February | 2015 | Fitzcarraldo's Blog

Using a Samsung Xpress C460FW with Gentoo Linux and Android KitKat for printing and scanning

February 24, 2015 3 Comments

INTRODUCTION

A work colleague has just received a Samsung Xpress C460FW MFP (laser printer, scanner, copier and fax machine) for small print jobs. It is possible to connect to it via USB, Direct USB, wired network, wireless network, Wi-Fi Direct and NFC; that’s impressive for a MFP that can be purchased for GBP 270 in the UK.

I wanted to use the C460FW to print and scan from my laptop running Gentoo Linux, and also to print and scan from my Samsung Galaxy Note 4 running Android KiKat. It turned out that I was able to do all of those, and it was not difficult to set up.

A technician from the IT Support department had already entered a static IP address, subnet mask and default gateway IP address via the C460FW’s control panel to connect it to the office’s wired network. So my options to connect to this particular C460FW are: the wired network for Linux; Wi-Fi Direct for Linux and Android; NFC for Android.

I had never used Wi-Fi Direct before, but it turned out to be easy in Gentoo Linux on my laptop, and also easy in Android KitKat on my Samsung Galaxy Note 4. I had never used NFC before either, and that also turned out to be easy on my Samsung Galaxy Note 4.

Samsung has a series of videos on YouTube explaining how to use Wi-Fi Direct and NFC for printing, scanning and faxing with the C460FW from a Samsung smartphone; here are links to a few of them:

Samsung Smart Printing – 01 NFC Connect

Samsung Smart Printing – 02 Wi Fi Direct

Samsung Smart Printing – 03 Wi Fi

Samsung Smart Printing – 04 NFC Print

Samsung Smart Printing – 05 NFC Scan

Samsung Smart Printing – 06 NFC Fax

Samsung Smart Printing – 11 Samsung Mobile Print App(Printer Status)

PRINTING

Linux

Wired connection

I had installed the package net-print/samsung-unified-linux-driver Version 1.02 from a Portage local overlay back in March 2013 when I needed to print to a different model of Samsung MFP, so I thought I would see if that driver would work with the C460FW. I opened the CUPS Printer Manager in a browser window (http://localhost:631/) to configure my Gentoo installation to print to the device via the wired network. ‘Samsung C460 Series‘ was in the list of discovered network printers in the CUPS Printer Manager, and the driver ‘Samsung C460 Series PS‘ was displayed at the top of the list of models, so it was a piece of cake to set up the printer via CUPS, and I was able to print a test page in no time at all. My colleague uses a laptop running Windows 7, and he had to install the Windows driver from a Samsung CD that came with the C460FW.

Wireless connection

As the IT Support technician had configured the C460FW to print via the office wired network rather than the office wireless network, I decided to configure my laptop to print via Wi-Fi Direct, just to learn about Wi-Fi Direct, really. On the C460FW’s control panel I selected Network > Wireless > Wi-Fi Direct and enabled Wi-Fi Direct. Scrolling through the Wi-Fi Direct entries in the LCD I saw the following information:

Device Name: C460 Series
Network Key: <an 8-digit code>
IP address: 192.168.003.001

Two new networks were listed under ‘Available connections’ in plasma-nm (the KDE GUI front-end to NetworkManager) on my laptop: ‘DIRECT-HeC460 Series‘ and ‘DIRECT-SqC460 Series‘, both using WPA2-PSK encryption. I used the control panel of the C460FW to print a network configuration report in order to check which of the two SSIDs I should select, and it is ‘DIRECT-HeC460 Series‘ (I found out later that an adjacent room also has a C460FW and its Wi-Fi Direct SSID is ‘DIRECT-SqC460 Series‘). So I selected ‘DIRECT-HeC460 Series‘ and plasma-nm prompted me to enter a network password. I entered the 8-digit key I had found from the C460FW’s LCD panel (it’s also listed in the printed network configuration report), and NetworkManager connected to the printer.

In exactly the same way as I do when setting up any printer in Linux, I launched Firefox, opened the CUPS Printer Manager page, clicked on ‘Administration’ > ‘Add Printer’ and entered the user name ‘root’ and the password in the pop-up window. Again the ‘Add Printer’ page had ‘Samsung C460 Series‘ in the list of discovered network printers, so I just selected it and clicked on ‘Continue’. As I had already set up the printer in CUPS for the wired network connection and given it the name ‘Samsung_C460FW_office‘, I entered the name ‘Samsung_C460FW_office_WiFi_Direct‘ to distinguish it from the wired network entry, entered a Description and Location, and clicked on ‘Continue’. The next page had ‘Samsung C460 Series PS‘ first in the driver list so I selected that, clicked on ‘Add Printer’ and that was it. I was able to print a test page from the CUPS Printer Manager, and the printer is now included the list of printers in Linux applications’ print dialogues.

When I want to print using Wi-Fi Direct the only thing I need to remember to do first is select ‘DIRECT-HeC460 Series‘ in the network GUI on the KDE Panel, so that the connection is active when I click ‘Print’ in whichever application I want to print from.

Given the ease of printing via the wired network and Wi-Fi Direct, I have no doubts that printing would also work had the C460FW been configured for the office wireless network instead of the wired network.

Duplex printing

The only downside to the Samsung Xpress C460FW is that it only supports manual duplex printing. If you specify duplex printing when printing from Windows, Samsung’s Windows driver prints all the odd-numbered pages in reverse order and displays a message in Windows telling you what to do next (turn over the pile of paper and put it back in the paper tray!), but in Linux it’s not difficult to work out what you have to do: you simply have to print all the odd-numbered sides first, turn over the paper, then print all the even-numbered sides. The print dialogue in Linux applications gives you the option to print only odd-numbered pages or only even-numbered pages, so there is no problem. The print dialogue in some Linux applications allows you to print pages in reverse order as well but, if not, you have to reverse the order yourself before printing the even-numbered pages (i.e. put Page 1 face down at the top of the pile then Page 3 face down under it, and so on). It’s not a big deal unless the document has a large number of pages.

