[Discuss] CUPS Remote Printer

[John Blomfield]

Murray Strome wrote:
> John Blomfield wrote:
>> Murray Strome wrote:
>>> My main printer is an Okidata OL600e B&W LED printer which is 
>>> physically connected to my wife's printer.  Through new installs, 
>>> upgrades, etc. I have never really had to do much to have it 
>>> accessible to all my computers.  However, since re-installing 
>>> Kubuntu on my wife's computer, I cannot no longer access it.  I 
>>> imagine that it has something to do with my ability to access her 
>>> computer. I have not changed any settings in my routers. The 
>>> simplified configuration is:
>>>
>>>
>>>    --------                   --------------- ----              
>>> --------------------
>>>   | router|------------- |  Computer 1  |----------|Okidata Printer|
>>>   |           |----             -------------------             
>>> --------------------
>>>   ----------     |
>>>                    |                          ---------------        
>>> ---- --------------               |  router #2 |------|  Computer 2 |
>>>         ----------------        --------------------   Of course, 
>>> there are other computers connected to router & router 2, and other 
>>> printers on both Computer 1 and Computer 2. The first router is 
>>> connected to a cable modem box, then to Shaw cable.
>>>
>>> All the computers used DHCP to get their addresses, as do the 
>>> routers.  I have changed Computer 1 to fixed address (one the router 
>>> originally assigned to it), but that did not make any difference.
>>>
>>> From Computer 2, I can ping router or Computer 1 (or anything else 
>>> connected on that router) from Computer 2. I can ping router 2 from 
>>> Computer 1 using the address "leased" to it by router, but I cannot 
>>> ping to Computer 2 from Computer 1.  I can connect to the internet 
>>> from everywhere without any problem.  If I try to add a network CUPS 
>>> printer in Computer 2, it cannot access Port 631 on the address 
>>> assigned to Computer 1 by router.
>>>
>> You need to open the router #2 firewall so that computer 1 can see 
>> computer 2.  It depends on the brand of router and its software how 
>> you do this.  Have a look and the firewall rules for router #2, it 
>> should have a menu item that allows you to do this.  As a last resort 
>> you could put Computer 2 in the DMZ (Demilitarized Zone) as it would 
>> still be protected by the other router.  Incidentally why do you need 
>> router #2 would not a switch do just as well unless it has to be 
>> secure from Computer 1 and the others on router?
>>
>> John Blomfield
> I am not sure HOW to open router #2 firewall so that computer #1 can 
> see computer 2. Router #2 is a Trendnet TEW-432BRP. I see a setting on 
> the Trendnet to enable DMZ but it wants a DMZ host IP; what would that 
> be, or is that what I should be doing?
>
> The reason I am using router #2 is that two of my computers are in 
> another room, quite far from the cable modem.  I had run one ethernet 
> cable through the walls to that room, but it was enough of a chore to 
> do so that I did not want to run another one (besides, all the ports 
> on the first one were in use).  I tried to use a wireless card for the 
> second computer, which worked (sort of) on one of the computers if I 
> used Windows XP on it, but I could never get a very good signal, and I 
> was never able to get it working with LINUX.  There was a very good 
> price on the Trendnet (cheaper than another cable), and it did the 
> trick without any effort until now.
>
> Murray
>
Since there is no security issue with router 2 network computers you can 
try this way.  Set the range of DHCP on Router 1 to say 192.168.0.2 to 
192.168.0.10 and the range of Router 2 DHCP from 192.168.0.11 to 
192.168.0.20 (the first three groups of numbers i.e 192.168.0 may be 
different on your routers), then again in Router 2 look for the "Inbound 
Filter Rules" and "enable" the range the to 192.168.0.11 to 192.168.0.20 
and set the action to "Allow".  This should allow computer 1 to see 
computer 2 through the firewall.  Depending on the router software it 
may not be as obvious as this, you may have to set the something like 
this WAN * to LAN * "Allow" meaning all data from the WAN side (which is 
in your case not a WAN but Router 1) and * meaning everything is allowed 
to the LAN side (meaning in your case Computer 2 and others) and again * 
meaning everything.  The problem is that every router software is 
different even among routers from the same manufacture depending on age 
so its hard to be specific with out seeing your actual router software 
interface.

To try the DMZ approach you must set you Computer 2 in the router to a 
fixed IP address and then set the DMZ host to that IP address but make 
sure its different from the range of addresses served by Router 1.  You 
can set the IP address range for Router 2 to practically anything that 
falls within the guide lines e.g 192.168.2.0 - 255.

John Blomfield