Posts Tagged ‘ssh’

More Tab Complete Awesomeness on Ubuntu 9.04

It’s a slightly older post, but after I read Workswithu’s report on the four features that they believed set Ubuntu apart, I had to agree whole-heartedly with the fourth one regarding implementation of auto-complete on the shell. As I was reading, I constantly dropped to the shell to discover new tab-complete features that I didn’t know about, including apt-get that I really didn’t notice but used every day. Anyway, today I discovered yet another.

This kind of defeats the purpose of DNS, but I discovered that if you put a host into the /etc/hosts file on a Ubuntu 9.04, then both SSH and rsync tab-complete for you when you start typing the hostname. I’m not sure about scp, but I’m sure it works the same way.

Extending this functionality further, it would be awesome if I could tab-complete from my known_hosts file, but that doesn’t seem to work.

Anyway, if you find yourself SSHing or rsyncing files to a host or set of hosts all the time, this trick can be very time-saving. Perhaps not quite as time-saving as being able to SSH with the click of a mouse, but often its not very convenient to leave the keyboard just to save a few keystrokes at the shell.

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Filed under How-Tos / Tips : Comments (0) : Aug 5th, 2009

Zenoss SSH Troubles on Ubuntu 8.04

Fresh off a stack installer of Zenoss Core on Ubuntu 8.04, I had a little trouble with SSHing to other hosts using the Zenoss user. When I tried to SSH, I got a this error:
ssh: /usr/local/zenoss/common/lib/libcrypto.so.0.9.8: no version information available (required by ssh)
Segmentation fault

Segfault. That’s not cool..

After doing a quick search on Google, I found this suggestion in a mailing list:
unset LD_LIBRARY_PATH

After ‘unsetting’ the LD_LIBRARY_PATH variable by running that directly in the shell, I could SSH to my servers to perform my checks. I then added it to the end of my Zenoss user’s .bashrc script.

So far I haven’t seen anything broken, but will certainly report back if I do run into any issues. I’m not entirely sure what the LD_LIBRARY_PATH variable does, but a quick Google search showed 3 results of people saying it was a bad idea to use it. Again, not sure but I give it a big “works for me” :)

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Filed under How-Tos / Tips : Comments (0) : Aug 4th, 2009

SSH (and tunnel) In One Click of a Mouse

I can’t believe I haven’t seen this tool before. Worse yet, I can’t believe how much time I must have wasted SSH’ing to hosts. Tonight I discovered SSHMenu for Gnome.

I’m a systems administrator on a mostly Linux network (but with a few Windows hosts). Given that, I rely on SSH a lot. A lot, as in you probably wouldn’t catch me not SSH’d into something at any moment during my work day.

SSHMenu

SSHMenu

I do find that I tend to SSH into the same machines over and over again as well as have a few ports that I forward through the firewall that are not exposed to the outside of our DMZ. With SSHMenu, I can not only save a set of the machines that I log into often, but I can also pass options like port forwarding and others.

To get SSHMenu, you’re just a sudo apt-get install away:
sudo apt-get install sshmenu-gnome

To enable it, you’ll need to add it to your Gnome panel by right clicking on the panel and going to the “Add to panel..” window.

Add to panel window

Add to panel window

You can then begin adding hosts in the SSHMenu preferences. The program passes the options you include in the hostname field into the SSH utilitiy so you can insert things like usernames and options as you please. For me, I setup my tunnels so I don’t have to type them in all the time. The one that I saved went a little something like this (with hostnames modified to protect the innocent):
user@host.domain.com -L 8888:windowshost.domain.com:3389

With a couple of clicks of a button I can be not only SSH’d in, but have a tunnel setup to connect via my RDP client (for my example).

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Filed under How-Tos / Tips : Comments (4) : Jul 15th, 2009

7 Software Utilities I Need for Real Life

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We as humans have designed software to make our lives easier. My life is so ingrained in software that sometimes I find myself wanting to just type a simple command to make things easier myself. In fact, some days I even know what utilities to use and exactly how I would script common tasks in my life. Here are a few of the utilities I’ve wanted to use for the physical world:

grep – I’d be a rich man if I had a quarter for every time I wished I could do something like this in the physical world: ‘grep -R car_keys /home’. Unfortunately, this would probably allow me to be even more unorganized since I could just search for what I need rather than actually organize things so they are easy to find.

rsync – I’ve always wanted to be able to take a set of knowledge that someone has and just copy it over to me. Using rsync, I could easily transfer all data or a set of data from someone else’s brain to mine. But, alas we couldn’t be that lucky.

Xgrid – Whenever a task is too large for me to comprehend or accomplish in a given amount of time I really wish I could just hand it off automagically like Apple’s Xgrid. Delegating tasks tends to be a pain. You have to transfer the information (which we just discussed) and then give an explanation on how to accomplish the task. Using Xgrid, I could just hand off tasks (this would’ve been useful in college) and get the results back.

snapshots – We’ve all been there. We think “wow, that wasn’t my brightest moment”. It’s times like this where I wish I could just fall back to a point in time. We can make volume snapshots or virtual machine snapshots, mess up a machine beyond repair, and fall back to a previous running state. This would have been especially helpful that time that I tried closing that garage door by putting my fingers between the panels and pulling down. Doh!

rm – The human brain remembers a lot of things (though it seems not the things we want it to). Some days I’d like to be able to just wipe bad memories from my mind using rm.

kill – Don’t worry, I’m not looking to kill anyone. What I really need is a way to kill off processes. You know, when you’re lying in bed at night and you just can’t stop thinking about that latest article on whatan00b.com? Wouldn’t it be nice to just to just kill off the process? I know I need that some days.

SSH – Some days I know exactly what I forgot to do or want to preheat the oven on my way home or just change my laundry while I’m at work. SSH would be perfect for that, but sadly enough, no such luck. (note: The oven thing would actually be possible, though a little bit ridiculous at this point.)

Software running in the human world would definitely be helpful and help me accomplish a lot more in a day. What’s really sad is when I know exactly what command to use.. Now, I need to get back to grepping searching for my keys.

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Filed under Just for Fun : Comments (0) : Sep 22nd, 2008

SSH "Vulnerabilities"

I had to laugh when I read the comments on zdnet’s article on how compromised SSH keys are leading to rootkits in Linux systems. Okay, I’ll admit it. I’m a Linux fan and am going to be partial to defending my pet operating system, but let’s all take a minute to think about this. The first part of the attack happens when an attacker is first able to login to an SSH server with a stolen key. Once the attacker has a shell, they are using a vulnerabilities to install rootkits. Sure, that means there are vulnerabilities once a user has a shell, and I’m not about to say that Linux is impenetrable. But let’s consider what’s happening here. The attackers are using a stolen key. The attackers could just as easily use a stolen password. The same would happen if you opened up remote desktop on your Windows server to the world and gave out your password. Okay, so this was mostly a rant about some comments made, but let’s all take the time and watch what public-facing services are running on our systems. Don’t open up a service on your servers if you don’t plan on logging and auditing the service. All OS’s are vulnerable to attacks due to poor implementation and good grief, be careful with your keys!

I also had to laugh when I went to the CERT article that the zdnet article was about. Right below it, CERT issued a warning about a vulnerability in PowerPoint that allowed remote code execution with escalated privileges if a user opened a crafted file. Wow, talk about irony! Yes, I know that there’s vulnerabilities in software from pretty much every vendor so don’t flame me, but I loved the irony.

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Filed under Tech Trends : Comments (0) : Aug 28th, 2008