Android

As you would expect with devices from the same manufacturer, setting up my Samsung Galaxy Note 4 to print with the Samsung Xpress C460FW via WPS (Wi-Fi Protected Setup) was easy. When I selected ‘Print’ on the Galaxy Note 4, it gave me the option to print via wireless network or Wi-Fi Direct. I chose the latter and, as I had already enabled Wi-Fi Direct on the C460FW’s control panel, the printer name was displayed in the list of available devices. I selected it, a blue LED began flashing on the C460FW’s control panel and the LCD prompted me to press the WPS button (on the left of the control panel). As soon as I pressed that, the C460FW printed the document sent by my Galaxy Note 4. From then onwards, I just needed to select ‘Print’ on the Galaxy Note 4, select the printer from the list of available devices, and the document is printed. When I want to print using Wi-Fi Direct the only thing I need to remember to do first on the Galaxy Note 4 is select ‘DIRECT-HeC460 Series‘ as the Wi-Fi network.

NFC

I then decided to try to print using NFC. I placed the Galaxy Note 4, without Wi-Fi enabled and with the Home Screen displayed (not the Lock Screen), on the NFC label on top of the C460FW; Android launched Play Store and prompted me to install Samsung Mobile Print, which I did. Now when I place the Galaxy Note 4 on the NFC label, the Galaxy Note 4 automatically enables Wi-Fi, connects to the C460FW directly and displays the Mobile Print app showing the options Print, Scan and Fax, and a page of icons labelled: Gallery, Camera, Google Drive, E-mail, Web page, Document, Facebook, DropBox, Evernote, OneDrive and Box, as well as a Settings icon to configure the printer (paper size etc.). I am able to select a document, photograph, Web page, etc. on the Galaxy Note 4 and print it. It is also possible to launch the Mobile Print app first and then place the Galaxy Note 4 on the C460FW.

NFC is not entirely trouble-free, though. Sometimes the Galaxy Note 4 displays a ‘Device not found‘ message but I can still print. Sometimes the Galaxy Note 4 displays the message ‘Connecting printer. There was some error while connecting to this device. Check your printer and try again. If NFC Pin was changed then please enter new NFC Pin.‘ and the two devices will not connect. Powering off then on the C460FW solves that. Sometimes the Galaxy Note 4 connects to another wireless network instead of to the C460FW via Wi-Fi Direct and the Samsung Galaxy Note 4 then has to disconnect automatically from the other network. Sometimes the C460FW prompts me to press its WPS button and the Galaxy Note 4 then connects via Wi-Fi Direct but the Mobile Print app then displays the error message ‘Device not found. To troubleshoot please check – C460 Series is powered on. – Wi-Fi direct is enabled on C460 Series. – C460 Series and Mobile are connected to the same network.‘. Again, powering off then on the C460FW solves that. Despite these hiccups, printing via NFC is still handy.

SCANNING

Linux

I found out how to get the C460FW scanner working by consulting the third-party Web site The Samsung Unified Linux Driver Repository which someone created to provide .deb packages for the Samsung driver as well as tips on how to get Samsung printers and scanners working in Linux. It turned out to be relatively straightforward to scan, both via the office wired network and via Wi-Fi Direct. I edited the file /etc/sane.d/xerox_mfp.conf and replaced the following:

#Samsung C460 Series
usb 0x04e8 0x3468

with the following in order to use the C460FW to scan via the office wired network:

#Samsung C460 Series
#usb 0x04e8 0x3468
#Wired network static address of this C460FW:
tcp 10.90.21.125

or with the following in order to use the C460FW to scan via Wi-Fi Direct:

#Samsung C460 Series
#usb 0x04e8 0x3468
#Wi-Fi Direct address of this C460FW:
tcp 192.168.3.1

I found the IP addresses from the network configuration report I printed earlier.

I was able to use the two Linux scanning applications I normally use, XSane and gscan2pdf, to scan via the wired network and via Wi-Fi Direct. The resulting scans were very good. Given the ease of scanning via the wired network and Wi-Fi Direct, I have no doubts that scanning would work via a wireless network had the C460FW been configured for the office wireless network instead of the wired network.

Android

To use NFC to scan a document I place the Galaxy Note 4, without Wi-Fi enabled and with the Home Screen displayed (not the Lock Screen), on the NFC label on top of the C460FW. The Galaxy Note 4 enables Wi-Fi, connects automatically to the C460FW directly and launches the Mobile Print app showing the options Print, Scan and Fax. It is also possible to launch the Mobile Print app first and then place the Galaxy Note 4 on the C460FW. In other words, the procedure is exactly the same as when wanting to print via NFC. If I select Scan, the Galaxy Note 4 displays buttons for previewing and scanning. Amongst other things, the app’s Settings menu allows you to select whether you want to save the scanned image as a JPEG, PNG or PDF file. The hiccups mentioned above when printing via NFC also apply to scanning. Nevertheless, scanning from the C460FW to the Samsung Galaxy Note 4 via NFC is still handy.

CONCLUSION

As I am mainly interested in printing text documents I have only tried to print a few colour photographs on plain copier paper, and they look good. Text in documents looks crisp. Despite the lack of automatic duplex printing the C460FW is an excellent peripheral, especially for the price, although I don’t pay for the consumables so I have no idea of the operating costs. The ease with which I got it printing and scanning in Gentoo Linux (laptop) and Android KitKat (Samsung Galaxy Note 4) means that I would definitely consider purchasing this model for home use.

Filed under Android, Gentoo Linux, Hardware, Linux, Networks, Wired, Wireless Tagged with Android, Ethernet, Firefox, Galaxy Note 4, Gentoo Linux, GUI, KDE, laptop, Linux, networks, printer, Samsung, scanner, wired, wireless, Xpress C460FW

Downloading YouTube video or only audio

February 18, 2015 Leave a comment

One of my favourite Linux applications is the command-line utility youtube-dl, which I use quite often to download YouTube videos or extract only the audio, either for leisure or work purposes.

