> The current situation is that printing works on #1, where the > printer is -- and not from the others. > > - Ok, here is the deal. Configure all the printers on the server. On the clients do no configuration at all ,none. And you will be able to print to all the printers. Any configuration you do on the clients will undoubtedly screw things up. One exception. In the /etc/cups/client.conf file you can fill in the ServerName line with the address of the server. Leave the admin boxes alone.

I have just hit major weirdness. On machine #1, where I just installed telnet an hour or so ago, and where it ran but failed to connect, I've just tried again with a new target -- and suddenly bash doesn't see telnet any more! ===== ===== ===== ===== [btth@Hbsk2 ~]$ telnet 192.168.a.b 631 Trying 192.168.a.b... telnet: connect to address 192.168.a.b: No route to host [btth@Hbsk2 ~]$ ssh 192.168.a.b btth(a)192.168.a.b's password: Last login: Thu Oct 30 09:51:51 2008 from 192.168.a.q [btth@Msgv ~]$ telnet 192.168.a.c 631 -bash: telnet: command not found

Björn Persson wrote: > 1: Check that Cups is actually listening on the network. Run this command > as root on the machine where the printer is: > > netstat --inet --inet6 --listen --program --numeric | grep cupsd > > Does it say "192.168.x.y:631" or "127.0.0.1:631"? Isn't it easier just to say telnet 192.168.a.b 631 Doesn't this tell you if you are connected to the CUPS server much more simply?

I've been advised, more or less btw in an otherwise scarcely related thread, to quit using my KVM switch (which has spare USB ports touted by the maker especially for printserving) as a printserver. So I plugged the printer (an HP psc 1315v) into my #1 machine; and I've been telling Firefox 127.0.0.1:631 on each of the machines, and trying to get it to work.

This is the second half of a reply to Craig White's post below, put into a new thread because it has departed so far from the original topic. I'm discovering great new stuff -- new to me, that is -- and I want to draw maximal attention to it from others who may be in shoes like mine. On Mon, 03 Nov 2008 15:08:11 -0700, Craig White wrote: [...] > I fear that you still don't get it. > > This is a rather cool blog about 'Trivial uses for Telnet'... > http://evolvedcode.net/content/doc_alttelnet/ > > which talks about how to use telnet client application to connect to a > web server or a pop3 server or an smtp server and talk to the server as > if you were just another application communicating with that server so > you can test things out or just familiarize yourself with the process > itself. Indeed! I just sang its praises in the first half of this reply, on the original thread. > Obviously telnet to the cups port (631) is very much similar as the > others (SMTP/POP3/HTTP) except that like the others, the cups server has > its own vocabulary. Ah, if only I had known, back when I was teaching baby language courses, what vast argots the various branches of Computer Science would develop -- once it came into existence, of course. > In essence, every time you open a web browser and tell it to go to a > specific web site, you are doing something similar to opening a > connection to that web site with telnet on port 80 (ignoring of course > the web browser rendering engine, javascript, etc.). Ignoring a lot of things I wouldn't know if they bit me never mind where, to be sure. But in the present context, there seem to be some I can't ignore -- some that (afaict) reflect the settings on my terminal, and some that are apparently matters of notation and vocabulary. Thus for instance, following along the second paragraph, about NetCat -- or rather, trying to follow -- I get this : ===== ===== ===== ===== telnet> NC -v -v {address} {port}^[[D^[[D^[[D^H^H^H^H^H^[[3~^C [btth@Hbsk ~]$ telnet telnet> ^[[A^[[D^C [btth@Hbsk ~]$ NC -v -v 192.168.0.8 631 bash: NC: command not found [btth@Hbsk ~]$ telnet telnet> NC -v -v 192.168.0.8 631 ?Invalid command telnet> NC -v -v {192.168.0.8} {631} ?Invalid command telnet> ===== ===== ===== ===== If only by trial and error, I think I can set up a different terminal emulation (xterm instead of my usual gnome terminal, for instance, which is configured primarily for Alpine), and avoid all that gibberish caused by trying to use the backspace and arrow keys. But it isn't obvious to me, unless I haven't had enough coffee yet, why the last two commands are both invalid. All that's obvious is that, despite Mr. Welsh's exemplary lucidity, I am reading his text otherwise than he expects.

