Denial of Service Attacks

Protect yourself against amateur "hackers" who long ago discovered an easy and cheap way to zap you off the Internet and piss you off. It's called "WinNuke," and is done by running a program that exploits a large bug in Win95/NT's networking system, allowing them to bomb your system with extraneous gunk, crashing your computer and forcing you to restart. Two of the WinNuker's favorite hangouts are America Online and the chat program ICQ, but they can target you from any of a zillion Web sites or other ISP's as well. The program is freely available on the Internet, can most likely be turned up by a simple search on any major search engine, and is easy for anyone with a Unix account to run. (Other programs like mIRC scripts allow the zapper to go through an entire IRC channel and nuke everyone at once. Fun, huh?) Well, there's an easy solution. Go through Microsoft's Web sites and download two patch files, VIPUP11.EXE and VCTPUPD.EXE. (The Web site addresses are as follows:

support.microsoft.com/download/support/mslfiles.Vipup.exe and ...vctpupd.exe, where the rest of the URL is the same as the VIPUP address. Download 'em both to a temporary folder. Double-click the VIPUP11.EXE icon, let it install itself, then do the same to the VCTPUPD.EXE icon. Restart your computer. (Make sure you install the two in this order; installing them backwards wipes out VCTPUPD.) Now, update your Winsock connection by installing the two Winsock updates in the "Updates" section below. Delete the four original downloads from your hard disk, and prepare to sneer at the little WinNukers.

Don't get too happy now that you've inoculated yourself against the nukers. Several other "denial-of-service" (DoS) attacks similar to WinNuke are making Net users grind their teeth. One called "The Ping of Death" and a cousin, "Teardrop," exploit known holes in TCP/IP implementation, as does the "SYN" attack and its mutant cousin, "Land." The "Smurf" attack targets your Internet protocols directly and causes major net congestion, while the "UDP Flood" uses the widely accepted User Datagram Protocol to flood LANs and PCs with useless data. The good news: Most problems generated by these beasties are experienced by networked PCs who belong to targeted LANs. The home user isn't seeing these very often. Still, forewarned is forearmed; check out the good people at www.cert.org at Carnegie Mellon University for the latest info about these critters and how to shield yourself from them. Also look into Microsoft's security site at www.microsoft.com/security.

More about security: it's absurdly easy for amateur hackers to invade your PC over the net, root around in your files, even reformat your hard drive. Yeesh. Get a quick security check from ShieldsUP! at grc.com/default.htm. You'll need to download a very small program which, after you connect to the Internet, allows the ShieldsUP site to probe your computer for security breaches. Are they trustworthy? I hope so.... Anyway, this site contains tons of information on how to seal security breaches, firewalls, etc. etc., so it's worth a visit. Forewarned is forearmed. If you want to know just how easy legal hacking is, visit the Happy Hackers at www.happyhacker.org and be prepared to be shocked. These guys seem harmless, but there's plenty of people out there who aren't. Another site worth visiting is HackerWhacker, at www.hackerwhacker.com. HackerWhacker scans over 130,000 possible port addresses on your PC for security flaws and examines your Windows NetBIOS configuration. HackerWhacker's first scan is free, but subsequent uses cost $10 per scan (or you can pay $30/month for unlimited scans). Another place for free PC scanning is

www.pcflank.com/, and DSL Reports offers broadband scanning at www.dslreports.com/ Others that are useful can be found at

www.vulnerabilities.org/ and www.it-sec.de/vulchke.html.

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How to Recover From a Hard Disk Change

I recently had to upgrade the hard drive on one of my PCs. The machine in question runs Windows XP and is attached to a small network. I thought it would be a fairly straightforward task but a few snags reared their head along the way. On with the tale.