Downloading a video

Copy the URL of the YouTube video from the browser’s address bar. I’ll use the video ‘Como fazer um bom churrasco de Picanha‘ as an example.
Ascertain the types and resolutions available for that particular video:

$ youtube-dl -F https://www.youtube.com/watch?v=8BuQCD8eh9k 8BuQCD8eh9k: Downloading webpage 8BuQCD8eh9k: Extracting video information 8BuQCD8eh9k: Downloading DASH manifest [info] Available formats for 8BuQCD8eh9k: format code extension resolution note 171 webm audio only DASH audio 118k , audio@128k (44100Hz), 5.05MiB 140 m4a audio only DASH audio 129k , m4a_dash container, aac @128k (44100Hz), 5.99MiB 141 m4a audio only DASH audio 256k , m4a_dash container, aac @256k (44100Hz), 11.90MiB 160 mp4 256x144 DASH video 111k , 15fps, video only, 5.03MiB 242 webm 426x240 DASH video 190k , 1fps, video only, 7.19MiB 133 mp4 426x240 DASH video 248k , 30fps, video only, 11.33MiB 243 webm 640x360 DASH video 378k , 1fps, video only, 13.83MiB 134 mp4 640x360 DASH video 465k , 30fps, video only, 12.98MiB 244 webm 854x480 DASH video 744k , 1fps, video only, 27.11MiB 135 mp4 854x480 DASH video 873k , 30fps, video only, 25.98MiB 247 webm 1280x720 DASH video 1378k , 1fps, video only, 49.45MiB 136 mp4 1280x720 DASH video 1837k , 30fps, video only, 58.40MiB 17 3gp 176x144 36 3gp 320x240 5 flv 400x240 43 webm 640x360 18 mp4 640x360 22 mp4 1280x720 (best)
Chose which video resolution you would like to download. For example I’ll download the highest resolution available for this particular video (Format 22, which is a 1280×720 MPEG-4 file):

$ youtube-dl -f 22 -o Como_fazer_um_bom_churrasco_de_Picanha.mp4 https://www.youtube.com/watch?v=8BuQCD8eh9k 8BuQCD8eh9k: Downloading webpage 8BuQCD8eh9k: Extracting video information 8BuQCD8eh9k: Downloading DASH manifest [download] Destination: Como_fazer_um_bom_churrasco_de_Picanha.mp4 [download] 100% of 83.77MiB in 07:09

Extracting audio from YouTube videos

Let’s say you just want an audio file of the video’s sound track. There are several options, so I’ll just show a few simple examples here:

MP3 file at default quality:

$ youtube-dl --extract-audio --audio-format mp3 -t https://www.youtube.com/watch?v=8BuQCD8eh9k 8BuQCD8eh9k: Downloading webpage 8BuQCD8eh9k: Extracting video information 8BuQCD8eh9k: Downloading DASH manifest [download] Destination: Como fazer um bom churrasco de Picanha-8BuQCD8eh9k.m4a [download] 100% of 11.90MiB in 00:56 [ffmpeg] Correcting container in "Como fazer um bom churrasco de Picanha-8BuQCD8eh9k.m4a" [ffmpeg] Destination: Como fazer um bom churrasco de Picanha-8BuQCD8eh9k.mp3 Deleting original file Como fazer um bom churrasco de Picanha-8BuQCD8eh9k.m4a (pass -k to keep)

You can see from the console output above that youtube-dl downloads an M4A file and then uses ffmpeg to convert it to the audio file type you specified. You can check the file’s properties:

$ file Como\ fazer\ um\ bom\ churrasco\ de\ Picanha-8BuQCD8eh9k.mp3 Como fazer um bom churrasco de Picanha-8BuQCD8eh9k.mp3: Audio file with ID3 version 2.4.0, contains: MPEG ADTS, layer III, v1, 64 kbps, 44.1 kHz, Stereo
MP3 file of 128 kbps:

$ youtube-dl --extract-audio --audio-format mp3 --audio-quality 128K -t https://www.youtube.com/watch?v=8BuQCD8eh9k 8BuQCD8eh9k: Downloading webpage 8BuQCD8eh9k: Extracting video information 8BuQCD8eh9k: Downloading DASH manifest [download] Destination: Como fazer um bom churrasco de Picanha-8BuQCD8eh9k.m4a [download] 100% of 11.90MiB in 01:23 [ffmpeg] Correcting container in "Como fazer um bom churrasco de Picanha-8BuQCD8eh9k.m4a" [ffmpeg] Destination: Como fazer um bom churrasco de Picanha-8BuQCD8eh9k.mp3 Deleting original file Como fazer um bom churrasco de Picanha-8BuQCD8eh9k.m4a (pass -k to keep) $ file Como\ fazer\ um\ bom\ churrasco\ de\ Picanha-8BuQCD8eh9k.mp3 Como fazer um bom churrasco de Picanha-8BuQCD8eh9k.mp3: Audio file with ID3 version 2.4.0, contains: MPEG ADTS, layer III, v1, 128 kbps, 44.1 kHz, Stereo
M4A file at best quality available for that particular video:

$ youtube-dl --extract-audio --audio-format best -t https://www.youtube.com/watch?v=8BuQCD8eh9k 8BuQCD8eh9k: Downloading webpage 8BuQCD8eh9k: Extracting video information 8BuQCD8eh9k: Downloading DASH manifest [download] Destination: Como fazer um bom churrasco de Picanha-8BuQCD8eh9k.m4a [download] 100% of 11.90MiB in 01:07 [ffmpeg] Correcting container in "Como fazer um bom churrasco de Picanha-8BuQCD8eh9k.m4a" Post-process file Como fazer um bom churrasco de Picanha-8BuQCD8eh9k.m4a exists, skipping

To see the many options available in youtube-dl:

$ man youtube-dl

or:

$ youtube-dl --help

Have fun!

