Blank Window When SSH Forwarding X11 Sessions

There are a number of applications running on our servers that have GUI’s that I need to display on the Mac in my office. While the traditional method of exporting the server-side display to my desktop works, it is inherently insecure because the entire session, including any passwords that may be sent are all transmitted in clear-text.

Better to use SSH X11 forwarding. This way the entire session is encrypted and nobody can snoop your passwords. The process of using SSH X11 Forwarding goes something like this:

On the server-side (the machine from which you want to forward the display, make sure this line is in your /etc/ssh/sshd_config file:

X11Forwarding yes

If you had to add it, restart the sshd service.

/sbin/service sshd restart

Now, from the client-side (the machine on which you want to display the forwarded X11 application) connect to the server-side machine with the -X flag. Like so:

ssh -X username@remoteserver

Now you should be able to start X applications and have them display on your client machine through an ssh tunnel. If you are like me, however, some Java applications will not display correctly. Instead of popping up a window with the full application in it, I would only see a totally useless blank window. This frustrated me for months until I found this article at kraftek.com that details how to resolve the problem.

It turns out that all you have to do is put this line in the ssh_config file on your client-side:

ForwardX11Trusted yes

After logging out and back into the server-side machine, everything worked perfectly.

MySQL Connection Over an ssl Tunnel

Rather than leave MySQL open to the world, consider firewalling it off and tunneling a connection over ssh.

This command will allow you to connect to your MySQL server on hostname.domain.com on localhost:7777.

ssh -L7777:127.0.0.1:3306 user@hostname.domain.com

Mishap with a Truck Full of Missiles

A truck full of missiles exploded in a South Korean tunnel Wednesday, but luckily nobody was harmed. Officials have been trying to downplay the explosion, but despite their efforts, it has become international news, resulting in widespread criticism of the South Korean government.

Apparently, the truck was one of the four cargo vehicles carrying warheads and boosters for Nike-Hercules missiles from an air base in Sunchon, South Cholla Province, to another base in Taegu.

The incident seems to be worrying citizens about the lack of security and safety measures in South Korean society. They point to a series of disasters such as the subway fires in Taegu which killed hundreds of people.

From The Korea Times:

The incident also enhances public concerns about the status of military discipline and order, which has been seriously eroded because of the outbreak of serious accidents. In addition, it is expected to prompt the government to replace the obsolete Nike-Hercules missiles with second-hand Patriot missiles as quickly as possible, because they are prone to accidents. Korea is the only country that still operates the Nike-Hercules missiles, which were developed in the 1950s. At present, some 200 are deployed in the country.