Use SSH to secure remote admin

By Peter Parsons, TechRepublic, 17 March, 2003 11:56

ANALYSIS

The TightVNC enhancement to the original VNC freeware application from AT&T research labs in the UK adds secure communication channels for remote administration sessions. TightVNC secures these communication channels using Secure Shell (SSH). Unix and Linux administrators have used SSH for years, and now Windows administrators can take advantage of it using TightVNC. To demonstrate how it works, I'll show you how to implement TightVNC and SSH on a Windows NT server. You can use the same logic to secure communications on other TightVNC supported systems. First though, a few words on SSH. Not only does SSH encrypt authentication parameters, it also encrypts all the session traffic. SSH is meant to replace insecure session protocols such as telnet, rsh, and rlogin. It allows the secure movement of data and files across insecure channels, (e.g., the Internet). In the case of TightVNC, SSH can secure remote administration commands. SSH is in widespread use across 60 or more countries. SSH comes in two flavors, SSH1 and SSH2. Both encrypt different parts of a packet. Both are different protocols -- SSH2 is basically a rewrite of SSH1 with improvements in security, portability, and performance. SSH1 is no longer under development, but SSH2 is still being developed. SSH on NT In terms of licensing, noncommercial use of SSH is generally free. But if you're going to use SSH commercially, you should buy the software. There are various vendors including SSH Communications Security and VanDyke Software. Although it's outside of the scope of this article, installing an SSH daemon onto an NT box is pretty straightforward -- you can refer to the vendor's documentation for this. Once you have the SSH NT server host up and running, you'll also need an SSH client on the administration workstation you'll use to access the remote sites. Securing the link Start off by installing the TightVNC server on your target server or workstation and the TightVNC client on your administration workstation. For details about how to do this, see the article "Remote administration -- with security!" Test the communications on an unsecured channel between the server and workstation to make sure that VNC works properly. After you've confirmed that everything works, you must make a change to TightVNC's Advanced Properties. Double-click the TightVNC icon in the system tray. When the dialog box opens, select the Advanced button. In the Advanced Properties dialog box, be sure to check the Allow Loopback Connections and Allow Only Loopback Connections check boxes, as shown in Figure A. This ensures that TightVNC works through only the SSH secure pipe.

Figure A

Set loopback connections to allow TightVNC to use secure channels.

Once you're up and running with TightVNC in loopback mode, and both the SSH daemon and client are installed, you can initiate a secure session. When you do this, a dummy server will be created on your client machine that listens on the VNC port and moves all connections to that port into the SSH tunnel. The SSH tunnel in turn transports the connections to the remote server. Because you've selected the loopback mode above, TightVNC will think that the connection is a local one and allow a secure session to be built. Your remote admin traffic will then be secure. Final thoughts SSH can be used through firewalls, and you can also use it to protect FTP, POP, and IMAP sessions going through a firewall. Most SSH sessions through a firewall use port 22, but you can change this to go through another open port on the firewall, such as SSL port 443, which is usually open anyway.

For a weekly round-up of the enterprise IT news, sign up for the Enterprise newsletter. Tell us what you think in the Enterprise Mailroom.

Post your comment

In order to post a comment you need to be registered and logged in.

You can also log in with Facebook. Log in or create your ZDNet UK account below

By signing up for this service, you indicate that you agree to our Terms and Conditions and have read and understood our Privacy Policy. Questions about membership? Find the answers in the Community FAQ

ZDNet UK Live

Nice review and very informative. One thing I'd like to add (in reply to whs001's 1st question), the main reason to have the same interface from...

55 minutes ago by GrueMaster on A tale of two distros: Ubuntu and Linux Mint

I'be been using Mint 12 since the RC came out, and I am far more happy with the Cinnamon, the Mate, and, yes (with extensions), theGnome 3...

2 hours ago by Frederick Wrigley via Facebook on A tale of two distros: Ubuntu and Linux Mint

Excellent article. One small correction, though--although a fresh installation of Linux Mint 12 will, indeed, provide the user with a version of...

2 hours ago by bdantas on A tale of two distros: Ubuntu and Linux Mint

In related news, the ISPs club together to get the members of the Home Affairs Select Committee (ya goofed on that part, ZDNet UK) copies of "The...

