Vasile's SpyApplet FAQ

1. What does VasSpyApplet ?
   It takes the main information from the visitor's computer and sends this information to the specified e-mail address. So, you can see the profile of your visitors, the geographical distribution ... It's especially usefull for people that are hosted by someone else and cannot access their server's stats.
   In fact, the applet is running "clientside", so you can avoid problems with server's folks. You have nothing to change on the server.
2. When VasSpyApplet will work from my page ?
   In order to work, the hosting web server must be in the same time a mail server (SMTP).
3. How to configure the applet ?
   Currently, you have five parameters to configure:
   • to - put here the e-mail address where you want to receive the mails, for example "vasile@club-internet.fr"
   • from - put here the e-mail address of the sender, for example "vasile@chez.com". It can be the same address as the addressee or another one, but must be yours. It means do not put my addresses or a fake one!
   • msg - put here the text you want the browser display in the StatusBar when the applet is already loaded. The browser will show "your_message" instead of "Running applet VasSpyApplet". It can be for example " ".
   • color - to change the background color of VasSpyApplet by putting the color you want (better to be the same as the HTML page's). The applet then will be invisible for the visitor. For example put "#FFFFFF" to obtain the white color or "#000000" for a black one.
   • subject - put here the subject of the e-mail you want to receive, for example "VasSpyApplet"
   Also, you can specify the name of the applet. So, the browser will show "Loading applet your_name_here" instead of "Loading applet VasSpyApplet". For example, you can put NAME="Vasile".
   The two other parameters (referrer and UserAgent) will be filled-in by JavaScript.
4. How to see if my webserver is a mailserver ?
   To see if your web server is also a mail server (SMTP), under the command prompt type (when you are connected, of course) :
   telnet your_web_server 25, for example
   telnet technopole.le-village.com 25 for my page.
   If you have no errors, and it connects to, then the webserver is a mail server (SMTP) too.
5. My webserver is also a mailserver, but it does not work !
   Some mailservers are configured in order to not send mails outside their domain. It's means that they do not relay mails to other mailboxes then their own. To see whether your mailserver relay or not, you have to try a complete SMTP session. For example :
   220 ESMTP Sendmail 8.8.5/8.8.5; Sun, 7 Sep 1997 22:17:10 -1000
HELO vasile.md
250 Hello vasile.md [194.158.108.66], pleased to meet you
MAIL FROM: vasile@club-internet.fr
250 vasile@club-internet.fr... Sender ok
RCPT TO: vasile@club-internet.fr
571 vasile@club-internet.fr... Mail relaying for ppp-108-66.villette.club-internet.fr denied.
   The replay can also be : 553 vasile@club-internet.fr... We do not support relaying
   Possible solutions : send the mails to a local address, ie to an address recognised by the SMTP server or use codebase tag.
6. How all this sending mail stuff works ?
   Nothing complicated here. This is a standard SMTP (Simple Mail Transfer Protocol) communication. Described in RFC (Request For Comments) number 821 at http://www.nexor.com/public/rfc/rfcs/rfc821.txt
   1. You say HELO "your_host"<CarriageReturn/LineFeed> to the server (in general, you can put whatever you want there)
   2. You say MAIL FROM: you@youserver.com<CR/LF>
   3. You say RCPT TO: the_person@you_contact.com<CR/LF>
   4. You say DATA<CR/LF>
   5. You put the body of the e-mail
   6. You type .<CR/LF> at the end of the message
   7. You say QUIT<CR/LF>
   Type HELP<CR/LF> if you have problems.
   SMTP command keywords are case insensitive.
7. Everything is OK, but why sometimes I don't receive mails ?
   This applet may not work if the visitor is behind a firewall, where some connections are restricted. Also, sometimes the security configuration of Internet Explorer 4 does not allow the applets to connect to remote hosts. In other cases, the mailserver is simply down (it happens). It will not work also if the visitor is using a very old browser (Netscape 1.0, MSIE 2.0 or lower), or if Java was disabled in the browser.
8. What to do if my webserver is not a mailserver ?
   You cannot then spy the visitors using a Java applet from your host. Of course, you can always ask the system administrator to fix this situation, but it'll be hard to persuade him.
   Or you can launch this applet from my web page (using codebase) like this:
   <SCRIPT LANGUAGE="JavaScript">
<!--
document.write("<APPLET CODEBASE=\"http://technopole.le-village.com/vasile\" CODE=VasSpyApplet.class WIDTH=5 HEIGHT=5 NAME=\"Vasile\">");
document.write("<PARAM NAME=from VALUE=\"vasile@chez.com\">");
document.write("<PARAM NAME=to VALUE=\"vasile@club-internet.fr\">");
document.write("<PARAM NAME=msg VALUE=\" \">");
document.write("<PARAM NAME=color VALUE=\"#B4B88C\">");
document.write("<PARAM NAME=subject VALUE=\"VasSpyApplet\">");
document.write("<PARAM NAME=browser VALUE=\"");
document.write(escape(navigator.userAgent));
