My company uses Windows Terminal server extensively so most of our users connect via thin clients running Windows CE.  I am currently in the process of pointing all of our thin clients to point to a DNS name rather than an IP.  But there are still several thin clients which are still point directly to an IP address.
For a couple of reasons, I decided it would be a great idea to switch our DNS servers to forward to OpenDNS.  I make the switch late in the evening, check that I can browse the internet, and figure all is good.  Wrong.  My slumber is quickly broken by a 6 AM wakeup call that certain thin clients are unable to connect to our terminal servers.  I determined that it was only the thin clients which were connecting directly to an IP address that were affected.  I test the usual suspects.  I can ping the thin clients, IP settings look correct, everything looks in order and I am stumped.  Since these are pointed directly to an IP address DNS should not be a factor.  Or so I thought.
Finally, I find a thin client which is affected and I bust out Wireshark.  To my amazement, Windows CE was doing an A record lookup for the IP address.  By its design OpenDNS returns 208.69.32.132 for any A record lookup that doesn’t have a valid record.  So the thin clients were then trying to connect to the OpenDNS IP instead of the IP address which was programmed.

Thank you Microsoft for leaving out the “IF <> IP THEN Do a DNS Lookup” logic.

To be fair, most, if not all, of these thin clients are pretty old so this may have been fixed.  Nonetheless I found it pretty backwards.

After years of using Windows mobile phones I switched to an iPhone.  I got pretty to getting the iPhone’s VPN to work with our Sonicwall 3500, but I ran out of patience.  According to the Sonicwall a connection was established, but the iPhone would immediately disconnect.  My patience ran out so I decided to take a swing at setting up a PPTP server.

Quick note  - anything that is in bold you should be able to use exactly.  Anything that is in bold and in italics will need to be updated according to your environment.

Of course I am building this as a virtual machine, so I started with a fresh image of Ubuntu 8.04 JeOS.  After you have your server running and up to date, you just need to install pptpd.  Just run sudo apt-get install pptpd.

Now we need to configure PPTP. At minimum you will need two additonal IP addresses on your LAN. First, using your favorite text editor open /etc/pptpd.conf for writing.  We need to modify or add the following lines:
localip 172.16.0.2

remoteip 172.16.0.3-4

The localip IP is the virtual / secondary IP of your VPN server.  The remoteip IP(s) is the IP(s) that VPN clients will be given.

You will also probably want to specify DNS servers for your VPN clients to you use. If so, open /etc/ppp/pptpd-options for editing.  You can specify up to two DNS servers by adding or modifying the line ms-dns 172.16.0.5.

Next we need to setup an account for each VPN user.  Open /etc/ppp/chap-secrets for editing.  Add the following for each VPN user.

username pptpd password “*”

Finally, we need to tell Ubuntu to forward the VPN client traffic.  Add, edit or uncomment the following line in /etc/sysctl.conf.

net.ipv4.ip_forward=1

At this point I rebooted - I wasn’t sure if it is required for sysctl.conf change to take place.  Modify your internet firewall to allow PPTP connections (TCP port 1723 and protocol ID 47) to your server and you should be all set.  If you just need to restart the pptpd daemon run sudo /etc/init.d/pptpd restart.

This combined with an SSH client is going to come in very handy for those occasions when a server needs to be rebooted and I am busy enjoying a pint or two.

Wow two posts in one day

I just came across WINEXE and I am so excited I had to share.  It is basically PSEXEC for Linux.  Anyway you can get it here http://eol.ovh.org/winexe/

It gets really cool when you execute cmd on the remote machine…

I recently updated the firmware on my 8525 and as a result I could no longer tether my phone and laptop. As it turns out Microsoft has switched from using DUN (dial up networking) to PAN (personal area network). There were numerous guides available but I couldn’t quite get any of them to work. Below is what ended up working for me.  It is a piecing together of a few guides.

First I had to setup a connection between my phone and the laptop. While I tried several approaches, what I believe finally worked was making the connection from my phone to my computer. Next, I figured out my phone’s bluetooth MAC address. To do this run ‘hcitool scan’. This should return something along the lines of 00:12:D2:02:69:0F. I then ran the following commands:

’sudo modprobe bnep’
’sudo pand –role PANU –connect 00:12:D2:02:69:0F’ <- replace with the MAC you get from above
’sudo dhclient bnep0′

That was it for me. You may have to down some interfaces. For example, ’sudo ifconfig eth0 down’.

To make it more convenient  I saved the above commands in a shell script.

I threw together a script Set_NTP.zip this afternoon to automatically setup NTP on an ESX 3.x server. There are basically 3 ways to run it:

Interactively - enter every NTP server name / IP.

Semi-automatic - specify a file that has a list of NTP servers, you are shown the servers and then you must confirm that they are correct.

Fully automatic - specify a file with a list of NTP servers and they are added with out prompting.

