blog.plee.me About software, technology and random things

18Jan/170

PhonerLite With FRITZ!Box

Hello!

If you want to set up your PhonerLite VoIP/SIP client with the FRITZ!Box so you can receive phone calls on your computer as well, of course you should have a look at the official AVM documentation (like the one for the FRITZ!Box 7390).

However, I encountered the following problems:

  • outgoing calls would result in a "480 Temporarily Unavailable" error (even the test number **797)
  • saving the configuration (tab "Configuration" => "Save" button) repeatedly would cause the status bar to alternate between
    • showing a red indicator and the error message "sip:<number>@fritz.box not registered <Connectivity Checks Failed>" every second click
    • showing a green indicator and the message "sip:<number>@fritz.box registered" every other click

I changed the following server / connection settings to fix the problem:

  • Proxy/Registrar: <FRITZ!Box IP address instead of fritz.box, e.g. 192.168.1.1>
  • Domain/Realm: fritz.box

After that, every time I saved the configuration if would show the success indicator and message and telephony just worked in general.

My local network interface uses an external DNS server for hostname resolution and I have added the fritz.box name manually in my hosts file. This might be why this was causing me problems.

I hope this was of any help to you in case you encountered this as well.

Thanks for reading!

17Dec/160

Installing mod_cloudflare For Apache HTTPd 2.4 On Debian 8 (Jessie) Via Aptitude Repository

Hi!

If you are using the Cloudflare proxy functionality, you will find that your web server will end up only working with Cloudflare's IPs instead of the visitors'. After quite some time I thought that there has to be a better way to go about this, and I found mod_cloudflare, a solution officially developed by Cloudflare themselves.

When I was looking at the official Cloudflare documentation on how to install mod_cloudflare for Apache 2.4 on Debian 8 (Jessie) today, I was disappointed to find that they were only recommending manual ways: installing a .deb package or compiling the module yourself.

Luckily I found a guide on how to accomplish the installation with the standard apt-get / aptitude tool for Debian / Ubuntu.

This is how:

  1. Add the aptitude repository to a new sources list file, e.g. at /etc/apt/sources.list.d/cloudflare-main.list - with this content:
    deb http://pkg.cloudflare.com/ jessie main
  2. Download the Cloudflare repository key and add it to the aptitude known keys:
    # wget https://pkg.cloudflare.com/pubkey.gpg
    # apt-key add pubkey.gpg
    # rm pubkey.gpg
  3. Update the aptitude cache:
    # aptitude update
  4. Look at which packages are available in the new repository:
    # grep ^Package: /var/lib/apt/lists/pkg.cloudflare.com_dists_jessie_main_binary-amd64_Packages
  5. Install mod_cloudflare:
    # aptitude install libapache2-mod-cloudflare
  6. Restart the Apache HTTPd service:
    # service apache2 restart

Hopefully this way of installing will enable everyone to update / maintain it much more easily and with less one-time use packages installed.

Additionally, this could prove even more useful for people who want to install more Cloudflare packages.

I am confident that this method also works for Ubuntu and other versions of Debian - just replace the "jessie" part in the aptitude sources list file with your distribution major release codename (like "wheezy" for Debian 7 or "vivid" for Ubuntu 15.04).

Thanks for reading!

Original source: https://emtunc.org/blog/01/2016/installing-mod_cloudflare-ubuntu-14-04-apache-server/

7Jun/150

Memory Leaks / Problems with Long-Running Symfony / Doctrine Console Applications

Hi!

I recently built several console applications that have to keep running as daemons as part of a more complex website. As soon as I added Doctrine for its highly comfortable ORM functionality, I noticed a significant increase in the applications' memory usage, which made sense because it would load Doctrine's code in order to use it. The worst part of it, however, was that the processes kept eating up more and more memory the longer they ran and with each Doctrine query they executed. Finally the processes ended up being killed by Linux's OOM Killer due to the high amount of memory that they wanted allocated for them.

Clearing the Doctrine Entity Manager ($entityManager->clear()) and triggering PHP's garbage collection manually did not help at all. So I assumed it had something to do with the data that Doctrine accumulates in the background.