1: Check that Cups is actually listening on the network. Run this command as root on the machine where the printer is: netstat --inet --inet6 --listen --program --numeric | grep cupsd Does it say "192.168.x.y:631" or "127.0.0.1:631"?

I fear that you still don't get it. This is a rather cool blog about 'Trivial uses for Telnet'... http://evolvedcode.net/content/doc_alttelnet/ which talks about how to use telnet client application to connect to a web server or a pop3 server or an smtp server and talk to the server as if you were just another application communicating with that server so you can test things out or just familiarize yourself with the process itself.

Obviously telnet to the cups port (631) is very much similar as the others (SMTP/POP3/HTTP) except that like the others, the cups server has its own vocabulary.

In essence, every time you open a web browser and tell it to go to a specific web site, you are doing something similar to opening a connection to that web site with telnet on port 80 (ignoring of course the web browser rendering engine, javascript, etc.).

Beartooth: > Let me see if I have this straight. Having done most of the two > footnoted parts above (maybe all -- I tried to), I *think* I can just > go from client to client, deleting *all* printers (if all will let me; > last time I tried that, as I said above, there was one that seemed > immortal, afaict). If desperate, one could go into /etc/cups/ and remove the entries for particular printers. I'm not sure how it handles missing files, but you could load the file and remove all the configuration data, leaving just the two comment lines at the top of printers.conf.

> If/when I get the present entries deleted, they will presumably > once again find my wife's printer downstairs. They did last time, > doubly : once as a printer and once as a fax. Does it hurt to have that > there? Should I re-delete it, or maybe go shut her machine down (she's > out of town) before I start telling clients to find printers? I can't see a problem with their being a paper printer and a fax printer on the list, unless they're named so badly that you can't pick the right one, but a rename would sort that out. If that computer's not in use, you could remove it from the equation while you set the rest up. Tim: >> * On my LAN, all the PCs are trusted explicitly, so I took the easy >> option of setting the firewall to trust eth0 as a whole, rather than >> particular ports. > I did that, iiuc : marked both eth0 and ippp+ as trusted on all > clients and on the server. I wouldn't go marking ppp as trusted, that's the interface to the world. That's throwing the firewall away, completely.

>> ** Share out that printer to the LAN but it doesn't need sharing to >> the internet, unless you have a mixture of different isolated subnets, >> where that option will allow crossing from one subnet to another. > I don't have such complications -- it's all one plain LAN, without > subnets. But I don't follow how I share it only to the LAN -- unless > that's what trusting eth0 and ippp+ do, perhaps?? CUPS has two administration options in this area, share printers (to the local network), and allow printing from the internet (share it to anyone and everything). The first will only allow printing within the boundary of what's considered the local network. Firewall configuration is a separate issue. Allowing *connections* between interfaces and ports, and where the allowing and disallowing happens (with the local network, and the external network, separately). > We don't normally fax things, nor receive faxes; but I can easily > imagine it becoming convenient to be able to print to one another's > printers, for instance if one breaks down or runs out of ink/ > toner/whatever. Otoh, it sounds like a large can of worms ... Or, if one printer has features that the other does not (colour, double-sided, collating, etc.), or you're going to print something intended for the other person (it can sit in their printer out tray). There's a plethora of reasons why you might do that. On the other hand, if you have one printer that you want to be able to use anywhere, and another that will only be used with the computer it sits next to, then share out the first one, and don't share the second one. > I haven't (yet, at least) done a thing about my wife's machine nor > printer -- not made it either a client or a server. So, that's still got the factory pre-configuration, so to speak? In that case, I'd leave it alone while you play with the rest of your network, and you can *look* at what it does as you go along. >> Having said that, if you're reconfiguring a system which already had >> printers configured all over the place on the clients, you'd want to >> remove all those configurations, and then let them find the servers by >> themselves, again. > Hmmm ... Does that mean I need to go reconfigure my wife's CUPS > in any case?? Now I'm confused. If you hadn't done anything to it before, why would you need to now?

