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Printing and Linux

http://www.networkcomputing.com/showitem.jhtml?articleID=160910914&pgno=1

With back to school sales there are a lot of multifunction printers on the cheap. Essentially the Canon Pixma MP150 or HP PSC1410 are both offered for $89AUD. Generally, this will allow me to get rid of the current Canon scanner and Lexmark P707 combo I have at the moment and give back much need desk space. Given the lexmarks poor quality, annoying drivers and unreliability coupled with expensive cartridges is why I’m looking at the options available.

So a quick shopping list of what I need (no particular order)
– cheap cartridges
– ability to print in linux (although the print server is a Windows box, it is feasable that linux drivers can be avoided)
– good milleage on print media
– durable

The printer will, as it is currently, connected to the Windows machine. Laptop printing will be facilitated by Windows Networking.

Through my investigations I learnt that Epson and HP models are best for Linux printing. Although a little dated, this linuxprinting.org article about picking the best printer was helpful. Canon’s should be avoided like the plague.

That said, the thought entered my head about the Print Server taking on the task of preparing the print job. Perhaps the linux device would create the print job in a postscript format to which the Windows side would re-render and print the job. This means the linux support is indifferent (but inflexible, you can’t expedite a big print job by connecting your laptop directly to the printer and if the desktop is unavailable so is your printing).

In the article attached Windows to Linux Printing (and Vice Versa) explains about how to set something up along those lines, using CUPS and Samba. It also explains the difference between a print server, spooler, queue and how tasks are delegated between machines and the CUPS/Samba subsystems.

The most important concept is that in the ‘default’ networked printing environment, (platform independent), the client computer has the print drivers for the target printer installed and creates a RAW print file. When the file is ready, it is passed along the printer to the spooler and the spooler organises the printing of the document.

I thought I could implement this on my current setup before purchasing any hardware and learnt that I didn’t have to. Some clever monkey had built a Lexmark driver for the P707 based on the Z55 drivers lexmark have released.

No one had implemented drivers for new canon printers, even support from third party vendors such as TurboPrint and EPS was lacking.

Whilst HP didn’t support the printer directly, they do have drivers for the model down, PSC1400 and someone had used this to get a slowly working version going.

One side note to these requirements is to get a laser printer. The HP Laserjet 1020 is $149 AU and whilst it wouldn’t solve space problems. Again linux support is experimental but being a laser it would be more easy to support with a PCL/PPD type interface.

Decision forthcoming with the next edit. Its just good to know what is out there though.

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Netgear WGT634U – WPA-PSK & DHCP

Symptom: DHCP does not assign IP’s when router is using WPA-PSK encryption. ‘Limited or no-connectivity’ messages appear after a ~2 min timeout once wireless client initiates connection. This problem is intermittent and more predominant when the router is under heavy load – experienced whilst playing a video over LAN whilst downloading torrents.

Related Symptom: Wireless traffic at a standstill – ie, trying to set IP’s manually without using DHCP results in timeouts. Gateway address (usually 192.168.1.1 appears in ARP table but appears as invalid MAC addy 00-00-00-00-00-00.) Trying to set mac addy to IP of router statically still doesn’t work.

Suspecting:

  • WPA-PSK connections to this router are threatened when router is under heavy load.
  • New connections will fail as DHCP will not work – once you’ve disconnected, its difficult for the card to reconnect.
  • This problem affects a variety of routers. Even the Linksys WRT54G isn’t safe. See this search for more info.

About this setup

Firmware Version: 1.4.1.10

Hardware

  • WGT634U of course
  • DSL-302G w/DHCP in bridge mode connected to the Netgear’s Internet port.
  • All wireless cards below are affected
    • Intel 2100 B wireless mini-pci card
    • Netgear WG511U 108Mbps PCMCIA wireless card
    • Belkin 11Mbps PCI card
  • Lan connections from router to desktop, occasionally to the laptop (these are unaffected)

Operating Systems

  • Win XP Sp2
  • SUSE Linux 10

Known Workarounds

  • Use WEP based encryption and change your keys very frequently.
  • Powercycle all equipment (Netgears wizards / documentation indicate client computers should be rebooted when particular settings change – Why do they say this? What am I missing here that a regular enable/disable, clear ARP won’t fix?)
  • Use wired LAN to avoid encryption.
  • Modded firmware (OpenWGT, others?)

Stuff to Try

  • Initially (to replicate the problem and divide and conquer)
    1. Under WEP encryption, make all wireless clients use static addresses. (no dhcp)
    2. Switch to WPA encryption, clients still not using DCHP
    3. Continue using this sort of connection, operating the router under heavy load
    4. Hibernate PC, Awaken
    5. Should the connection drop and reconnect, check that traffic still runs thru that link
      1. If it doesn’t then the problem is not DHCP but WPA-PSK
      2. If traffic flows then DHCP w/WPA-PSK is the problem (have a feeling its not this one)
  • Other settings to try:
  • Long preamble – this is more to do with the initiating the connection
  • Slower speeds (11Mbps or lower?)
  • Reduce complex traffic as much as possible. Remove unnecessary protocols from the Network Connection
  • Switch on/off Adaptive Rate, Xtended Range
  • Issues about the router overheating due to power supply have been briefly mentioned in some forums (whirlpool, netgear’s support site). One user even mentioned that replacing the PSU with another routers one did the trick – will search for this one on request.
  • Use another device as the DHCP server (and maybe even the PPPoE to reduce load) – this would have to be the 302g moved to the Lan port
  • play with RTS/CTS fragmentation threshold (determines what type of wireless Collision Detection is used)
  • DHCP server on 302g could be interfering with server on WGT634U???
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Tool: Books: Alex Grey

A poster on alt.music.tool pointed out this little book regarding Alex Grey’s Lateralus work. It is soon to be released.