Filed under Audio, Linux, Video Tagged with audio, Linux, video, YouTube

Not able to access the CUPS Printer Manager in Firefox when, or after, using a proxy server

February 16, 2015 Leave a comment

Just a quick tip if you are trying to use the CUPS Printer Manager in a Firefox browser window (http://localhost:631/) to add a printer, manage a printer or view print jobs but the brower displays a message such as ‘Connecting to 10.48.80.49…’ and eventually times out and displays the following message:

Network Error (tcp_error)

A communication error occurred: “Operation timed out”
The Web Server may be down, too busy, or experiencing other problems preventing it from responding to requests. You may wish to try again at a later time.

For assistance, contact your network support team.

or the following message:

Unable to connect

Firefox can’t establish a connection to the server at 10.48.80.49.

    The site could be temporarily unavailable or too busy. Try again in a few moments.
    If you are unable to load any pages, check your computer’s network connection.
    If your computer or network is protected by a firewall or proxy, make sure that Firefox is permitted to access the Web.

    Try Again

This sometimes happens to me when my laptop is connected to a corporate network and the browser is, or recently was, configured to use a proxy server. Anyway, in Firefox I select ‘Open menu’ > ‘Preferences’ > ‘Network’ > ‘Settings…’ and make sure ‘No proxy’ is selected, then I select ‘Open menu’ > ‘Preferences’ and click on the ‘Clear Now’ button for ‘Cached Web Content’ (I have to click twice to clear the cache, for some reason) and the ‘Clear Now’ button for ‘Offline Web Content and User Data’. After doing this, I can access all the CUPS Printer Manager pages in the browser again.

Filed under Hardware, Internet, Linux, Networks Tagged with browser, CUPS, Linux, networks

NetworkManager creates a new connection ‘eth0’ that does not work

February 15, 2015 2 Comments

Several months ago a new entry ‘eth0’ began appearing under ‘Available connections‘ in the KDE plasma-nm widget (the KDE GUI front-end to NetworkManager) in my Gentoo Linux installation. However, there was already an automatically-created entry ‘Wired connection 1’ for the wired interface. In the plasma-nm GUI I could see that both entries were for the same interface (eth0) and MAC address. My laptop could access the Internet via the connection ‘Wired connection 1’ as usual, but not via the new connection ‘eth0’. And if I deleted ‘eth0’ in the plasma-nm GUI, ‘Wired connection 1’ could not access the Internet until I recreated ‘eth0’ manually.

Apart from the fact that two entries for the same interface is unnecessary, it was annoying because sometimes ‘eth0’ automatically became the active connection instead of ‘Wired connection 1’, despite the fact that only ‘Wired connection 1’ had ‘Automatically connect to this network when it is available’ ticked in the plasma-nm GUI. When this happened, the network icon on the Panel showed an active connection but in fact the laptop could not connect to the Internet. However, the connection did work as expected on the occasions when ‘Wired connection 1’ automatically became the active connection or if I switched manually to ‘Wired connection 1’ via the plasma-nm GUI.

Even more strangely, if I happened to be using WiFi when no Ethernet cable was connected, very occasionally the network icon on the Panel would change from a wireless icon to a wired icon and connection to the Internet would be lost. I would then have to re-select the wireless network in order to reconnect to the Internet.

As my laptop has only one Ethernet port, and as there was previously no ‘eth0’ entry under ‘Available connections‘, initially I thought that the new entry occurred because I had recently installed a new version of udev. I have the parameter net.ifnames=0 in the kernel boot line to stop udev/eudev using the so-called Predictable Network Interface Names, and I have the following udev/eudev rules files relating to networking:

# ls -la /etc/udev/rules.d/*net* lrwxrwxrwx 1 root root 9 Nov 30 15:25 80-net-setup-link.rules -> /dev/null # ls -la /lib64/udev/rules.d/*net* -rw-r--r-- 1 root root 452 Nov 7 09:57 /lib64/udev/rules.d/75-net-description.rules -rw-r--r-- 1 root root 1734 Jan 28 18:29 /lib64/udev/rules.d/77-mm-huawei-net-port-types.rules -rw-r--r-- 1 root root 491 Nov 7 09:57 /lib64/udev/rules.d/80-net-name-slot.rules -rw-r--r-- 1 root root 280 Jan 24 00:41 /lib64/udev/rules.d/90-network.rules

Perhaps udev (well, eudev, as I switched to using eudev after the problem started) did have something to do with the new entry, but I began to suspect that NetworkManager was the culprit. I think the problem first occurred after installing NetworkManager 0.9.10.0 last October, but it remained after I installed NetworkManager 1.0.0, until today when I made the various changes described further on.

I had merged NetworkManager 1.0.0 and preceding versions since 0.9.8.8 with USE flags -dhclient and dhcpcd, i.e. NetworkManager in my installation uses the DHCP client dhcpcd instead of dhclient. (I used to merge NetworkManager to use dhclient but found it did not work with 0.9.8.8 and later versions of NetworkManager.)

The relevant network services running in my installation are as follows, and nothing looks incorrect to me:

NetworkManager itself launches the DHCP client, so the installation should not be configured to launch a DHCP client. Indeed the output above shows that no DHCP client service is configured to run independently of NetworkManager, and I also double-checked that multiple instances of a DHCP client are not running (they’re not):

# ps -C NetworkManager PID TTY TIME CMD 6481 ? 00:00:22 NetworkManager # ps -C dhcpcd PID TTY TIME CMD 10378 ? 00:00:00 dhcpcd # ps -C dhclient PID TTY TIME CMD #

As far as WiFi is concerned, NetworkManager itself launches wpa_supplicant, so the installation should not be configured to launch wpa_supplicant. Indeed the output from rc-update and rc-status above shows that no wpa_supplicant service is configured to run independently of NetworkManager, and I also double-checked that multiple instances of wpa_supplicant are not running (they’re not):

# ps -C wpa_supplicant PID TTY TIME CMD 6491 ? 00:00:00 wpa_supplicant #

So, as far as I could tell, there was nothing wrong with the non-NetworkManager side of my installation.