If only by trial and error, I think I can set up a different terminal emulation (xterm instead of my usual gnome terminal, for instance, which is configured primarily for Alpine), and avoid all that gibberish caused by trying to use the backspace and arrow keys.

On Tue, 04 Nov 2008 06:01:49 +1030, Tim wrote: [...] >> I didn't mean to imply that I was going to install >> telnet-server. > > Actually, you do. Since without it, there'd be no way to telnet into > the box and do that. It's the telnet server that gives you a command > line interface when you telnet into the box. Then I won't telnet into the box. After all, I never have.

> It certainly *can* hurt to have a telnet server on a machine, or even > use telnet across an insecure network.

Of course. But I'm thinking of times like the many recently, when one or another of my none too new machines couldn't cope at all, at all, with my new wide monitor. Getting to init3 requires a reboot, afaik -- especially in a case such as this, when the machine seems blind and deaf to both the keyboard and the mouse; getting into system-config-display a/o xorg.conf with ssh or telnet (IF the latter could) would be quicker. I didn't mean to imply that I was going to install telnet-server.

It can, of course, and has several times. That's how I know that such things can save me. What I was trying to say was that it couldn't hurt to have another way also available.

I should have asked sooner. Why can't ssh get you to a machine without an X-server?

Beartooth wrote:

> [btth@Msgv ~]$ telnet 192.168.a.c 631 -bash: telnet: command not found > ===== ===== ===== =====

If this occurred to me I would start by re-booting.

Incidentally, you have to put in the correct IP address of your server - 192.168.a.b was just supposed to be an indicator.

Mikkel L. Ellertson wrote: > Oops - type. It should be: > ippd://<address>:631/<something> > not > ippd://<address>/631/<something> Actually, CUPS suggests ipp:// not ippd . Also CUPS does not give the :631 for this protocol, only for http://<IP address>:631/ . Probably it doesn't matter?

[btth@Hbsk2 ~]$ telnet 192.168.a.b 631 Trying 192.168.a.b... telnet: connect to address 192.168.a.b: No route to host [btth@Hbsk2 ~]$ ssh 192.168.a.b btth(a)192.168.a.b&#39;s password: Last login: Thu Oct 30 09:51:51 2008 from 192.168.a.q [btth@Msgv ~]$ telnet 192.168.a.c 631 -bash: telnet: command not found [btth@Msgv ~]$ telnet 192.168.a.c 631 -bash: telnet: command not found [btth@Msgv ~]$ telnet 192.168.a.c 631 -bash: telnet: command not found [btth@Msgv ~]$ ===== ===== ===== ===== In between those, I ran rpm -q telnet on a different gnome- terminal tab, and then "yum install telnet" again on a root tab. Both assured me telnet was there.

On Sat, 01 Nov 2008 09:41:14 -0800, Mike Wright wrote: >Beartooth wrote: [...] >> How then can you get a client without a server? If I let yum >>install this one thing, is there then (only then) a way to split it and >>get rid of half? Remember I neither have nor am likely to acquire the >>savvy to handle electronic attacks. > >There are different packages: telnet (the client) and telnet-server. Oho! Then all those who said "get rid of telnet" really *meant* "get rid of telnet-server." Right? So does that mean I should run "yum install telnet" on all machines? With the server on none? Or only the client on only the machine with the printer? What responds to "telnet 192.168.a.b 631" on a machine with no telnet at all? For that matter, what about "ssh 192.168.a.b 631" instead? I am at least relatively familiar with ssh.

