Autodesk Pixlr online image editor

Nearly perfect online image editor Autodesk Pixlr . For those cases when you don’t have any software installed to do the task.


Hikvision NVR DS-7608NI-E2

Hikvision security cameras are good, but NVRs can really drive you mad before you get them working.

Few notes on setting up DS-7608NI-E2 with Hikvision IP cameras.

Problem 1)

What: As soon as you switch the unit on, it starts beeping. Beeps come in series and constantly keep repeating. There is nothing about it in the manual.

Why: The unit has detected that it either does not have a HDD installed, or that HDD is not formatted (initialised).

How: Ignore the beeps, go to system menu, find the section about the disk management ant initialise the disk. As soon as you start formatting, the annoying beeps will stop.

Problem 2)

What: You easily set up continuous recording, but you can’t set up motion detection. Obviously the Hikvision NVR fails to detect motion. You check and re-check the settings, everything seems to be correct, but motion detection just does not work.

Why: The unit needs administrator password for the cameras. It is not obvious in the Web interface, though is clear enough in the console GUI (direct connection to display/screen).

How: Provide the administrator credentials. I suggest changing the admin passwords for cameras to numbers only, as I suspect that letters in the password confuse the NVR .

You can see that after you change motion detection settings in the NVR, they change accordingly in the IP camera itself too. The NVR is giving orders to cameras and that’s why it needs the admin password.

Problem 3)

What: It is quite likely that, while you struggle with IP camera login credentials, you will experience a situation where not only the NVR fails to connect to the cameras, but you also loose ability to login into the cameras via web interface and keep getting cryptic message “Network abnormal”.

Why: Not really clear, but it seems that the NVR confuses cameras by constantly trying to log in with incorrect credentials.

How: Just power off the respective camera by pulling the plug and then switch it on back again. It should be working now. You may still need to reconfigure or shut down the NVR before you are doing that, so that it does not mess it all up again before you even get back to your browser.

Sequentially number files

  • Number all PDF files in the directory (rename them like 001, 002, 003 … ) in bash:
a=1; for i in *.pdf; do new=$(printf "%03d.pdf" "$a"); mv -- "$i" "$new"; let a=a+1; done

Get Windows XP network information on command line

To display or set Windows XP network parameters (IP address, default gateway, DNS servers used, routing etc.) from the command line use netsh utility.

To see the list of options type:

  • netsh /?

Tunnelblick: access locally

You set up openVPN on Mac OS X with tunnelblick. You attempt to connect but get a message This file server is available on your computer. Access the volumes and files locally.

The problem may exist between the keyboard and the chair. Check if you are not connecting  to your own IP address instead of the server’s address.


That awkward moment when you buy an Apple Mac computer just to realize that Yosemite Mac OS X sucks in comparison to the Linux Mint Mate you used before.

Disable attachments in Postfix

You have postfix mail system and you want to make it reject, delete or rename potentially dangerous attachments. NB: Before you start it is advised to make a backup copy of directory /etc/postfix/ .

1) Solution One

Quite simple one, without any extra installs.

  • Edit /etc/postfix/ At the end add single line:

mime_header_checks = regexp:/etc/postfix/mime_header_checks

  • Edit /etc/postfix/mime_header_checks. Create the file if it does not exist. At the end add single line:

/name=[^>]*\.(lnk|dll|shs|vbe|hta|com|vbs|js|jse|bat|cmd|vxd|scr|shm|pif|chm|zip|exe)/ REDIRECT

This will redirect all incoming mail with the listed files to the indicated mail. You can also just reject such mails by writing REJECT instead of REDIRECT, followed by an optional  text message.

  • Reload the new postfix configuration:

postfix reload

2) Solution Two

A bit more sophisticated.

  • Install renattach.

sudo apt-get install renattach

  • Create user ‘filter’. It is recommended that it does not have neither password, nor home directory, nor login shell.

adduser –disabled-login –no-create-home –shell /bin/false filter

  • Edit /etc/postfix/ At the end add two lines:

filter unix – n n – – pipe flags=q user=filter argv=/usr/bin/renattach -l -p /usr/sbin/sendmail -i -f ${sender} — ${recipient} NB:

  1. The second line shall start with two spaces.
  2. Write full program names or you may get error with message “temporary failure. Command output: Error executing pipe command: sendmail “)
  • Edit again /etc/postfix/ Find at the top of the file the section which looks like:

# ========================================================================== # service type private unpriv chroot wakeup maxproc command + args # (yes) (yes) (yes) (never) (100) # ==========================================================================

smtp inet n – – – – smtpd

And add this line under it:

-o content_filter=filter NB:

  1. The line shall start with four spaces.

If there are already some other options, you may add it under them all, e.g.:

smtp inet n – – – – smtpd
-o content_filter=spamfilter
-o receive_override_options=no_address_mappings
-o content_filter=filter

  • Edit configuration file /etc/renattach/renattach.conf:

Go to the bottom of the file and uncomment badlist lines. You can add extra your own lines if you want, e.g.

badlist = ZIP

Also, change the message in the subject of the processed message, e.g.:

add_subject = [Suspicious attachments renamed]

Or invent your own extension for the renamed files, e.g.:

new_extension = suspicious

  • Reload the new postfix configuration:

postfix reload

Enjoy extra protection!

Both Solutions as they are described here do not work together, because the Solution One will be first to get to the mail and it will never make it to the renattach. So you have to choose either one of them.


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