During my research I finally stumbled upon this Stack Overflow question: Memory leaks Symfony2 Doctrine2 / exceed memory limit

Apparently, Doctrine uses an SQL Logger to log each and every query it uses when running in debug mode.

Due to the nature of Symfony console applications starting up in the dev environment by default when launching them from the command line, it also kept enabling the debug mode. That in turn enabled the SQL Logger which gathered more and more data and kept it in memory.

I decided to launch the processes by simply manually disabling the debug flag. Using the dev environment is not a problem for me, so I just did the following:

$ php app/console custom:command --no-debug

You could also set the environment variable SYMFONY_DEBUG to 0 before launching the command without the --no-debug flag, as it also respects its value - refer to app/console's source code.

Alternatively, you could start it in a non-dev environment:

$ php app/console custom:command --env=prod

or

$ php app/console custom:command -e prod

or just set the environment variable SYMFONY_ENV before launching it.

This way, the SQL Logger is not enabled.

My processes have been running at stable memory usage size ever since.

Another way would be to deactivate the SQL Logger in the code by principle, but that would be defeating the purpose of the nice built-in features of enabling/disabling the debugging mode, so I rather chose the first path. It might come in handy sooner or later after all, and reverting those changes just to re-enable the SQL Logger would be an unnecessary pain.

I hope this was helpful to you. It certainly took me some time to get behind it.

23Nov/140

Using msysgit With PuTTY Pageant & Plink

Hi!

If you have installed msysgit and are planning on using it in combination with Pageant from the PuTTY tool suite, you might run into the problem that it does not attempt to use any of the keys you have already loaded into Pageant. You can fix this by telling msysgit which program to use for the git fetch and pull operations:

  • Open your System window (Windows + Pause or "Start" => Right-click on "Computer" => "Properties")
  • Click on "Advanced system settings" (on the left)
  • Click on "Environment Variables..." (on the bottom)
  • Add a new system variable (or user variable if you just want this setting for the current user): "New..."
  • Variable name: GIT_SSH
    Variable value: (path to plink.exe) for example: C:\Program Files (x86)\PuTTY\plink.exe (important: just the path, no quotation marks at the beginning or the end!)
  • If you haven't already on this system / user, connect to the server via PuTTY in order to get the SSH server fingerprint prompt and remember it
  • Close any existing Git Bash / msysgit instances and start it up again

This should do it!

I hope this was helpful.

Thanks for reading!

Source: http://www.bitsandpix.com/entry/git-setup-msysgit-install-with-pageantplink-from-putty/

16Nov/140

Mozilla Thunderbird: Changing the EHLO / HELO Value in the “Received”-Header for Outgoing Mail

Hi!

If you have had a look at your outgoing e-mail headers that you've sent from Mozilla Thunderbird, you might have noticed that Thunderbird uses the IP of the network interface that it uses to connect to the internet with by default. If you are using a router on your network, this is a private IP from your LAN (for example 192.168.1.2) instead of one that might be of actual use.

Example:

Received: from external.sender.host.example.org ([123.123.123.123] helo=[192.168.1.2]) by
 mail.example2.org (incoming-mta-service) with esmtpsa (outgoing-mta-service) id
 0a1b2c-3D4e5F6G7h-0a1B2c for <[email protected]>; Sun, 02 Nov 2014 20:55:41 +0100

where "123.123.123.123" is the publicly facing IP and "external.sender.host.example.org" is its hostname.

If you do not wish to expose this information to every and all recipients of the e-mails you are sending with Thunderbird to (maybe out of security concerns in a business environment), you can set the EHLO / HELO value manually for every outgoing e-mail sent by the Thunderbird client with your current user profile and even for every simple SMTP server individually.

Here's how:

Globally

  • Open your Thunderbird options ("Tools" => "Options")
  • "Advanced" => "Config Editor..."
  • Create (or edit) the entry named "mail.smtpserver.default.hello_argument". If you need to create it, use right-click => "New" => "String".
  • Change the value to the desired IP or hostname (FQDN).

Per SMTP server

  • Open your Thunderbird options ("Tools" => "Options")
  • "Advanced" => "Config Editor..."
  • Create (or edit) the entry named "mail.smtpserver.smtp<number>.hello_argument" where <number> is the ID for the SMTP server you would like to apply the setting to. Type "mail.smtpserver.smtp" to see which ones are available and which ID they have. If you need to create the entry, use right-click => "New" => "String".
  • Change the value to the desired IP or hostname (FQDN).