On Sat, 01 Nov 2008 11:26:06 -0500, Mikkel L. Ellertson wrote: > Beartooth wrote: >> On Sat, 01 Nov 2008 15:40:42 +0000, Timothy Murphy wrote: >> >>> Isn't it easier just to say >>> telnet 192.168.a.b 631 >>> Doesn't this tell you if you are connected to the CUPS server much >>> more simply? >> >> I take care not to install telnet, or to remove it if anaconda >> installs it. >> > The telnet client is handy to have. The telnet server is the one you > would normally want to remove. Apps like pirut and the packagekit give me only a single choice, telnet or no telnet, without any indication of role; and rpm -q says "not installed." So I had supposed, absent any indication to the contrary, that it was a single package, comprising if not functioning as both a server and a client -- and nobody ever told me "Get rid of telnet server," but simply "Get rid of telnet." Also, if I plug the numbers in to "telnet 192.168.a.b 631" I get an error saying "command not found." If I try "yum install telnet-client" or "...telnet_client," or "...telnetclient," I get a message saying no such package is available. If I put a space between the words, as if telnet and client were two apps, it tells me client is not available, and offers to install telnet -- one unitary thing. How then can you get a client without a server? If I let yum install this one thing, is there then (only then) a way to split it and get rid of half? Remember I neither have nor am likely to acquire the savvy to handle electronic attacks.

Beartooth wrote: > On Sat, 01 Nov 2008 15:40:42 +0000, Timothy Murphy wrote: > >> Isn't it easier just to say >> telnet 192.168.a.b 631 >> Doesn't this tell you if you are connected to the CUPS server much >> more simply? > > I take care not to install telnet, or to remove it if anaconda > installs it. > The telnet client is handy to have. The telnet server is the one you would normally want to remove.

On Sat, 01 Nov 2008 15:40:42 +0000, Timothy Murphy wrote: > Isn't it easier just to say > telnet 192.168.a.b 631 > Doesn't this tell you if you are connected to the CUPS server much more > simply? I take care not to install telnet, or to remove it if anaconda installs it.

Mikkel L. Ellertson wrote: > If you are using the CUPS web administration, look at the "Device > URI:" line. One should be a USB device, and one an > ippd://<address>:631/<something> - the ipp:// one should be the > default on all but the machine with the printer attached. Dear Mikkel, Are you suggesting one should use the ipp:// URI rather than http:// ? I always use the http one, on the grounds that I've heard of http . Is there really any difference? I assume one is not really using http, just the protocol.

It's a pity CUPS gives an inordinately long URI for USB printers.

> This used to be the case. Unfortunately, starting with Fedora 9, the > minimum that is now needed on the clients has changed from "none" to:

Not true. One always had to have the appropriate port open.

On Fri, 31 Oct 2008 14:22:18 +0000, Tim Waugh wrote: > On Fri, 2008-10-31 at 08:50 -0500, Aaron Konstam wrote: >> Ok, here is the deal. Configure all the printers on the server. On the >> clients do no configuration at all ,none. And you will be able to print >> to all the printers. > > This used to be the case. Unfortunately, starting with Fedora 9, the > minimum that is now needed on the clients has changed from "none" to: > > * enable Network Printing Client (IPP) packets through the firewall by > selection System->Administration->Firewall, selecting the "Network > Printing Client (IPP)" check-box and clicking Apply. WOW!! What a difference! I did that on machine #2 (only, so far). When I click on Printers, I see what the machine thinks are *nine* : my wife's downstairs is there twice, once as itself and once with "-fax" appended to it. All the other seven are my one machine, once as default with my name for the machine it's on, but no IP; the others have either an IP or some other indication where they are; I'm seeing it double on #1 (as default and not), and double on #4 (with its same correct IP both times, not together); sometimes it shows as published, sometimes not. I tried to print the router's table, with IP and MAC numbers, from a browser (Konqueror, despite the fact i run Gnome); but it just asked me if the printer were connected. Iiuc, I should go do the same on the other two clients (machine #3 and #4, no printer attached), but *not* on #1, which does have the printer, and must therefore be acting as the server. Right?