I thought the problem might be due to the settings in the file /etc/NetworkManager/NetworkManager.conf, which contained the following:

[main]
plugins=keyfile
dhcp=dhcpcd

[ifnet]
managed=true
auto_refresh=false

[keyfile]
hostname=meshedgedx

I studied the manual pages for NetworkManager.conf:

# man NetworkManager.conf

If I understand correctly, the ifnet plug-in is Gentoo-specific (see References 3, 4 and 5 further on). The entries under [ifnet] in my NetworkManager.conf file were redundant in any case because the ifnet plug-in was not included in the plugins list under [main], so I deleted the entire [ifnet] section. There is no mention of the ifnet plug-in on the NetworkManager.conf manual page or in the Gentoo Linux Wiki article on NetworkManager, and a cursory look in the Gentoo ebuild for NetworkManager 1.0.0 clearly indicates the ifnet plug-in is broken. See, for example, the following comment in the ebuild:

# ifnet plugin always disabled until someone volunteers to actively
# maintain and fix it

and the following warning messages in the ebuild if the user has included ifnet in plugin=<plugin list> in NetworkManager.conf:

ewarn "Ifnet plugin is now disabled because of it being unattended"
ewarn "and unmaintained for a long time, leading to some unfixed bugs"
ewarn "and new problems appearing. We will now use upstream 'keyfile'"
ewarn "plugin."
ewarn "Because of this, you will likely need to reconfigure some of"
ewarn "your networks. To do this you can rely on Gnome control center,"
ewarn "nm-connection-editor or nmtui tools for example once updated"
ewarn "NetworkManager version is installed."

ewarn "You seem to use 'ifnet' plugin in ${EROOT}etc/NetworkManager/NetworkManager.conf"
ewarn "Since it won't be used, you will need to stop setting ifnet plugin there."

I modified NetworkManager.conf to contain the following:

[main]
plugins=keyfile
dhcp=dhcpcd
no-auto-default=eth0

[keyfile]
hostname=meshedgedx

Note that the ifnet plug-in was not specified in the plugins list in the [main] section of my previous NetworkManager.conf so it was not the cause of my problem, but I hoped that adding no-auto-default=eth0 to NetworkManager.conf would solve the problem. I deleted the ‘Wired connection 1’ entry from the plasma-nm GUI, ticked ‘Automatically connect to this network when it is available’ for the ‘eth0’ entry and made sure that option was not ticked for any of the other entries under ‘Available connections‘, then rebooted. There was no longer an entry ‘Wired connection 1’ in the plasma-nm widget GUI, just an entry for ‘eth0’, and the installation connected automatically to the wired network and I could access the Internet, but did not reconnect to the wired network if I removed and reinserted the Ethernet cable when also connected to a wireless network. So I was not home and dry yet.

I have read on various Web sites that NetworkManager prefers wired connections over wireless connections. I assume this is because NetworkManager sets a higher metric for the wired connection.

I am on a work trip at the moment and cannot use a dynamic wired connection, only a static wired connection, but I can see that NetworkManager 1.0.0 does set a higher-priority metric for wired connections:

# # Now with both dynamic wireless and static wired: # ip route show default via 10.90.21.1 dev eth0 proto static metric 100 default via 10.96.0.1 dev wlan0 proto static metric 600 10.90.21.0/24 dev eth0 proto kernel scope link src 10.90.21.112 metric 100 10.96.0.0/16 dev wlan0 proto kernel scope link src 10.96.87.86 10.96.0.0/16 dev wlan0 proto kernel scope link src 10.96.87.86 metric 303 127.0.0.0/8 dev lo scope host 127.0.0.0/8 via 127.0.0.1 dev lo 192.0.2.1 via 10.96.0.1 dev wlan0 proto dhcp metric 600 #

10.90.21.1 is the IP address of the gateway for the wired connection, and 10.90.21.112 is the IP address of my laptop’s wired interface. The smaller the metric value, the higher the routing priority. Notice that the metric for the eth0 interface is 100 whereas the metric for the wlan0 interface is 600, so it does appear that NetworkManager favours a wired connection over a wireless connection when both are active.

After doing all the above, I came across Debian bug report no. 755202: network-manager: keeps creating and using new connection “eth0” that does not work which appears to be exactly what I was experiencing. Various people posted solutions that worked in their particular circumstances, so I am none the wiser. Gentoo user Keivan Moradi posted message no. 79 on that bug report, about a warning message he found in the NetworkManager log file regarding a file /etc/NetworkManager/system-connections/.keep_net-misc_networkmanager-0, and he then deleted the latter file. I found the same message in /var/log/messages:

# grep networkmanager /var/log/messages Feb 9 04:10:05 localhost NetworkManager[10355]: <warn> error in connection /etc/NetworkManager/system-connections/.keep_net-misc_networkmanager-0: invalid connection: connection.type: property is missing Feb 11 15:53:05 localhost NetworkManager[13143]: <warn> error in connection /etc/NetworkManager/system-connections/.keep_net-misc_networkmanager-0: invalid connection: connection.type: property is missing

The file /etc/NetworkManager/system-connections/.keep_net-misc_networkmanager-0 also existed in my installation, so I also deleted it. It was a zero-length file and I do not know if it had anything to do with my problem:

# ls -la /etc/NetworkManager/system-connections/.keep_net-misc_networkmanager-0 -rw------- 1 root root 0 Jan 20 00:09 /etc/NetworkManager/system-connections/.keep_net-misc_networkmanager-0 # rm /etc/NetworkManager/system-connections/.keep_net-misc_networkmanager-0 #

Anyway, the file /etc/NetworkManager/system-connections/.keep_net-misc_networkmanager-0 has not reappeared since I deleted it.