Technically this value is not relevant for sending/receiving the mail, but because it might be used for spam scoring or simply out of courtesy I would recommend entering a valid IP / hostname.

I myself am using 127.0.0.1.

Thanks for reading!

Sources:

9Nov/140

Deleting Huge Directories in Windows Via Command Prompt

Hi!

If you'd like to delete a huge folder / directory in Windows with maybe thousands or hundreds of thousands of files inside, doing that via Explorer might cost you a lot more time than via command prompt.

Here's how to do it faster:

  1. Open the command prompt by using "Start" => "cmd" and navigating to the desired path via "cd <path>" or "pushd <path>"
    - OR -
    navigate to the folder in the Explorer and use Shift + right-click and "Open command window here"
    (Note: if deleting the desired folder requires elevated privileges, you will have to start a command prompt in elevated mode and navigate the old-fashioned way)
  2. Use the following command:
    rmdir /s /q folder

A little explanation about rmdir's flags:

  • /s: removes the directory itself including all the contained files and subdirectories
  • /q: forces deletion and does not ask for approval

Doing this can be very helpful in a coding environment where you can easily end up with thousands of small files.

Thanks for reading!

Source: https://stackoverflow.com/questions/186737/whats-the-fastest-way-to-delete-a-large-folder-in-windows

2Nov/140

Viewing Hidden Devices in Windows Device Manager

Hi!

If you are trying to find a device that has been hidden in your Windows Device Manager, for example because you don't have it plugged in at the moment, you might find this little guide handy.

  1. Open the command prompt ("Start" => "cmd")
  2. Enter
    set devmgr_show_nonpresent_devices=1
  3. Then start the Device Manager from the command prompt via
    devmgmt.msc
  4. In the Device Manager, click "View" => "Show hidden devices"

I hope this helped 🙂

Thanks for reading!

Source: https://support.microsoft.com/kb/241257

1Dec/1333

Installing the Logitech F710 Wireless Gamepad on Windows 7 x64 (XInput Driver)

Update from 2015-10-18: Windows 10 Pro (x64) does not appear to require this workaround. It automatically installed the correct driver and allowed me to use the controller right away.

Hi!

In order to be able to benefit from using the XInput mode for the Logitech F710 Wireless Gamepad, of course you need to install the correct driver. This is made a little hard for Windows 7 x64 seeing as there is no driver that comes with the device itself.

I found a guide on how you can manage it by using Microsoft's official Xbox 360 Controller driver.

Be careful though, you're messing with driver files. Use this guide at your own risk.

  1. Go to the Microsoft Hardware downloads page: http://www.microsoft.com/hardware/en-us/downloads
  2. Click on the category "Gaming"
  3. Click on the link "Xbox 360 Wireless Controller for Windows"
  4. Download the correct version of the file (Windows 7 64-bit only) and install it
  5. Open the Device Manager (e.g. [Windows]+[Break] => Device Manager)
  6. Right-click on the entry with "Logitech F710" in its name and the yellow triangle icon in front of it
  7. Open its properties
  8. Switch to the "Details" tab
  9. Choose the property "Hardware Ids"
  10. Right-click on the one without the "&REV_<Number>" at the end of the name and copy it. It should look something like this: USB\VID_046D&PID_C21F
  11. Go to the directory in which you installed the Xbox 360 Accessories Software a minute ago: C:\Program Files\Microsoft Xbox 360 Accessories
  12. Open the file Xusb21.inf with a plain text editor like Notepad
  13. At the top in the commented section you can see the line containing "Wireless Common Controller USB\Vid_045E&Pid_0719". Search for "USB\Vid_045E&Pid_0719" and replace each occurence with the hardware ID you copied earlier. Afterwards, save it to the file. You might need to have your editor program in elevated privilege mode in order to do so.
  14. Go back to the Device Manager with the open F710 properties window
  15. Switch to the "Driver" tab
  16. Click on the "Update Driver..." button
  17. In the assistant, choose "Browse my computer for driver software"
  18. Choose the path "C:\Program Files\Microsoft Xbox 360 Accessories"
  19. Confirm the driver warning and you're good to go

To check if it really worked, you can just press the Logitech button on the game controller and it should cause a little frame with the Xbox logo, the text "Click for Help" and a down-pointing arrow button and an X button to pop up in the lower center of your screen.