On Thu, 30 Oct 2008 22:44:19 +0100, Björn Persson wrote: > 1: Check that Cups is actually listening on the network. Run this > command as root on the machine where the printer is: > > netstat --inet --inet6 --listen --program --numeric | grep cupsd > > Does it say "192.168.x.y:631" or "127.0.0.1:631"? No, neither. [root@Hbsk2 ~]# netstat --inet --inet6 --listen --program --numeric | grep cupsd tcp 0 0 0.0.0.0:631 0.0.0.0:* LISTEN 2526/cupsd tcp 0 0 :::631 :::* LISTEN 2526/cupsd udp 0 0 0.0.0.0:631 0.0.0.0:* 2526/cupsd [root@Hbsk2 ~]#

> 2: Do you have a packet filter ("firewall") on the machine where the > printer is? Have you opened the IPP ports in the packet filter? How do I tell?

Lacking the skills to be sure whether I've been cracked, let alone those to recover, I try to be paranoid; I install denyhosts, for instance, and likely other defenses that don't spring to mind.

Also, the router that my ISP supplies (Netgear MBR 814) supplies several kinds of defenses, which I have tried to set with caution. When I want to do bittorrent, for instance, I have to go change the router settings for a while. (I try to leave them changed long enough to give back more that I take, before I change them back; but I haven't actually used the torrent in months, so they are probably tight.)

On Fri, 2008-10-31 at 08:50 -0500, Aaron Konstam wrote: > Ok, here is the deal. Configure all the printers on the server. On the > clients do no configuration at all ,none. And you will be able to print > to all the printers. This used to be the case. Unfortunately, starting with Fedora 9, the minimum that is now needed on the clients has changed from "none" to: * enable Network Printing Client (IPP) packets through the firewall by selection System->Administration->Firewall, selecting the "Network Printing Client (IPP)" check-box and clicking Apply.

On Thu, 30 Oct 2008 21:29:41 +0000, James Wilkinson wrote: [...] > May I recommend you start here? Find out which one of these entries > works, use it, and delete the other. Don’t look into network printing > until you’ve got local printing working reliably. > > Having two entries for the same printer on the same computer is an > opportunity for both CUPS and you to get confused.¹ > > Once you’ve got local printing working, then you may want to start from > scratch on other PC, so you know you’re sharing the printer entry that > works. [...] > ¹ There are sometimes good reasons for doing so, mind, but that’s more > advanced stuff. Yes, somebody else recommended that, and I did it as soon as I was sure he meant it. The current situation is that printing works on #1, where the printer is -- and not from the others. -

May I recommend you start here? Find out which one of these entries works, use it, and delete the other. Don’t look into network printing until you’ve got local printing working reliably. Having two entries for the same printer on the same computer is an opportunity for both CUPS and you to get confused.¹ Once you’ve got local printing working, then you may want to start from scratch on other PC, so you know you’re sharing the printer entry that works.

¹ There are sometimes good reasons for doing so, mind, but that’s more advanced stuff.

On Wed, 29 Oct 2008 15:48:27 -0500, Mikkel L. Ellertson wrote: > You should be able to administer all the CUPS setups from one > machine, I tried that again this morning. No joy. If I type http://192.168.x.y:631/admin into firefox on 192.168.x.z, I get a 503 from privoxy : connect failed.

OK, I know what infinite regression is, but not enough about how printing (let alone print serving) works to see how it does that. So which should be unchecked, on which machine? My guess is that the one with the printer should be different, but I don't know in what way.

Strange that you have 2 entries. On the machines without the printer, you should be using the on that has: Device URI: ipp://<something>

You may have to make the changes I listed in another e-mail - the one describing what checkboxes to make sure are checked.

On the machine with the printer attached, try printing a test page on each printer, and see what works best. Set that as the default, and remove the other printer.

Then move on the setting the other versions of CUPS.

You should be able to administer all the CUPS setups from one machine,

and you should see an ipp:// printer on all the machines that do not have a printer attached.

Once you have things working the way you want, you should be able to delete all the usb://hp/psc%201310%20series?serial=CN4AIC71YKO2 and the hp:/usb/psc_1310_series?serial=CN4AIC71YKO2 entry on all except the machine with the printer attached.