Keivan Moradi had ‘id=Wired‘ under [connection] in the file /etc/NetworkManager/system-connections/eth0, and he decided to change the name of the file from ‘eth0‘ to ‘Wired‘. However, in my case the file name and the id in the file /etc/NetworkManager/system-connections/eth0 are both ‘eth0‘:

# cat /etc/NetworkManager/system-connections/eth0 [ethernet] mac-address=70:5A:B6:3E:C1:8A mac-address-blacklist= [connection] id=eth0 uuid=cb3d5786-f947-44b8-92f7-8471fc94c568 type=ethernet permissions= secondaries= [ipv6] method=ignore dns-search= [ipv4] method=auto dns-search=

I had already deleted and recreated the connection ‘eth0’ in the plasma-nm GUI by the time I checked the contents of the directory /etc/NetworkManager/system-connections/ so I do not know if the original file name and id were the same. I had also already deleted the connection ‘Wired connection 1’ in the plasma-nm GUI by the time I checked the contents of the directory; presumably files for connections ‘Wired connection 1’ and ‘eth0’ both existed in /etc/NetworkManager/system-connections/ before then. I do not know why the zero-length file .keep_net-misc_networkmanager-0 was created, but no further files have appeared in the directory since I deleted the connection ‘Wired connection 1’ and the file .keep_net-misc_networkmanager-0.

Keivan Moradi was also previously using a buggy r8169 kernel module (Realtek Ethernet hardware) and switched to using the r8168 module, but I am using a Qualcomm Atheros AR8131 Gigabit Ethernet card and an Intel Corporation Ultimate N WiFi Link 5300 card, so that part of his problem cannot be a factor in my case.

Anyway, as I wrote earlier, I no longer have two connection entries for the wired interface, and NetworkManager no longer creates automatically a second connection entry for the wired interface. And now if I am already connected to a wireless network, NetworkManager connects/reconnects automatically to a wired network with the ‘Automatically connect’ option ticked. So it looks like my problem is completely solved, although I reserve judgement until I have been able to use the laptop in my home network (which has the same router for both wired and wireless connections, whereas the wired network and wireless network are separate networks in the office in which I am now working).

Conclusion

If you had the patience to read all the above, I am impressed! If you also understood it, I am doubly impressed!

To cut a long story short, if you are experiencing a similar problem to mine, I recommend you do the following:

Check that your network driver is reliable. You can search the Web to see if other users have experienced problems with the same driver you are using.
Make sure the contents of NetworkManager.conf are correct. Read the NetworkManager.conf man page and the GNOME Wiki page on NetworkManager settings to find out what options are available.
Delete all the files (i.e. including hidden files) in the directory /etc/NetworkManager/system-connections/ and recreate your connections via either the NetworkManager GUI (e.g. plasma-nm in KDE or nm-applet in GNOME) or NetworkManager TUI (nmtui).

References

UPDATE (March 10, 2015): Well, I was right to reserve judgement until I was able to use my laptop with my home network. I am now back at home and an Ethernet cable is plugged into my laptop’s RJ45 socket. Even with the changes I made, when I boot the laptop NetworkManager sometimes (but not always) has two connections named ‘eth0’, one of them the ‘Active connection’ (but not able to connect to the Internet) and the other an ‘Available connection’. In this situation the wired network icon on the Panel has a yellow question mark superimposed. If I delete the ‘eth0’ active connection and use the other ‘eth0’, the latter works as expected and I have no trouble connecting to the Internet. In Debian bug report no. 755202 (see the link further up) user Frederik Himpe added a comment on March 4, 2015 that he is also still experiencing this problem and “It looks like there is a race somewhere, causing the network interface to be brought up before Network Manager is started, and this prevents correct configuration by NM”. So the problem is still unresolved. Hmm … I wonder if udev does have something to do with it after all.

UPDATE (March 12, 2015): The problem persists. I disabled use of IPv6 in /etc/avahi/avahi-daemon.conf to see if the Avahi daemon has something to do with the problem, but that made no difference. Later I also disabled use of IPv4 in /etc/avahi/avahi-daemon.conf, but that made no difference either. So it looks like the Avahi daemon is not the culprit. Checking via the plasma-nm GUI I notice that the ‘rogue’ eth0 Active connection has IPv4 disabled and IPv6 Link-Local enabled. So why is NetworkManager creating a second eth0 connection just for IPv6 Link-Local? And why on Earth is NetworkManager creating any additional connection at all when NetworkManager.conf contains no-auto-default=eth0? Surely this must be a bug in NetworkManager 1.0.0?

UPDATE (March 17, 2015): I have been investigating the problem further: see my latest blog post for details.

Filed under Desktops & Window Managers, Gentoo Linux, Hardware, Internet, Linux, Networks, Sabayon Linux, Wired, Wireless Tagged with Ethernet, Gentoo Linux, GNOME, Internet, KDE, laptop, Linux, NetworkManager, networks, router, Sabayon Linux, wired, wireless

Preventing a DNS Leak and WebRTC Leak when using Tor in Linux

February 5, 2015 1 Comment

Background

I have added to my 2011 Tor post a note on how to avoid a DNS Leak and WebRTC Leak, but am repeating it here in a new post, along with a Bash script that can be used to toggle the relevant Firefox user preferences before and after using Firefox with Tor, which makes the process easier.

The original eleven steps I gave in my above-mentioned post will not prevent the so-called DNS Leak problem. If your Web browser is not configured correctly it will still use your ISP’s DNS servers instead of the DNS servers favoured by Tor, in which case your ISP will know which sites you are accessing. See What is a DNS leak? for details. Reference 1 at the end of this post is a link to an article about DNS leakage, and Reference 2 is a link to an article on the Tor Browser, a browser designed to help avoid DNS leakage.

Furthermore, now that WebRTC is incorporated in some browsers, a ‘WebRTC Leak‘ is also possible if you have not configured your browser correctly.

Using the Tor Browser

Instead of performing Steps 1 to 11 in my original Tor post, download the Tor Browser, unpack it (no installation is required) and use that browser. Reference 3 below is a link to the download page, and Reference 4 below is a link to the instructions on how to unpack the tarball and launch the browser.

If you want even more security, you could instead download the ISO for the Tails Linux distribution, burn a LiveDVD or LivePenDrive — see my post Help for Windows users: How to create a Linux LiveCD, LiveDVD or LivePenDrive from an ISO file if you don’t know how to do that — and launch the browser from a Live Environment.