Backup
I was lucky inasmuch as the hard drive in question was merely being upgraded. It may be you are upgrading because of a drive starting to cause problems such as an increase in bad sectors or a warning from a S.M.A.R.T. monitoring tool. Worse still, the drive might have just died completely. Whichever the case, the importance of a good backup regime is key to recovering.
How and how often you backup is down to your own situation. What you are trying to achieve is a state such that if you lose everything, you can get back to where you were with minimal fuss. Some people choose to just backup their data and assume they can always reinstall the operating system and applications themselves. This is quite sensible as long as you have the time and can find all the original CDs. A bonus is that you can probably get everything on a single CD-R making backup cheap. On the downside, if you have a heavily customised PC or one that took a lot of configuring then having to do all that again can be a chore.
Another option is to do a full backup once then to do incremental backups that only backup changes. Again, nice and easy but potentially time consuming when it comes to recovery. You are also totally reliant on the full backup and if that turns out to be bad, you are stuffed unless you have done two or more.
I tend to do full backups and regularly as I am positively obsessive when it comes to data loss. Where possible I use a tape streamer and my PCs have a mix of 20Gb Travan, 40Gb DLT and 8Gb Travan. As luck would have it, the PC in question has no tape streamer yet.
As the machines are networked, the obvious thing was to backup across the network to a second PC. One of my PCs is dedicated to video editing and generally has shed loads of free space in-between projects so everything looked ready to go.
Windows XP has a built in program for performing backups which is accessed under Start>All Programs>Accessories>System Tools>Backup. If you don't have this installed, you can install it from your CD like other XP features. The XP backup tool allows you to backup to a file as well as a hardware device so was ideal for the job.

Get it healthy
If your hard drive has started to have read problems, run scan disk or Norton Disk Doctor over it first to try to get it as healthy as possible before continuing. You may not be able to do a full backup so make sure you have the important stuff such as your data before trying to get as much of the operating system as applications as possible.
The PC in question has four partitions set up as C to F. I always tend to build PCs with C: as the boot drive, D: for applications, E: for data and F: for temporary files or games. I decided to backup everything in one hit to a single file. Whenever doing a backup, you should also consider the important system files and particularly the registry which doesn't always get backed up properly unless you specifically set this up.
Another important file with XP is called wpa.dbl. This innocuous file stores the hardware configuration of your machine and is used by the product activation system to prevent piracy. If too much hardware changes, XP thinks it has been copied to a new machine and re-requests product activation. A full backup picks this up but it is worth remembering as it can save you having to reactivate XP if you need to reinstall it.
I kicked off the backup and left it to it for a few hours. When I returned, XP had issued a write error but claimed it had written some 20Gb of data. On the destination PC though it showed a single 4Gb file. Confusion! Then it clicked. Older versions of Windows are limited to a maximum file size of 4Gb and the PC I was writing to was running Windows 98SE. The obvious thing to do was to backup each partition individually. That was set up and again left to it. Back again some hours later and the same problem. Two of the partitions were still bigger than 4Gb. Doh! Why didn't I check? Once again the backup was done but this time the problem partitions were broken up into pieces so the 'Program Files' directory went in to one backup and everything else went in to another. That worked.
Having backed up everything (with verify enabled, naturally) I was ready to swap drives. This stage was thankfully trivial. Simply switch off the PC and disconnect it from the mains before unplugging and sliding out the old drive. The mains bit is important as many PCs still have the motherboard powered up even when switched off at the front. The new drive was set to master via its jumper and then installed.

Whilst it is possible to use backup tools such that you can reinstall from a series of boot floppies which then allow you to reload the main system, I decided to reinstall XP and go from there. To do this, I needed to boot the PC but then enter the BIOS to change the boot device from hard disk to CD before rebooting. The PC then tries to boot from the Windows XP CD instead of the usual hard drive. Don't forget to change it back to hard drive afterwards though.
Installing XP is pretty straightforward apart from it giving you an opportunity to create partitions which you can skip but I took advantage of to set up my C, D, E and F partitions. The XP install is amazingly intelligent and correctly deduced my network and broadband cable connection so once rebooted I could see the rest of the LAN and outside world without any further work.
Next I had to open Backup and use it to restore the different partitions. I worked backwards from F: to C: as the last one would require a reboot. This stage was thankfully trouble free and on completion of restoring C:, the machine rebooted perfectly back to its (almost) original state albeit it with more free disk space free because of the new larger drive.
The 'almost' was the graphics driver. For reasons unknown, the restored machine was working correctly in all respects apart from the monitor and graphics card were still set to default and standard VGA respectively. I reinstalled the monitor's configuration file and downloaded and installed the latest drivers for the Radeon graphics card. On rebooting I was back to a 100% working system.
WPA.DBL