If you are using the CUPS web administration, look at the "Device URI:" line. One should be a USB device, and one an ippd://<address>/631/<something> - the ipp:// one should be the default on all but the machine with the printer attached.

Beartooth wrote: > On Wed, 29 Oct 2008 14:59:56 -0500, Mikkel L. Ellertson wrote: > >> Dumb question - is the new printer connection set as the default >> printer? I am guessing that the USB connection through the KVM switch >> was the default printer on each machine. > > I think so. They all show it twice, in fact : as psc-1310- > series-, and either the same with underlines instead of hyphens, or > with a "2" at the end. > > I've just tried the troubleshooter on two or three of the > machines, against each iteration of the printer, and gotten reports, > but no solution. > If you are using the CUPS web administration, look at the "Device URI:" line. One should be a USB device, and one an ippd://<address>/631/<something> - the ipp:// one should be the default on all but the machine with the printer attached.

On Wed, 29 Oct 2008 14:59:56 -0500, Mikkel L. Ellertson wrote: > Dumb question - is the new printer connection set as the default > printer? I am guessing that the USB connection through the KVM switch > was the default printer on each machine. I think so. They all show it twice, in fact : as psc-1310- series-, and either the same with underlines instead of hyphens, or with a "2" at the end. I've just tried the troubleshooter on two or three of the machines, against each iteration of the printer, and gotten reports, but no solution.

I've been advised, more or less btw in an otherwise scarcely related thread, to quit using my KVM switch (which has spare USB ports touted by the maker especially for printserving) as a printserver. So I plugged the printer (an HP psc 1315v) into my #1 machine; and I've been telling Firefox 127.0.0.1:631 on each of the machines, and trying to get it to work. I thought I had it; and when I print at all, it's most often from Alpine 2.0. So I've been trying to print one Alpine message from each machine. One at least told me the printer seemed not to be connected. The others have adamantly done nothing. Since all I know of printing would go in a gnat's eye, and Alpine has several printing options (none of which I understand well), my first thought is to try to find out if I have a pure Alpine problem, a pure CUPS problem, or something else. Can anybody tell??

Let me see if I have this straight. Having done most of the two footnoted parts above (maybe all -- I tried to), I *think* I can just go from client to client, deleting *all* printers (if all will let me; last time I tried that, as I said above, there was one that seemed immortal, afaict).

If/when I get thepresent entries deleted, they will presumably once again find my wife's printer downstairs. They did last time, doubly : once as a printer and once as a fax. Does it hurt to have that there? Should I re-delete it, or maybe go shut her machine down (she's out of town) before I start telling clients to find printers?

> * On my LAN, all the PCs are trusted explicitly, so I took the easy > option of setting the firewall to trust eth0 as a whole, rather than > particular ports.

I did that, iiuc : marked both eth0 and ippp+ as trusted on all clients and on the server.

> ** Share out that printer to the LAN but it doesn't need sharing to the > internet, unless you have a mixture of different isolated subnets, where > that option will allow crossing from one subnet to another.

I don't have such complications -- it's all on plain LAN, without subnets. But I don't follow how I share it only to the LAN -- unless that's what trusting eth0 and ippp+ do, perhaps??

We don't normally fax things, nor receive faxes; but I can easily imagine it becoming convenient to be able to print to one another's printers, for instance if one breaks down or runs out of ink/ toner/whatever. Otoh, it sounds like a large can of worms ...

I haven't (yet, at least) done a thing about my wife's machine nor printer -- not made it either a client or a server.

> Having said that, if you're reconfiguring a system which already had > printers configured all over the place on the clients, you'd want to > remove all those configurations, and then let them find the servers by > themselves, again.

Hmmm ... Does that mean I need to go reconfigure my wife's CUPS in any case??

Ok, here is the deal. Configure all the printers on the server. On the clients do no configuration at all ,none. And you will be able to print to all the printers. Any configuration you do on the clients will undoubtedly screw things up. One exception. In the /etc/cups/client.conf file you can fill in the ServerName line with the address of the server. Leave the admin boxes alone.