Using Tor with Firefox

However, if you still want to use the method I gave in my original Tor post then you could try all the additional steps given below to stop DNS leakage and WebRTC leakage.

Use the OpenDNS servers instead of your ISP’s DNS servers. That will not help, though, if your ISP is using a Transparent DNS Proxy.
Make the following changes to the preferences in Firefox (enter about:config in the Firefox address bar):
```
Preference Name                       Status   Type     Value
network.dns.disableIPv6               default  boolean  false  Change to true
network.dns.disablePrefetch           default  boolean  false  Change to true
network.proxy.socks_remote_dns        default  boolean  false  Change to true
browser.safebrowsing.enabled          default  boolean  true   Change to false
browser.safebrowsing.malware.enabled  default  boolean  true   Change to false
media.peerconnection.enabled          default  boolean  true   Change to false
```
(When you have finished using Tor, set media.peerconnection.enabled back to true if you want to use WebRTC. If you also want Firefox to warn you of phishing Web sites and Web sites that download malware, also set browser.safebrowsing.enabled and browser.safebrowsing.enabled back to true after you have finished using Tor.)

You may be wondering why I disable IPv6 DNS requests. It is because some IPv6-capable DNS servers may return an IPv4 address when an IPv6 address is requested. I disable the two ‘safe browsing’ preferences because, if enabled, they cause Firefox to compare visited URLs against a remotely-stored blacklist or submit URLs to a third party to determine whether a site is legitimate, and I don’t want the possibility of Firefox contacting other sites outside Tor or trying to find an IP address for a URL. The PeerConnection preference relates to WebRTC, and I disable that to stop Firefox contacting STUN servers (see Reference 5 below).
Test if there is still leakage by visiting the DNS leak test Web site and clicking on the Standard test button, and visiting the IP/DNS Detect site.

Furthermore, do not forget to use a Private Browsing window in Firefox.

Automate the editing of Firefox user preferences

Using about:config to change the user preferences in Firefox is laborious, so I created a Bash script edit_firefox.sh to toggle the relevant user preferences:

#!/bin/bash
# Script to change Firefox user preferences rather than
# using about:config from within Firefox.
# Make sure you only run this script when Firefox is not running.
#
FILE="/home/fitzcarraldo/.mozilla/firefox/fm8q09x0.default/prefs.js"
#
#
STATE=$(grep media.peerconnection.enabled $FILE | cut -c 43- | cut -d')' -f1)
if ! grep -q media.peerconnection.enabled $FILE ; then
  echo 'user_pref("media.peerconnection.enabled", false);' >> $FILE
  echo 'Added media.peerconnection.enabled false (secure) to prefs.js'
elif [ $STATE = "true" ]; then
     sed -i s/^.*media.peerconnection.enabled.*$/'user_pref("media.peerconnection.enabled", false);'/ $FILE
     echo 'media.peerconnection.enabled changed to false (secure) in prefs.js'
  else
     sed -i s/^.*media.peerconnection.enabled.*$/'user_pref("media.peerconnection.enabled", true);'/ $FILE
     echo 'media.peerconnection.enabled changed to true (not secure) in prefs.js'
fi
#
STATE=$(grep browser.safebrowsing.malware.enabled $FILE | cut -c 51- | cut -d')' -f1)
if ! grep -q browser.safebrowsing.malware.enabled $FILE ; then
  echo 'user_pref("browser.safebrowsing.malware.enabled", false);' >> $FILE
  echo 'Added browser.safebrowsing.malware.enabled false (secure) to prefs.js'
elif [ $STATE = "true" ]; then
     sed -i s/^.*browser.safebrowsing.malware.enabled.*$/'user_pref("browser.safebrowsing.malware.enabled", false);'/ $FILE
     echo 'browser.safebrowsing.malware.enabled changed to false (secure) in prefs.js'
  else
     sed -i s/^.*browser.safebrowsing.malware.enabled.*$/'user_pref("browser.safebrowsing.malware.enabled", true);'/ $FILE
     echo 'browser.safebrowsing.malware.enabled changed to true (not secure) in prefs.js'
fi
#
STATE=$(grep browser.safebrowsing.enabled $FILE | cut -c 43- | cut -d')' -f1)
if ! grep -q browser.safebrowsing.enabled $FILE ; then
  echo 'user_pref("browser.safebrowsing.enabled", false);' >> $FILE
  echo 'Added browser.safebrowsing.enabled false (secure) to prefs.js'
elif [ $STATE = "true" ]; then
     sed -i s/^.*browser.safebrowsing.enabled.*$/'user_pref("browser.safebrowsing.enabled", false);'/ $FILE
     echo 'browser.safebrowsing.enabled changed to false (secure) in prefs.js'
  else
     sed -i s/^.*browser.safebrowsing.enabled.*$/'user_pref("browser.safebrowsing.enabled", true);'/ $FILE
     echo 'browser.safebrowsing.enabled changed to true (not secure) in prefs.js'
fi
#
STATE=$(grep network.proxy.socks_remote_dns $FILE | cut -c 45- | cut -d')' -f1)
if ! grep -q network.proxy.socks_remote_dns $FILE ; then
  echo 'user_pref("network.proxy.socks_remote_dns", true);' >> $FILE
  echo 'Added network.proxy.socks_remote_dns true (secure) to prefs.js'
elif [ $STATE = "true" ]; then
     sed -i s/^.*network.proxy.socks_remote_dns.*$/'user_pref("network.proxy.socks_remote_dns", false);'/ $FILE
     echo 'network.proxy.socks_remote_dns changed to false (not secure) in prefs.js'
  else
     sed -i s/^.*network.proxy.socks_remote_dns.*$/'user_pref("network.proxy.socks_remote_dns", true);'/ $FILE
     echo 'network.proxy.socks_remote_dns changed to true (secure) in prefs.js'
fi
#
STATE=$(grep network.dns.disablePrefetch $FILE | cut -c 42- | cut -d')' -f1)
if ! grep -q network.dns.disablePrefetch $FILE ; then
  echo 'user_pref("network.dns.disablePrefetch", true);' >> $FILE
  echo 'Added network.dns.disablePrefetch true (secure) to prefs.js'
elif [ $STATE = "true" ]; then
     sed -i s/^.*network.dns.disablePrefetch.*$/'user_pref("network.dns.disablePrefetch", false);'/ $FILE
     echo 'network.dns.disablePrefetch changed to false (not secure) in prefs.js'
  else
     sed -i s/^.*network.dns.disablePrefetch.*$/'user_pref("network.dns.disablePrefetch", true);'/ $FILE
     echo 'network.dns.disablePrefetch changed to true (secure) in prefs.js'
fi
#
STATE=$(grep network.dns.disableIPv6 $FILE | cut -c 38- | cut -d')' -f1)
if ! grep -q network.dns.disableIPv6 $FILE ; then
  echo 'user_pref("network.dns.disableIPv6", true);' >> $FILE
  echo 'Added network.dns.disableIPv6 true (secure) to prefs.js'
elif [ $STATE = "true" ]; then
     sed -i s/^.*network.dns.disableIPv6.*$/'user_pref("network.dns.disableIPv6", false);'/ $FILE
     echo 'network.dns.disableIPv6 changed to false (not secure) in prefs.js'
  else
     sed -i s/^.*network.dns.disableIPv6.*$/'user_pref("network.dns.disableIPv6", true);'/ $FILE
     echo 'network.dns.disableIPv6 changed to true (secure) in prefs.js'
fi