As mentioned before, Windows XP tracks any hardware changes and if enough of a difference is detected, it will reset your machine to a 30 days trial configuration requiring that you reregister it. I was expecting this with a hard drive change but luckily it didn't seem to think this was needed. Be ready for this eventuality though as any other changes you make have a cumulative effect and may force a re-activation of XP.
So there we have it, a successful drive swap. The secret is adequate backups and being able to recover them successfully. There is no point backing up with a program that only exists on the backups as you get a chicken and egg situation that stops you being able restore.

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Looking After Your Printer

Modern colour printers are actually wonders of the age. With inkjets delivering picolitre droplet size, and resolutions undreamed of a few years ago, they can rival photographic prints if you're into digital photography, or take a passable stab at simulating the appearance of laser output if you demand the very best by way of text.
But it's wise to, periodically, run through one or two maintenance routines if the best is to be preserved. You may, for example, notice some colour banding from an inkjet, or some staggering of edges in sharp photographs due to misaligned vertical lines.

The graphic was taken from the Utilities menu of the Epson Stylus Photo C83, which was reviewed in PPC, but it's typical of the sort of facility printer manufacturers provide for maintaining their printer output in top condition.

The status monitor tells you how much ink remains in your colour and black cartridges, and these days that's more accurately judged - if the manufacturers are to be believed - by the incorporation of a chip in each cartridge which gauges the ink levels, even as you print.

The fact that it also means it's more difficult to find much cheaper compatibles is also a factor, though these are now beginning to appear on the market. The manufacturer won't recommend the use of compatibles, of course, and their use will probably invalidate the printer's guarantee, but wisely chosen they can cut costs significantly, and just might be worth the risk. I use them myself.

Ink nozzles
The Nozzle Check (or its equivalent) should be used if you notice that your printer output has gaps of colour, or feint areas. If you get this, use the Head Cleaning facility. What this does is clean out the printer's ink nozzles. But be aware that it does this by squirting ink through them, relying on the solvent effect of the liquid ink to dissolve residues that may have resulted from the drying out of ink after a print job.

The consequence, of course, is that a significant amount of ink is 'wasted', because the ink passes through the nozzles to waste, but it's a necessary evil if output has deteriorated to this noticeable extent. You may, in fact, have to apply the Head Cleaning facility more than once to clear the jets, but don't overdo it. Check the output after each cleaning cycle by printing a test picture, and before you repeat it.

If the above process does not succeed, you might try the special cleaning fluid cartridges that ink specialists supply. They don't always work, however; sometimes the job is just impossible, in which event it's binning time for the printer.

Head Alignment
Check this as necessary, and look carefully for evidence of misalignment of verticals in the output the printer gives you. Adjust as necessary, and then try a printout again. Usually you'll find that, once set, provided the printer doesn't get a deal of mistreatment, the alignment will be preserved, but you should make a check on any new printer.

Media
Having a huge potential influence on output quality is your choice of media. Papers are closely matched to ink composition by manufacturers, so don't expect the very best if you use other types of either ink or paper.
And don't be caught out by throw-away-price market stall paper packs that claim to be compatible with ink jet printers. Some have entirely the wrong absorbency and will produce nothing but smudge.

Mode
Finally, don't forget that printing mode is important. For the very best output, select the printer's highest resolution…. and then wait for the finished product! It can take considerably longer to make a print than faster modes at lower resolution.
If your printer lets you select enhanced modes, by all means try them. It's just that, by implication, you are messing about with colour balance, and that just might spell trouble if you're after a good colour match. However, they can and do work if the subject is right.

In Conclusion
Look after your printer and it will look after you. A cleanup of the outer case, with nothing but a damp cloth, also pays dividends. But do avail yourself of the facilities the manufacture provides. He knows his machine better than you do, so string along with him if you want continued immaculate printer output.

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