I do not usually recommend modifying driver files like that, but I have used this method before and it worked for me, so I stopped looking for a better way, as there doesn't seem to be any official solution provided by Logitech themselves (which is a shame).

Original post and the ones who can be credited with this solution: post by breakfastmonkey on the official Logitech forums (referencing a couple of previous posts in the same thread).

Thanks for reading.

2Jul/130

Access Control via Hybrid .htaccess for Both Apache HTTPd 2.2 and 2.4

Hi!

If you're running the Apache HTTPd in the versions 2.2 and 2.4 in different environments but would like to control access to certain directories (include, lib, ...) via Apache, chances are that you don't want to use one 2.2 specific file and a different one for 2.4, especially if you keep transferring and synchronizing the files between those different setups.

Between versions 2.2 and 2.4 a couple of things have changed. The perhaps most prominent change would be the one that comes with the new mod_authz_host module and deals with authorization / access control. Instead of using Order, Allow, Deny and/or Satisfy you are now advised to use the new Require directive.

So what do you do if you cannot switch every .htaccess over to the new format for reasons like the one mentioned in the beginning?

You could in fact enable the mod_access_compat module and keep rolling with the old configuration. But that would only mean procrastinating until you would finally have to deal with it anyway.

The better solution is to use configurations that are not even necessarily dependent on your Apache version (remember, you could just load the legacy compatibility module in 2.4), but in fact check for the correct module to work with. The key element to work with here is the IfModule directive.

# Apache 2.4
<IfModule mod_authz_core.c>
    Require all denied
</IfModule>

# Apache 2.2
<IfModule !mod_authz_core.c>
    Order Allow,Deny
    Deny from all
</IfModule>

As you can see, there are two checks that basically work as an "if ... else" selection. The rest should be self-explanatory.

For more information about the new way of handling access with the Apache HTTPd 2.4, please refer to the official documentation.

I hope this was of any help to you.

Thanks for reading.

20May/121

Making Traceroutes Work with a Firewall (Windows)

Hi!

Even though I've had software firewalls in action for years now, I haven't really come across too many instances where I'd need traceroutes. The few times I did, however, I noticed that I only got output like the following:

>tracert example.com

Tracing route to example.com [123.123.123.123]
over a maximum of 30 hops:

  1     *        *        *     Request timed out.
  2     *        *        *     Request timed out.
  3     *        *        *     Request timed out.
  4     *        *        *     Request timed out.
  5     *        *        *     Request timed out.
  6     *        *        *     Request timed out.
  7     *        *        *     Request timed out.
  8     *        *        *     Request timed out.
  9     *        *        *     Request timed out.
 10     *        *        *     Request timed out.
 11    50 ms    50 ms    50 ms  example.com [123.123.123.123]

Trace complete.

The number of hops would of course vary for the specific host / IP address.

Today I had to use traceroute in order to analyze a couple of networking problems. That was the incentive I needed to look up why it didn't work.

The fact that not even my router was showing up was a big indicator that something was wrong with my local firewall settings.

After searching the web for a couple of minutes, I found out what I was looking for at this page: http://www.phildev.net/ipf/IPFques.html#ques34

Traceroute is using ICMP packets (plus UDP on Linux systems, but that's outside the scope of this blog entry. You can read more about it on the page I linked above). But even for an outgoing traceroute you need to accept incoming ICMP packets.

Which ones? These:

  • ICMP TTL Expired (Type 11, Code 0)
  • ICMP Port Unreachable (Type 3, Code 3)

Once you've enabled these types of packets for incoming traffic in your firewall(s), you'll see that your traceroute will now function as it should.

If your firewall does not allow you to configure accepting specific types of ICMP packets, try allowing incoming ICMP packets altogether (if that's not too much of a compromise for you).

Anyway, long-ish story short: It's working now 🙂

Thanks to the webmaster of the page I linked above! And thanks to you for reading.

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