If you look at the very top of the file there are some examples on how to use the file. Any comments or feedback are appreciated.

Since my Comcrapstic Internet connection is unreliable at best, I often have to connect to the Internet by other means.  My neighbors actually lock down their access points so that usually leaves me with just my cell phone.  After many hours researching and failing, I came across this article.  Low and behlod it did the trick - with one bar of signal on Cingular’s UMTS network I was able to get 389 Kbps down and 274 Kbps up.  The only difference I had to make was I used “sudo /etc/init.d/bluez-utils” in place of “service bluetooth”.

Recently I designed and installed the computer system in my brother’s new dental office. Luckily, we came across Open Dental and decided it would be a good fit. Since the office is as paperless as possible it is important that the computer system be as reliable as possible. The Open Dental server is pretty basic needing just SAMBA and MySQL. Enter Linux. I researched and played around a bit and decided to jump on the Ubuntu bandwagon for this.

For various reasons, I decided that we should run this as a Virtual Machine using VMWare’s Virtual Server on top of some type of Windows Server platform. One major reason is my brother is already familar with Windows so I can easily walk him through basic troubleshooting steps.

So I decided that to keep with the theme of sharing I would offer up the Open Dental Virtual Appliance for anyone who may be intersted in trying it out.

To try this out you need to either download VMWare Player or VMWare Server and this ZIP file.

To login to the server use “opendental” for the username and password.

Please note that this is a very early release - I make no promises that it will not mess anything / everything up. I plan to test it much more (this image has hardly been tested); also I plan to throw some documentation together. Additionally, I will explain my backup strategy which will include a release of an Rsync virtual machine.

I have a few days under my belt running Ubuntu and overall everything seems to be working great. I was able to get my wireless working - my router just needed to be restarted. I opted to install Thunderbird for my e-mail. At first, I was worried about keeping e-mail on my phone in sync with Thunderbird. However, once I quit trying to use POP and switched to IMAP things were much better. I was also very pleased to see that I can still sync my phone with my XP virtual machine via USB.

I think there are only a few things I still have to work out. Although, I think / hope I am making some progress, I still have not had any success connecting to the internet through my aircard or cell phone. Also, I have not found an open source alternative to MS Access. So I still have to occasionally boot up the virtual machine. Luckily, that is not very frequent and I can easily live with it.

There are many things I like thus far. I am really growing to like the multiple virtual desktops. I am also pleased that so far the transition has been fairly painless. I have found the ubuntu forums to be a great reource. The wi-fi light does not work the same as in Windows. Luckily, ‘iwconfig’ tells me if the radio is on or off. While less convenient, it still does what I need. In general I would setting up wi-fi is not yet up to par with Windows. There are still some quirks to work out (sometimes the machine will not properly reboot or shutoff), but overall I am very pleased with my progress.

Yesterday, I cleaned up my XP installation and ghosted my laptop. I will eventually create this as a virtual machine following the steps here. Anyway, I went for broke and installed Ubuntu, which is almost painfully easy to install. I have used Ubuntu as a virtual machine before so it is not entirely foreign to me. It is impressive how usable it is out of the box.

The first step getting the system up to date. This can be accomplished through the gui, although I usually opt for the command line. If you enjoy doing things the difficult way go to a terminal window and run ’sudo apt-get update’ and then ’sudo apt-get upgrade’. Unfortunately, I have found that my speeds and connections to the update mirrors has not been all that reliable. I am not sure if that is something specific to me or not. I just run the above commands multiple times until they successfully complete. Luckily, it appears that the upgrades and updates continue where they left off.

With the exception of my cellular air card, most everything appears to be working. There are some issues with my wireless card, but I am hoping they are minor. The little green light that shows that the card is enabled does not light up. As it turns out the hot keys do work (Fn+F2) the light it just not active. I did find an article last night which mentioned how to enable the light so I will have to try it out - and find the article again… During my very brief test last night I couldn’t connect to my access point, but I could see it. I was able to see my router, just not get a dhcp address from it.

So anyway, I am in the process of getting ready to install VMWare Server as outlined in the steps here. After that it’ll be time to convert the ghost image to a virtual machine. Then I will dig into it and get it setup for day to day use.

Well I have decided it is time for me to make the switch to Linux - specifically Ubuntu. I am going to try and document the move in hopes that it may help some others out. Here’s the rough plan…

1. Clean up the existing Windows XP installation
2. Convert current XP installation to a virtual machine on my desktop
3. Install Ubuntu on my laptop
4. Install VMWare server and then move my old XP install back as a virtual machine

In the end I hope to convert my Dell D610 laptop to Ubuntu and without loosing any functionality. My main concern is hardware comptability. I have a feeling my biggest challenges will be getting my Cingular Sierra Wireless 860 to work and also tethering my Cingular 8525 phone.