Technology How To’s

Poking a hole in that pesky firewall.

Posted by Rick on in Hacking, Linux, Technology How To's, Unix 0 Comment

Poking a hole in that pesky firewall.

There are more than a few ways to access a firewall.  I will be giving a brief tutorial for one of the more common methods. Called “poking a hole”, or professionally called an SSH back door.  Please, please be careful with this, any script kiddy with 30 lines of code can exploit an SSH server.

This is a great post by IBM detailing it pretty well. If you have any question feel free to leave a comment and I will assist you.

  1. SSH from ginger to blackbox.example.com with the -R flag. I’ll assume that you’re the root user on ginger and that tech will need the root user ID to help you with the system. With the -R flag, you’ll forward instructions of port 2222 on blackbox to port 22 on ginger. This is how you set up an SSH tunnel. Note that only SSH traffic can come into ginger: You’re not putting ginger out on the Internet naked.You can do this with the following syntax: ~# ssh -R 2222:localhost:22 thedude@blackbox.example.com

    Once you are into blackbox, you just need to stay logged in. I usually enter a command like:

    thedude@blackbox:~$ while [ 1 ]; do date; sleep 300; done

    to keep the machine busy. And minimize the window.

  2. Now instruct your friends at tech to SSH as thedude into blackbox without using any special SSH flags. You’ll have to give them your password: root@tech:~# ssh thedude@blackbox.example.com .
  3. Once tech is on the blackbox, they can SSH to ginger using the following command: thedude@blackbox:~$: ssh -p 2222 root@localhost
  4. Tech will then be prompted for a password. They should enter the root password of ginger.

Thanks IBM.

OSX 10.5.7 Update Issues

Posted by Rick on in Apple, Technology How To's, troubleshooting 0 Comment

OSX 10.5.7 Update Issues

It’s comforting to know that when Apple screws up, they do it but good.

Not since the days of Tiger has a dot release from Apple done so much damage. On the surface, 10.5.7 is a very important update. A lists of fixes includes the usual round of security fixes, fixes for network performance, updates for Camera RAW support, among several other fixes. But, initially the Software Update version was throwing up errors “digital signature for the package is incorrect.” Apple rapidly fixed this but it underscores the importance of having good backups and a clean file system.

Afterwards, others started reporting BSOD or Blue Screens of Death after the update was done. Having originated on Windows, the BSOD is now available in Leopard, a nice, if unintended bonus from Apple.

Luckily this problem seems to be fairly easy to fix:

  • Wait for Hard drive access to stop
  • Hold Power button down until computer shuts off
  • Hold shift button down and power computer on to boot into safe mode
  • Use regular user name and password to login if asked
  • type reboot to reboot the computer

    • The next issue to commonly pop up is messed up display resolutions for non-Apple monitors. People are finding themselves stuck in 1920×1080! Resetting the PRAM (Hold down the Command, Option P and K keys while booting until it chimes three or four times) seems to fix for some.

    For some of us REALLY unluckily people, the update gets stuck part way. After letting it sit for an hour at 33% there was no choice but to reboot the computer. Upon booting back up, OS X is not able to fully boot up. In one machine I was able to fix by going into safe mode, then issuing the softwareupdate -l -a command to finish the download and install.

    On my Macbook, it was a full reinstall.

    How To: Use Google to search Usenet Archives

    Posted by Rick on in google, Technology How To's 2 Comments

    How To: Use Google to search Usenet Archives

    Usenet’s usability has degraded a lot in recent years. But back in it’s day it was probably the most useful tool to share knowledge around. The grains of knowledge contained in Usenet even now are immeasurable.

    So go to: http://groups.google.com/advanced_search?q=&

    And you’ll be presented with Google’s Advanced Search. This one has several additional options to help find information. Subject, Author, and even dates are possible. But the hidden feature is the groups section. Instead of just Google Groups, any newsgroup name can be used such as alt.religion.

    Enter in your requested search terms, modify the advanced search options, hit OK and be amazed at the power that is Google Search.

    How To: Use Dump to back up a full filesystem

    Posted by Rick on in FreeBSD, GPL, Linux, Technology How To's, Unix 0 Comment

    How To: Use Dump to back up a full filesystem

    Way back in the day when tape drives first started being heavily used to do backups of Unix machines, the dump command was created. In typical Unix simplicity the dump command “dumps” files from one device to another device. This can be a tape drive, a hard drive, even a network share. rsync does a similar process but is meant for immediate use of those files.

    First step is to be sure dump is installed. If not use, rpm, yum, port, apt-get, or your local repository method to install dump on your system.

    The quickest command to get started is: dump -0 -j9 -f /pathtosavebackup /pathtobackup

    This would give us a down and dirty dump of the requested path, or if / is used in the second part of the command, the full file system starting at the root.

    -j9 tells the command to compress (using tar) the file as much as possible.

    -f defines the device (or filesystem path) to dump too. Keep in mind that this command could not be used to dump files from the local filesystem back to the local filesystem.

    The bad news is that this will take quite a while depending on how much data needs to be dumped, how fast the hard drives (or tape drive) is, and if backing up to a network share, how fast the ethernet connection is. In my tests 100gb filesystem got compressed down to 23gb, and took about fives hours across a 10/100 connection.

    After the dump is done, tar can be used to unarchive the file to a new file system.

    How To: Create and Import vcf VCards

    Posted by Rick on in Apple, Microsoft, Technology How To's 1 Comment

    How To: Create and Import vcf VCards

    VCards are simply virtual business cards used to exchange contact information. They are easily recognizable with the .vcf file extension. Vcards have rapidly become a universally excepted way of transferring contact information between devices. They can be sent to most phones such as Blackberries and iPhones, or to all the popular Email programs and multiple contact collection programs.

    The first step in creating a VCard is actually the hardest. Below is an example of my own VCard:

    BEGIN:VCARD
    VERSION:2.1
    FN:Rick Hamell
    N:Hamell;Rick;;;
    TEL;PREF;CELL:971.555.5555
    EMAIL;INTERNET:rick@hamell.net
    URL:http://RickHamell.com
    URL:http://www.1nova.com/blog
    URL:http://www.1nova.com/photoblog
    UID:efc38667f3b9ab04495f9c54d2587950
    REV:2008-10-27T20:47:59Z
    END:VCARD

    As can be seen it shows all the important contact info that would be found in any contact program. In addition to Email addresses it includes my phone number and URL to my website.

    Many programs such as Apple’s Address Book, or Microsoft Outlook will allow exporting a contact to a VCard file. They can also be edited with a text file as long as the conventions in structure are observed. The easiest method is to use an online generator. I prefer Wacomenance.co.uk but the one at Vicintl.com is more streamlined and compatible. Keep in mind that while MOST programs should read all the fields in a VCARD, some will drop fields such as second and third email addresses.

    After creating a card the next step is to import it in to the preferred Contact Program.

    Microsoft Outlook:

    • Click on File menu, then choose Import And Export.
    • Click to select the Import a vCard file (*.vcf) check box, and then click Next.
    • Select the vCard file, and then click Open.

    Microsoft Entourage:

    • Open Entourage
    • Click on Address Button
    • Drag .VCF file to upper right hand window of Entourage

    Apple Address Book:

    • Simply Double Click on the .VCF Card

    Mozilla Thunderbird:

    • Attach VCard in Email to self
    • Click on VCard
    • Click OK in “New Card for” Dialog Box

    Keep in mind that VCards only really work well with one contact at a time. This is not the way to export or import a fully populated address book. Also, it’s best to be careful where the file goes as it could be used for malicious purposes. Only send the file out to people known to you.