Computer Tips -Tech Info

Category: Computers

  • Approaches to beating form spam submission

    I’ve replaced bare email addresses on web page with either an encoded variation of the email or with a contact form to discourage spam scrapers and other automated tools from using it for a spam magnet. Well, it seems there are some tools that automatically submit forms – after all that’s what’s brought us the annoying captcha’s we see everywhere now. (You now those pictures with squiggly letters and numbers that you sometimes have to redo two or three times if you can’t read it correctly.) Well, Sans is talking about some interesting alternatives to the traditional captcha for protecting a form from automated spam bots.

  • Good idea to help limit phishing attacks

    I saw this a few weeks back and think it’s a good idea. Essentially why don’t we have a .bank domain registration and limit it to just financial institutions the way .gov is limited to government registrations. (and .mil for military, .edu for educational institutions…..) Let’s face it, anyone can register a .com .net or .org – maybe instead of increasing the number of Top level domains that ANYONE can register in, maybe we need to tighten the restrictions and add a few new TLD’s that would be more closely restricted. There’s already a .museum, .bank would be a good one next.

  • Network swiss army knife

    There’s no better way to say it, netcat is SOO useful, and there is an encrypted variation… cryptcat, you can do quite a few interesting and useful things VERY easily with these two utilities. (*It’s one of the utilities I used to image a live running system to a file on a network server.) The source is available from the previous two links. There are binaries for windows for both netcat and cryptcat available here, but with all such tools you should be wary of where a precompiled binary comes from.

  • Major botnet building and the massive jump in spam

    For a few months now (since the demise of bluefrog actually) I’ve noticed that the level of junk mail has gone up on my own mail server. Yes, I use spamassassin to filter and tag, but the volume of stuff that’s tagged has gone up (as well as the volume that slips through.) I’ve had to flush out the bayes filter more than I would like after some massive bayes poisoning attempts (those messages with lots of random words or text.) I’ve also been following news on the topic and thought I’d detail some of it here for those that haven’t been paying attention.

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  • Create a sitemap for Google

    WordPress has a great plugin available to automatically keep your google sitemap updated, but I’ve done a few static websites in the last few days and just wanted a good, quick, web generated sitemap. http://www.xml-sitemaps.com/ seems to do the job quite well, it generates a Google sitemap xml, compressed xml, and a ror sitemap (I hadn’t heard of that yet..) It also generates a text file url-list and a html sitemap.

  • VMware guest unable to access USB devices

    I ran into this some time back and found the solution a few months later and was reminded today to document it here…. The situation is this… Linux host for VMWare server, the guest machine has usb support and in vmware, you can go to VM, Removable devices and in spite of the fact you have usb devices on the system, nothing is listed as available to use in the VM. Well, it seems this is not an isolated problem. First you need to be sure the usb device is not in use by the host system. But, there’s something else that you need. VMWare uses usbfs to keep track of usb devices and a few distributions ( Ubuntu Linux 6.06 SUSE Linux 10.1, SUSE Enterprise Linux Server 10, Mandriva Linux 2006, SLES9 SP3 64 bit) don’t enable it by default. ( mount -t usbfs none /proc/bus/usb ) should do the trick (as root) or you could set it in fstab usbfs /proc/bus/usb usbfs auto 0 0 (and now I’m thinking I may have already posted this once…. )

  • Vmware Server web interface tricks…

    I haven’t been overwhelmed with VMware server’s web interface. You can start a virtual machine, or see statistics, but you can’t create virtual machines. Well, from the VMWare forums I did find a couple interesting “hidden” features. First, is a file manager at https://youriphere:8333/fm-properties and second is a GSX interface (which gives the ability to create a NEW virtual machine) at https://youriphere:8333/overview (the direct link to creating a new vm is https://yourip:8333/vmcfg-gsx )….

  • PDF printing in Ubuntu

    One of the things I have a tendency to do is save licence key – web confirmation pages to a pdf by printing. It gives a good capture of the document and saves me from actually having another paper to find a place to file. But, ubuntu (dapper) doesn’t seem to be setup for pdf printing by default. Fortunately, it’s not too hard to set up…. install cups-pdf (apt-get install cups-pdf), navigate to System -> Administration -> Printing and doubleclick to add a new printer… no pdf printer is detected… there must be work to do (click cancel). As root (“sudo nautilus”) navigate to Filesystem, then /usr/lib/cups/backend – right click cups-pdf and select properties and check “set user id”. Now, try to add a printer again and you should see PDF Printer, add it with the Generic, Postscript Color Printer (Rev 3b) driver, name it PDF-printer or something like that and now you should have PDF’s dropped into a folder in your home directory named PDF.

  • Linux software raid notes

    Here are a few other notes on linux software raid. I created a directory called raidinfo to keep information in to make it easy to maintain the raid array. First… from the software raid howto, I’ve done the following….

    sfdisk -d /dev/hda > /raidinfo/partitions.hda
    sfdisk -d /dev/hde > /raidinfo/partitions.hde

    So…. I’ve now got a good snapshot of the partitioning data. When I hooked up an external usb drive to add to the array, all I needed to do is this…

    sfdisk /dev/sda < /raidinfo/partitions.hda (more…)