Mersenne Digest Friday, June 8 2001 Volume 01 : Number 859 ---------------------------------------------------------------------- Date: Mon, 4 Jun 2001 01:30:37 +0000 (GMT) From: Russel Brooks <[EMAIL PROTECTED]> Subject: Mersenne: DoS attacks GRC.Com After reading about Steve Gibsons recent problems at: > http://grc.com/dos/grcdos.htm I decided to install Zone Alarm on my home pc. Does anyone have comments on any interactions with Prime95 or any other comments? Cheers... Russ _________________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Sun, 03 Jun 2001 20:07:25 -0700 From: Richard Pardoe <[EMAIL PROTECTED]> Subject: Zone Alarm and Prime95 (NEE: Mersenne: DoS attacks GRC.Com) Have had ZA for about 2 years now. No problems w/ Prime95. Initially, I had all programs (including Prime95) ask for permission to send outbound packets. This was done more for curiosity to see what was trying to go out on my machine. After a while, I let Prime95 automatically have permission. Rich - -----Original Message----- From: Russel Brooks Sent: 03 June 2001 18:31 I decided to install Zone Alarm on my home pc. Does anyone have comments on any interactions with Prime95 or any other comments? _________________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Mon, 4 Jun 2001 00:16:00 -0400 (EDT) From: Jason Stratos Papadopoulos <[EMAIL PROTECTED]> Subject: Re: Mersenne: DoS attacks GRC.Com On Mon, 4 Jun 2001, Russel Brooks wrote: > After reading about Steve Gibsons recent problems at: > > > http://grc.com/dos/grcdos.htm > > I decided to install Zone Alarm on my home pc. Does anyone have > comments on any interactions with Prime95 or any other comments? Zone Alarm is quite nice; I run it continuously. It will stop Prime95 the first time Prime95 tries to contact the server, and after that it's a simple matter to configure the firewall to let prime95.exe through (this is for a PPP dialup account; I can't vouch for anyone with high-speed access). Zone Labs made their firewall application-based rather than port-based, so you don't have to know about firewall administration to use it. Even though the U of Maryland is pretty quiet, my copy still stops about one network scan a day on average (ping, ftp, netbios, etc). Hope this helps, jasonp _________________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Tue, 5 Jun 2001 18:40:49 -0000 From: "Brian J. Beesley" <[EMAIL PROTECTED]> Subject: (OT) Re: Mersenne: DoS attacks GRC.Com On 4 Jun 2001, at 1:30, Russel Brooks wrote: > After reading about Steve Gibsons recent problems at: > > > http://grc.com/dos/grcdos.htm > > I decided to install Zone Alarm on my home pc. Does anyone have > comments on any interactions with Prime95 or any other comments? Prime95 is likely to want to communicate with the server occasionally, you will have to configure ZoneAlarm to permit that. And it's bound to steal a few CPU cycles; probably not enough to be significant, provided your system's network traffic volume is reasonably small. I had ZoneAlarm running on a PC running Windows 95 (at work, and permanently connected to the 'net). I removed it having had a couple of incidents where it locked the system up when the network load became heavy. However people with permanent network connections definitely should have some sort of firewall in place; ZoneAlarm looks OK for protecting you provided your link speed is not much greater than 1 Mbit/sec, i.e. it's just about OK for a DSL connection, but not for sites with true broadband attatchment. The system at work is now sheltering behind a firewall running on another PC running linux. This is beautifully stable. I find the linux firewall easier to configure than ZoneAlarm, but then this area of expertise really is my job. BTW ZoneAlarm, or any other firewall installed at your site, _cannot_ protect you from DoS attacks. You can only filter / reject packets which have arrived; if you are under serious attack, then most likely your net access link will be the bottleneck, so rejecting packets which have already made it through is not much good. You need to get your ISP to filter out damaging stuff before it gets sent to you. Even then there is a limit; e.g. if you are running a web server then you simply can't filter out packets from a DoS attack based on valid TCP port 80 packets without effectively disabling your web server. Fortunately the vast majority of the "script kiddies" that launch DoS attacks have no real understanding of the way in which network protocols work; they're the equivalent of mindless morons who wander down the street kicking in automobile doors at random (for the sake of doing damage) rather than the more sophisticated "joyrider" who knows exactly how to break the locks on some particular models (for the sake of enjoying a drive, at someone else's expense). What ZoneAlarm really _is_ good at is diagnosing software which (unbeknownst to you, the user) is sending messages from your system to the outside world; i.e. spyware. This is a privacy issue, not a network security issue, though I agree it's no less important for that. Regards Brian Beesley _________________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Fri, 8 Jun 2001 19:50:41 +0200 From: "Guido Lorenzini" <[EMAIL PROTECTED]> Subject: Mersenne: Strange behaviour Messaggio in formato MIME composto da pi� parti. - ------=_NextPart_000_0000_01C0F054.4C7307A0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Hi all! Don't like to take up your time, but the behaviour of Prime95 on a = 750@795 Duron, P-1 factoring on 33.3mio exponent (B1=3D350000 and = B2=3D4025000), is quite strange. The Duron completed the stage 1 without = any problem, but during the stage 2 the time per iteration has slow down = a lot, from 0.650 sec/it to many minutes for just one iteration. Above all the pc is unusable, so I've decided to edit manually = worktodo.ini: from Test=3D33306743,68,0 to Test=3D33306743,68,1 to force prime95 to skip the factoring stage when the process was done = for about 30% (The intermediate file mX306743 sizes 8,132 KB). I've tried to put everything on another machine but with no results: the = behaviour was the same. Skipping the P-1 factoring stage shouldn't invalidate the LL test, as = George says in undoc.txt: You can force prime95 to skip the trial factoring step prior to running a Lucas-Lehmer test. In prime.ini add this line: SkipTrialFactoring=3D1 By the way: I've done it but apparently nothing has changed. If I've = understood properly, adding this line is like to manually edit = worktodo.ini. Isn't it? Is it better if I force prime95 to start p-1 factoring from zero once = again, hoping any problem occurs this time? What may be the problem? Has = anybody ever observed something like this? Last question: is it normal that prime95 runs a self test each time it = is going to test with different FFT sizes? =20 Thank you in advance for answering and best regards from Italy. Guido72 - ------=_NextPart_000_0000_01C0F054.4C7307A0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable <html xmlns:o=3D"urn:schemas-microsoft-com:office:office" = xmlns:w=3D"urn:schemas-microsoft-com:office:word" = xmlns=3D"http://www.w3.org/TR/REC-html40";> <head> <meta http-equiv=3DContent-Type content=3D"text/html; = charset=3Diso-8859-1"> <meta name=3DProgId content=3DWord.Document> <meta name=3DGenerator content=3D"Microsoft Word 9"> <meta name=3DOriginator content=3D"Microsoft Word 9"> <link rel=3DFile-List href=3D"cid:[EMAIL PROTECTED]";> <!--[if gte mso 9]><xml> <o:OfficeDocumentSettings> <o:DoNotRelyOnCSS/> </o:OfficeDocumentSettings> </xml><![endif]--><!--[if gte mso 9]><xml> <w:WordDocument> <w:View>Normal</w:View> <w:Zoom>0</w:Zoom> <w:HyphenationZone>14</w:HyphenationZone> <w:EnvelopeVis/> <w:DoNotOptimizeForBrowser/> </w:WordDocument> </xml><![endif]--> <style> <!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman";} @page Section1 {size:595.3pt 841.9pt; margin:70.85pt 2.0cm 2.0cm 2.0cm; mso-header-margin:35.4pt; mso-footer-margin:35.4pt; mso-paper-source:0;} div.Section1 {page:Section1;} - --> </style> </head> <body lang=3DIT style=3D'tab-interval:35.4pt'> <div class=3DSection1> <p class=3DMsoNormal><font size=3D3 face=3D"Times New Roman"><span = lang=3DEN-GB style=3D'font-size:12.0pt;mso-ansi-language:EN-GB'>Hi all!<br> Don't like to take up your time, but the behaviour of Prime95 on a = 750@795 Duron, P-1 factoring on 33.3mio exponent (B1=3D350000 and B2=3D4025000), = is quite strange. The Duron completed the stage 1 without any problem, but during = the stage 2 the time per iteration has slow down a lot, from 0.650 sec/it to = many minutes for just one iteration.<br> Above all the pc is unusable, so I've decided to edit manually = worktodo.ini:<br> from Test=3D33306743,68,0<br> to Test=3D33306743,68,1<br> to force prime95 to skip the factoring stage when the process was done = for about 30%<o:p></o:p></span></font></p> <p class=3DMsoNormal><font size=3D3 face=3D"Times New Roman"><span = lang=3DEN-GB style=3D'font-size:12.0pt;mso-ansi-language:EN-GB'>(The intermediate = file mX306743 sizes 8,132 KB).<br> I've tried to put everything on another machine but with no results: the behaviour was the same.<br> Skipping the P-1 factoring stage shouldn't invalidate the LL test, as = George says in undoc.txt:<br> <br> You can force prime95 to skip the trial factoring step prior to<br> running a Lucas-Lehmer test. In prime.ini add this line:<br> SkipTrialFactoring=3D1<br> <br> By the way: I've done it but apparently nothing has changed. If I've = understood properly, adding this line is like to manually edit worktodo.ini. Isn't = it?<br> <br> Is it better if I force prime95 to start p-1 factoring from zero once = again, hoping any problem occurs this time? What may be the problem? Has = anybody ever observed something like this?<br> <br> Last question: is it normal that prime95 runs a self test each time it = is going to test with different FFT sizes?<o:p></o:p></span></font></p> <p class=3DMsoNormal><font size=3D3 face=3D"Times New Roman"><span = lang=3DEN-GB style=3D'font-size:12.0pt;mso-ansi-language:EN-GB'> <o:p></o:p></spa= n></font></p> <p class=3DMsoNormal><font size=3D3 face=3D"Times New Roman"><span = lang=3DEN-GB style=3D'font-size:12.0pt;mso-ansi-language:EN-GB'>Thank you in advance = for answering and best regards from Italy.<o:p></o:p></span></font></p> <p class=3DMsoNormal><font size=3D3 face=3D"Times New Roman"><span = lang=3DEN-GB style=3D'font-size:12.0pt;mso-ansi-language:EN-GB'><![if = !supportEmptyParas]> <![endif]><o:p></o:p></span></font></p> <p class=3DMsoNormal><font size=3D3 face=3D"Times New Roman"><span = lang=3DEN-GB style=3D'font-size:12.0pt;mso-ansi-language:EN-GB'>Guido72<o:p></o:p></sp= an></font></p> <p class=3DMsoNormal><font size=3D3 face=3D"Times New Roman"><span = lang=3DEN-GB style=3D'font-size:12.0pt;mso-ansi-language:EN-GB'><![if = !supportEmptyParas]> <![endif]><o:p></o:p></span></font></p> </div> </body> </html> - ------=_NextPart_000_0000_01C0F054.4C7307A0-- _________________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ End of Mersenne Digest V1 #859 ******************************
