > I configured my network with shared printing. I found out that I had not opened
> > the right ports on my print server, but the real problem was that cups-manager
> > hanged
>
> This is really a problem of how TCP is designed. If you completely block packets
> to the right port, your computer will not get any ICMP message that the port is
> invalid, and thus will get the usual 30 second timeout. Does it recover after 30
> seconds?
>
> > and even crashed Firefox when I tried to print a page
>
> That's more serious. That means you tried to print something in Firefox?
>
>
Thank you very much for the reply.

Here is a Scenario I did, hopefully to make it clearer.:
1. I followed the guide http://occy.net/printing. Configured the
/etc/cups/cupsd.conf on the server and /etc/cups/client.conf on the client as
described in the guide.
2. Blocked port 631 on print server
3. Started 'gnome-cups-manager' from terminal, and intended to test for about 15
minutes
 Result: - Network card increases activity a little bit and continues
    After 7-8 minutes an error message appeared:
    ** (gnome-cups-manager:25187): WARNING **: IPP request failed with status 1280
    ** (gnome-cups-manager:25187): WARNING **: IPP request failed with status 1280
4. I started firefox, then chose file - printer. It hangs, hand I have to quit
firefox with "killall firefox-bin". That did not happend with OpenOffice.org 2
beta 2, when I chose "file - print" from the menus.

Last time I tested gnome-cups-manager I tested for about 5 minutes, then no
error message appeared. Should not the error message appear a little earlier
than 7-8 minutes? And should not I be able to start gnome-cups-manager even if
it cannot find the network printer? What if I move the PC somwhere else and
intend to use another printer, cups-manager will not even start then without
configuring client.conf, I guess. Anyway Firefox hangs/crashes, I don't know if
this is a firefox issue, or a firefox/gnome-cups issue.

5. I open port 631 on the print server:
 Result: I am able to open gnome-cups-manager and firefox does not crash when I
chose "file -print".

Note to myself: Let's see how cups 1.2 performs, it has an overhauled way of
detecting printers.

1.2 rc2 packages available, needs testing
https://lists.ubuntu.com/archives/ubuntu-devel/2006-April/017211.html

Do you still have this problem in current dapper?

Thank you for working on this bug report, I appreciate it. I have been
testing my printserver again, running
Dapper on both server and client:

Scenario 1:
1. Added line "ServerName <IP to printserver>" into client.conf of the
non-server PC.
2. Try to print a page from Firefox without blocking port 631 on server.
Result: OK.
3. Port 631 of printserver blocked.
4. Starts sudo gnome-cups-manager in terminal. Result: Nothing starts. Error
message after about
   5-10 minutes: ** (gnome-printer-view:16910): WARNING **: IPP request
failed with status 1280
5. Try to print a page from openoffice.org 2.0.2. Result: Openoffice.org
2.0.2 crashes. Need to "force quit".
6. Try to print a page from Firefox 1.5.0.3. Result: Firefox
1.5.0.3crashes. Need to "force quit".

Comment: Basically the same result as last time with breezy. On the other
hand, I do not need to add "servername ipadress" to client.conf anymore, so
it is not an issue for me now. Looks like the Cups version of Ubuntu Dapper
detects network printers more easily.

Scenario 2:
1. Did not add anything to client.conf. Just started gnome-cups-manager.
Detected the LAN-printer automatically.
2. Print a page from Firefox and Openoffice.org without firewall blocking
port 631 on the server. Result: OK.
3. Print a page from Firefox and Openoffice.org when firewall blocking port
631 on the server. Result: No crash of Firefox and Openoffice.org. No error
message within 15 minutes, even if it failed to print.

Comment: It does not seem to crash Firefox and Openoffice.org when I did not
edit the client.conf by myself. On the
other hand it should, in a perfect world, have returned an error message.

On 10/05/06, Martin Pitt <email address hidden> wrote:
>
> Do you still have this problem in current dapper?
>
> --
> When Print-server not found on network, cups-manager crashes
> https://launchpad.net/bugs/21993
>

I had a similar bug. When the bug occurred I had a ServerName listed in my /etc/cups/client.conf that was nonexistent/inaccessible . I commented out the SeverName line in the client.conf file and this bug disappeared.

And oh by the way, I am running a completely update version of Feisty and still encouter this issue.

PS. if anyone knows how to open up port 631 in windows it would be a big help.

I see the problem in a new install of 7.10 Gutsy Gibbon as well - ServerName points to a printserver at work, I'm at home, I try to print, and it hangs (completely, no X updates at all) for a long time (more than 5 minutes) but then comes up with a print dialog that only lists postscript/default [which is fine, it's the delay that's the problem...] lsof shows the IPP connection in SYN_SENT (ie. it's not getting connection refused, it's getting nothing at all, as in a down machine or firewall. A misconfigured client.conf could probably do that too...) After printing to file it appears that it is trying to contact the server again, leading to a similar hang.

Mark, are you seeing this with system-config-printer on 7.10 or are you still running gnome-cups-manager? We have changed the default print management system in Ubuntu from gnome-cups-manager to system-config-printer because g-c-m is no longer maintained.

I'm guessing this is a different problem (it's also a hang rather than a crash). Could you please file a new bug against system-config-printer if you are still seeing this? Thanks!