Tag: TFTP

[Solved]TFTP: Error code 2: Access violation

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This post is an extension of my original post on TFTP: How to Setup TFTP. Although the post was written for Ubuntu, the same idea can be applied to all systems.

So, here is our problem. You set up a TFTP server. It starts fine. You upload a file, it gives no error. Now, you try to download a file, it throws you an error:

tftp> get myfile.jpg
Error code 2: Access violation

If you google the error message, Error code 2: Access violation on the web, you’ve probably noticed many solutions, some of them are very creative, such as running a touch command to create the file before downloading it etc. Before you try those solutions, ask yourself this question first: Do you want to touch 100 files before you download 100 files?

Anyway. I am not sure what cause the TFTP gives the error message: Error code 2: Access violation. However I never experienced this error in my system before with my configurations and settings. Therefore, I am going to share you my configurations for your reference.

My TFTP Configuration:

service tftp
{
   protocol = udp
   port = 69
   socket_type = dgram
   wait = yes
   user = nobody
   server = /usr/sbin/in.tftpd
   server_args = var/lib/tftpboot -s
   disable = no
}

There are couple things you need to pay attention. First, my TFTP root directory is /var/lib/tftpboot, and in my configuration file, I skip the first /. Second, I put a flag, -s in the server_args. That helps to keep TFTP from complain.


Next, the permission of the TFTP root directory plays an important role. Make sure that the permission and ownership are set correctly.

sudo chown -R nobody:nobody /var/lib/tftpboot
sudo chmo7 -R 777 /var/lib/tftpboot

Now, you can simply restart the system:

sudo service xinetd stop
sudo service xinetd start

and try to put a file and download it back:

tftp localhost
tftp> put myfile.jpg
Sent 56733279 bytes in 5.7 seconds

tftp> get myfile.jpg
Received 56733279 bytes in 5.7 seconds

That’s it.

Happy TFTP.

–Derrick

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How to Setup TFTP on Ubuntu 11.10

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Recently I decide to jump into the pool of using diskless Ubuntu. Basically the client computer downloads the necessary files from the Ubuntu server every time during the boot. To keep things simple and easy, Ubuntu does that by using TFTP. So the first step is to set up a TFTP server on the server. For those who haven’t heard of TFTP, it is similar to FTP, except that it has no security feature, and the function is extremely limited. Anyway, here is how to set up a TFTP server on Ubuntu 11.10:

Installing TFTP sounds easy. However, I’ve heard that many people experienced many issues during the installation, such as Error code 2: Access violation issue. That’s why I create this tutorial. If you follow exact the same steps, you will not experience any problem.

First, let’s install all the necessary packages:

sudo apt-get install xinetd tftpd tftp -y

Next, we need to create a configuration file:

sudo nano /etc/xinetd.d/tftp

Put the following content into the file.



service tftp
{
   protocol = udp
   port = 69
   socket_type = dgram
   wait = yes
   user = nobody
   server = /usr/sbin/in.tftpd
   server_args = var/lib/tftpboot -s
   disable = no
}

In the server_args, I have var/lib/tftpboot, which represents the location of the tftp root, i.e., /var/lib/tftpboot. Notice that I skip the root /.

Now let’s change the ownership of the directory:



sudo mkdir /var/lib/tftpboot
sudo chown -R nobody:nobody /var/lib/tftpboot
sudo chmod -R 777 /var/lib/tftpboot

and start the TFTP service:

sudo service xinetd stop
sudo service xinetd start

Verify the TFTP is running correctly or not:

netstat -na | grep LIST | grep 69

You should see something like this:

tcp        0      0 0.0.0.0:69              0.0.0.0:*     LISTEN

Test: Upload a file to TFTP Server

Now let’s test the TFTP server by logging into the server first:

tftp localhost

and upload a file:

tftp> put myfile.jpg
Sent 56733279 bytes in 5.7 seconds

Quit:

q

Make sure that file has been uploaded:

ls -l /var/lib/tftpboot

Test: Download a file from TFTP Server

Now, let’s go to a different directory and download the file we just upload.

cd some_other_directory

and log in to the tftp server again:

tftp localhost

and get the file:

tftp> get myfile.jpg
Received 56733279 bytes in 5.7 seconds

You are done.

Troubleshooting (e.g., Error code 2: Access violation)

If you see a message like: Error code 2: Access violation

Make sure that you:
– Follow the exact procedure in this tutorial
– Make sure that the tftp is started with -s flag.
– Check the permission of the directory, i.e., 777
– After you’ve made any changes to the TFTP configuration, make sure that you stop and start the inet service again.
– Don’t forget to quit tftp before retrying the command.

That’s it!

Enjoy TFTP.

–Derrick

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