Amazon gift voucher is spent.

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Tool: ‘Schism’ And ‘Parabola’ DVDs Set For January Release

http://www.sonybmg.com.au/news/details.do?newsId=20030829002775

Needless to say I have mine already. JB-Hifi @ Chadstone had some import ones on sale for $17.99. Beats waiting around for tool army to process the online order and ship it.

As for the content, the menu’s have no writing (ala Salival) and the Dual commentary is very funny. The artwork is second to none.

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WPA passkeys don’t like ‘&’

I’ve been attempting to get Suse 10 working with my wireless network again after I upgraded the network security to WPA-PSK (TKIP).

Problem

  • Wireless network being detected in KInternet as a WEP network.
  • KInternet doesn’t appear to support WPA.
  • Unable to authenticate with Wireless network using WPA-PSK.

Most Importantly:

  • Ampersands in the WIRELESS_WPA_PSK setting of wireless interfaces config file (/etc/sysconfig/network/ifcfg-wlan-yourNICsMacAddy) can not have an ‘&’ character in them. Characters after the ‘&’ will be ignored.

Solution:

  • Configure your wireless interface in YAST such that it refers to the WPA-PSK network you are directly connecting to. For example, specify the SSID of the access point rather than ‘any’.
  • Disable KInternet from launching on KDE login.
  • Cleanup the wireless interfaces config file (/etc/sysconfig/network/ifcfg-wlan-yourNICsMacAddy), remove WEP passwords from the previous configuration.
  • Set USERCONTROLsetting to ‘no’. Disabling KInternet from launching at logon in Yast previously should have set this automatically.
  • In WIRELESS_WPA_PSK setting, precede the ampersand with the ‘‘ escape character.
  • Use hwdown / hwup to restart the interface.
  • Do an ifstatus interfaceName to ensure that the reconnection is successful.


Troubleshooting steps

  1. Read documentation for the hw{up, down, status} commands & ifcfg-wireless configuration file.
  2. Learnt that the paramater to use with hw… commands are the filenames found in /etc/sysconfig/hardware/hwcfg-*
  3. Opened a command shell, sudo as root user.
  4. Took down the device with /sbin/hwdown hwcfg-bus-pci-00:02:0a.0 (enter this command while your in the /etc/sysconfig/hardware directory so you can get tab completion to fill in the hwcfg name including escape sequences.
  5. Did a hwup (essentially this and the previous step give me a clean slate)
  6. Did an ifup-dhcp eth1
  7. Got the following

icarus-lx:/etc/sysconfig/hardware # /sbin/ifup eth1
eth1 device: Intel Corporation PRO/Wireless LAN 2100 3B Mini PCI Adapter (rev 04)
eth1 configuration: wlan-id-your:wNICs:MAC:addy
scripts/ifup-wireless: line 515: 2: command not found
eth1 starting wpa_supplicant
Line 7: Invalid passphrase length 7 (expected: 8..63) ‘charsUp‘.
Line 7: failed to parse psk ‘”charsUp‘.
Line 8: WPA-PSK accepted for key management, but no PSK configured.
Line 8: failed to parse network block.
Failed to read configuration file ‘/var/run/wpa_supplicant-eth1.conf’.
DHCP client is already running on eth1
ERROR: Warning: Could not set up default route via interface
Command ip route replace to default via 192.168.1.254 returned:
. RTNETLINK answers: Network is unreachable
Configuration line: default 192.168.1.254 – –
This needs NOT to be AN ERROR if you set up multiple interfaces.
See man 5 routes how to avoid this warning.

I’ve modified the output for security reasons, but just pretend in this case my WPA passkey is charsUp&BeyondTheAmpersand. The error message (Line 7:…) is telling me that the password is too short, rather that its not reading past the ampersand sign.

  1. Modified the /etc/sysconfig/network/ifcfg-wlan-00:00:00:00 with the correct password
  2. Bought down the interface with ifdown.
  3. Bought down the hardware device with hwdown
  4. Bought up the hardware device with hwup, which automatically does an ifup on the connected interface
  5. Do a ifstatus to verify that you are now connected to the network. The last few lines should look similiar to

    6. bssid=ap’s:mac:address
    ssid=apName
    pairwise_cipher=TKIP
    group_cipher=TKIP
    key_mgmt=WPA-PSK
    wpa_state=COMPLETED
    ip_address=ip.assigned.by.dhcp
    Supplicant PAE state=AUTHENTICATED
    suppPortStatus=Authorized
    EAP state=SUCCESS

Useful Commands
/usr/sbin/hwinfo – displays a list of hardware devices and the parent devices to which they are joined

Its worth noting I managed to get by with just the simple hwup, down, status & ifup-dhcp, ifdown, ifdown-dhcp and ifstatus commands to resolve the problem. /usr/sbin/iwconfig was not required.

Useful Files and Directories
/etc/sysconfig/hardware/hwcfg-…. – The filenames of the hardware config files. Specify this filename when running the hwup/down/status commands
/etc/sysconfig/network/ifcfg-wlan-… – The config files for the wireless interfaces

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Did Jesus exist? Court to decide

http://www.cnn.com/2006/WORLD/europe/01/04/italy.jesus.reut/index.html

Having just finished a stint of jury duty, I found it funny that this was going to court in Italy. I would like to see what evidence the church will present to prove ‘beyond reasonable doubt’ that Jesus existed in the form he claimed.