document.write("\"><PARAM NAME=referrer VALUE=\"");
document.write(escape(document.referrer));
document.write("\"></APPLET>");
// -->
</SCRIPT>
9. Why do I get always this host/IP address : localhost/127.0.0.1 ?
   For security reasons, MSIExplorer always give this host/IP address (in order to avoid revealing IP addresses which are behind a firewall). However, you can get the real IP address. :-)
10. How to get the real IP address of the visitor ?
    In order to have the real IP address of the visitor, look at all the headers of the mails received from VasSpyApplet. If you use Netscape3 as mail client, make "Options/Show Headers/All". In Netscape4 it's "View/Headers/All". See this example.
11. Why do I get the wrong time ?
    It's a Netscape 4 bug. Netscape developers think California is the center of the universe, so they always give PST (GMT-9) time. :-)
12. Why it shows so few total/free memory ?
    In fact, it shows the state of Java Virtual Machine's memory, and not the computer's one.
13. It is possible to see the e-mail adress and the name of the visitor ?
    No it's impossible to do it in Java. This would be a terrible security problem.
    • A browser is not obliged to have an integrated e-mail client (for example, IExplorer3 hasn't). Even if the browser has one, not all the people configure and use this module.
    • What to do with their e-mails ? People in general don't like spam mails.
    • If the visitors want to be in contact with you, they'll contact you.
    • I get a lot mails from VasSpyApplet and it seems difficult for me to write every customer.
    So, please don't write me "I'll pay you big money if you find e-mail addresses of my visitors".
14. It is possible to find out the processor speed, the Ethernet card address, etc. ?
    No, it's impossible for an applet.
15. Why the applet does not show that I'm using Windows 98 ?
    Normal, because the OS itsself tells this. But if you have "OS=Windows 95, OS version=4.10", it means that it is Windows 98.
16. Can't you change it in order to specify the mailserver to use ?
    No. Applets can connect only to the host they were downloaded from. It is a security restriction imposed to applets, see Java Security FAQ for more details.
17. Can the information retrieved by your applet be stored in a file(datatbase) ?
    Yes, it could be done. But ONLY if you have access to the webserver, ie you can launch programms on it. But if you can do this, there are other options(CGI...), which can be more interesting than VasSpyApplet.
18. Why I got "unterminated string literal" ?
    You have to put all the text between quotes (") on a single line. Don't wrap lines.
19. Why does the counter on my page show a different number than VasSpyApplet ?
    Counters work very differently than VasSpyApplet because they are unable to track browsers, system information, referrers... In order that VasSpyApplet be able to send a mail to you, the applet must load completely on your page, start to execute, connect to the mailserver, collect and send the information. All these steps have to be done before your visitor leaves. There are some limitations due to visitor's configuration.
20. I made everything but it's still not working. What to do ?
    Verify if your webserver is a mailserver too. If not, use codebase tag. Configure the applet properly. Check if you are not behind a firewall (if you are trying from your company's network, it's almost sure you are behind a firewall). Check if you have a Java-enabled browser (Netscape 2.02 or above, MSIE 3.0 or above). It won't work if you are launching it from your hardisk ! Also, it won't work if you change the name of VasSpyApplet.class file. If it's still not working, contact the author (give as much details as you can).
    Don't forget that computers make never mistakes, there's always a human error. Even when creating buggy computers. :-)

• Take a look at the real IP address of the visitor.
• Take a look at his local time zone (the difference between the GMT time and the local one). Very often, under Windows 95, the date is something like : "Thu Aug 21 17:07:06 Bangkok Standard Time 1997". Very vivid, isn't it ?
• If you have only the numeric IP address of the visitor, you can perform a traceroute (tracert under win95) to his address. So, you'll see where he's located.
• For a better use, put the applet tag at the top of the HTML page. It will load the applet faster and will send the mail immediatly. If you place the applet at the bottom of your page, it will be the last thing to load, so there is a great chance that a visitor will click another link and leave the page before the mail is sent. This is especially the case when there are many graphics on your page.
• Don't put VasSpyApplet on all the pages of your site. It will just overwhelm your mailserver and bring redundant information.
• (For Java programmers) The best way to make the applet working is to take the source code and recompile it with "hard-coded" values. In fact, sometimes the browser pass incorrectly the parameters to the applet. Contact the author if you have problems.

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