PRTG

    #############################################
    #  PRTG Network Monitor License Workaround
    #  Tested on version 12.4.6.3341
    #  Running on Windows Server 2008 R2 SP1
    #
    #  Published by ZMITGroup
    #############################################

    This workaround is quite easy, due to the lack
    of quality checks it's easy to keep evaluating.

    - Step 1: Edit C:\Windows\System32\drivers\etc\hosts file
    Add the following lines into your hosts file:

    ######- BEGIN
    # Disable activation checks , all HTTPS
    127.0.0.1          activation1.paessler.com
    127.0.0.1          activation2.paessler.com
    127.0.0.1          activation3.paessler.com
    127.0.0.1          activation1.paessler.ag
    127.0.0.1          activation1.paessler.eu
    # If you want to disable (auto) updates, remove comment char:
    # 127.0.0.1          autoupdate.paessler.com     # HTTPS
    # 127.0.0.1          updatecheck.paessler.com    # HTTP
    # 127.0.0.1          download.paessler.com       # HTTP
    # 127.0.0.1          download-cdn.paessler.com   # HTTP
    ######- END

    Now we did not check in whether how far it is needed to
    block these connections, but it's better to be on the safe side.

    After updating the HOSTS file, open CMD and type:
    ipconfig /flushdns
    And ping one or all domains to check if it's successful, if not, reboot.

    - Step 2: Get a lot of trial licenses
    This part is actually quite easy. Even though Paessler requires
    that you fill in an e-mail address, at time of publishing this
    workaround (22-01-2013) the validity is not checked and your
    trial key will be shown after clicking the submit button.

    Go to http://www.paessler.com/prtg/trial , and may we suggest to use a proxy?
    In case you did patch your hosts file, feel free to use any of the keys
    found at pastebin.com/GVWqYN9L .

    Each key will enable your PRTG Network Monitor system to run for 30 days.

    - Step 3: Changing / Setting your key
    Through RDP or hands-on, open up PRTG Server Administrator (EXE).
    Go to License and fill License Name and License Key, click "Check Key".
    After you've pressed the button, it should say the following:
    "PRTG Network Monitor Trial (30 days left)", now this number will count down,
    which should be quite obvious for a system administrator.

    Click OK, click YES to restart your probe (this shouldn't take too long).

    ---- You're all done! =)

    Every 30 days you will be required to fill in a new key, so make sure
    you have enough keys laying around for you to use, and to keep track of time!
    We personally aren't entirely sure if this is legal, however as it is a trial
    and you do not crack the program (except for blocking it in your "firewall"),
    it should in our eyes not be legal. This does however differ from country to country.


    ---- Extra information you might want / need / require / like to have?
    - Why wouldn't I just use a crack?
    Oh, you found one did you? Congratulations and go use it.
    At the time of publishing this, there wasn't a working crack out there.
    This is solely meant to work around this problem until there is one.

    - Unable to save HOSTS file due to permission problems:
    Simply open up notepad or any other text editor as ADMINISTRATOR, when
    the program is launched open the file from within the application.

    - I want to fake the ACTIVATION OK result, what path is it located at?
    activation1.paessler.com/apps/activation/prtg9.php

    - For some reason my hosts file does not block the check
    That's a pitty, there are lots of programs out there that'll still do this
    for you. Another way to go is to have your own DNS server on which you'll
    put the records shown in step 1.

    - Can I update PRTG Network Monitor while using this?
    If you haven't blocked any of the update links, possibly yes.
    Keep in mind that newer versions might have a better check build in,
    if you don't NEED to update, please don't for the sake of safety.

    - What happens when I forget to update my key?
    After 30 days, if HOSTS patch is applied, you should have a 10 day
    license GRACE period, we however did not investigate whether or not
    this is 10 days after each month or whether it deducts itself.

    Small example:
    1st time GRACE: use 2 days
    2nd time GRACE: Do we have 8 or 10 days of GRACE period?
    We did not check that.

    - Why not simply release a crack?
    To say it straight-forward: not (entirely) legal.

    - I want to contact you, is that possible?
    Simply put? no.

    - I found an error in this document
    That's simply put very possible, you can probably fix it yourself,
    this isn't rocket science, or Particle Physics for that matter.