You will need to change the path to the Firefox prefs.js file in the sixth line of the script, to suit your installation. If you have the utility mlocate installed you can find the file easily by using the command:

$ locate prefs.js | grep firefox

You will also need to make the script executable:

$ chmod +x edit_firefox.sh

You can see below how the script works:

$ ./edit_firefox.sh media.peerconnection.enabled changed to false (secure) in prefs.js browser.safebrowsing.malware.enabled changed to false (secure) in prefs.js browser.safebrowsing.enabled changed to false (secure) in prefs.js network.proxy.socks_remote_dns changed to true (secure) in prefs.js network.dns.disablePrefetch changed to true (secure) in prefs.js network.dns.disableIPv6 changed to true (secure) in prefs.js $ ./edit_firefox.sh media.peerconnection.enabled changed to true (not secure) in prefs.js browser.safebrowsing.malware.enabled changed to true (not secure) in prefs.js browser.safebrowsing.enabled changed to true (not secure) in prefs.js network.proxy.socks_remote_dns changed to false (not secure) in prefs.js network.dns.disablePrefetch changed to false (not secure) in prefs.js network.dns.disableIPv6 changed to false (not secure) in prefs.js $

Procedure to use Tor

So, if I am not using the Tor Browser, in summary I do the following (refer to my 2011 Tor post for the details):

Launch Polipo from a Konsole window.
Launch Vidalia from a Konsole window.
Launch edit_firefox.sh to make sure the relevant user preferences are set securely.
Launch Firefox and change the network settings to enable use of Polipo and Vidalia.
Launch a Firefox Private Browsing window and close the original window.
Visit TorCheck at Xenobite.eu, What Is My IP Address?, DNS leak test and IP/DNS Detect to be sure I am using Tor and that there is no DNS leak or WebRTC leak.

The router provided by my ISP does not allow me to change its DNS server settings. Using the router’s Web browser interface I was able to view the IP addresses of the DNS servers the router uses (Whois Lookup is a good place to check to whom an IP address belongs), and they are indeed owned by the ISP. However, the leak test Web sites I mention above show me that there is no DNS leakage to the ISP’s DNS servers when I have performed all the steps above.

When I have finished using Tor, I do the following:

Exit Firefox.
Stop Tor from the Vidalia GUI, exit Vidalia and end the Konsole session.
Stop Polipo and end the Konsole session.
Launch edit_firefox.sh to set the relevant user preferences back to their original settings.
Launch Firefox and change the network settings back to the original settings.

References

1. Preventing Tor DNS Leaks
2. Tor new advice (February 2014)
3. Download Tor Browser
4. Linux Instructions for Tor Browser
5. New Browser Based Flaw Leaks VPN Users’ IP Addresses

Filed under Internet, Linux, Networks Tagged with browser, DNS, Firefox, Internet, Linux, networks, router, security, Tor, WebRTC

Samsung Galaxy Note 4

February 1, 2015 3 Comments

I owned a Samsung Galaxy Note II since October 2012 and had been very pleased with it, although recently I had been finding it a little slow when needing a fast response at work, and performance of the camera in low light could have been a bit better. The launch of the Galaxy Note 4 last October piqued my interest, and I finally succumbed to temptation and bought one last week. I have to say I am impressed with Clove Technology: I ordered the smartphone via the Internet at 00:02 on 22 January and it was delivered to my house on 23 January. I ordered the UK model (SM-N910F), and you can find the Samsung user manual for that model on the Samsung Support page.

The smartphone has so many features and options that you really need to study the manual and watch some tutorial videos in order to get the most out of it. If you don’t, you’ll be missing out on several extremely powerful tools. I spent some time trawling YouTube for tutorial videos; below I list the ones I found the most useful, in no particular order. Several of them cover mostly the same ground, but usually there is a tip in one that is not in another so it pays to watch them all eventually. In any case, repetition helps reinforce the learning process.

sakitech

50+ Tips and Tricks for Samsung Galaxy Note 4

Explore Gadgets

Galaxy Note 4 – Tips,Tricks & Hidden Features

Galaxy Note 4 – Hidden Features (You Might Not Know About)

Top 10 Best Apps for Galaxy Note 4

LuneTech

Samsung Galaxy Note 4 Tips and Tricks, and Other Hidden Features

Gizmo Journal

Galaxy Note 4 Hidden Gestures, Tips & Tricks You Don’t Know About #1

Samsung Galaxy Note 4 Hidden Software Features, Tips & Tricks #2

Pocketnow