3 hours ago by Alan Ralph via Facebook on MPs urge ISPs to take down terrorist material

In related news, the ISPs club together to get the members of the Home Affairs Select Committee (ya goofed on that part, ZDNet UK) copies of "The...

3 hours ago by Alan Ralph via Facebook on MPs urge ISPs to take down terrorist material

For Gnome 2 die-hards, it is possible to add icons to the bottom panel (or top top panel, if you prefer) which provide the exact Gnome 2...

4 hours ago by Moley on A tale of two distros: Ubuntu and Linux Mint

Your comments would seem pretty naive and immature. Your 'solution' appears to be, "gee, let's all just give in to the hackers and give them...

4 hours ago by ramwellian on Cloud computing security: no more oxymoron?

"Interesting thought ... If you installed Win7 as a dual boot on a machine that previously only had Linux, and it wrecked your Linux installation,...

4 hours ago by BugStalker on Windows 7 Declares War on GRUB

This is an excellent summary of Ubuntu and Mint and the interface differences between them. Most such articles take a very partisan position for...

4 hours ago by whs001 on A tale of two distros: Ubuntu and Linux Mint

@ewallace. Not so clear. Anyone can obtain the text, for example from here http://www.ustr.gov/webfm_send/2379. I support ACTA so long as it and...

5 hours ago by Moley on ACTA: Facts, misconceptions and questions

I think WinRT is fantastic. I just wish it was an option for people that didn't want to go through Microsoft's App Store with its attendant...

8 hours ago by 45283 on Why Windows 8 needs architectural hygiene for WOA

Nine people? £30m? Who's back pocket is that lot going in? And IF they say it is for new buildings, what about all the ones the government has...

9 hours ago by Burn-IT on Police set to launch three £30m e-crime hubs

Just to be clear, nobody knows what is in the text of ACTA, here is a photograph of the text of ACTA http://twitpic.com/8h9iju as submitted to the...

9 hours ago by ewallace on ACTA: Facts, misconceptions and questions

Unfortunately main issue is that ASUS is refusing to accept that they make some mistake on this version of asus Transformer prime. 1 - GPS sensor...

10 hours ago by fgvrg56 on Asus Eee Pad Transformer Prime Wi-Fi & GPS problems?

@Marcus A fair question. Just talked with Archos which said it was working on an announcement for next week....

11 hours ago by Ben Woods on Archos confirms G9 Ice Cream Sandwich update schedule

Any update on this, considering the claimed "first week of February"?

12 hours ago by Marcus Karlsson via Facebook on Archos confirms G9 Ice Cream Sandwich update schedule

Bill Goodrich : Just as al_langevin pointed out, with Windows Server 2008 there is no Services for Macintosh anymore. It's gone, not available....

21 hours ago by apexwm on Windows Server 2008 drops the ball for Mac compatibility

Replying to an old topic that I'm currently facing with my CEO (who is on a Mac). Our servers are primarily Windows Servers, office is about...

1 day ago by txtrainguy on Windows Server 2008 drops the ball for Mac compatibility

Sure, that makes perfect sense. Pay wrong-doers money and thank them for breaching your security and pointing out your flaws, that would surely...

1 day ago by k0tcs3 on US indicts Romanian over NASA climate change hack

I think he's referring specifically to Android apps, as Apple do regulate their App Store, but Google seem to let any old crap onto the Android store!

1 day ago by Random_Error on RIM: BlackBerry will keep 'garbage' apps out of store

Featured white papers

Latest jobs

Use SSH to secure remote admin

Daily Newsletters

Topics

Related stories

Vulnerable OpenSSH

Secure apps to stop network attacks

Remote administration -- with security!

Ten flawed products that derail productivity

Adobe relents on CS6 upgrade charges

Post your comment

ZDNet UK Live

Latest in Desktop Apps

Ten flawed products that derail productivity

Adobe relents on CS6 upgrade charges

Featured white papers

Latest jobs

Test Analyst - Business Intelligence /Data Warehousing

Test Analyst - Business Intelligence /Data Warehousing

Technical MI Manager - 50-60k - Leeds

Inside ZDNet UK

A tale of two distros: Ubuntu and Linux Mint

2012 Predictions: VCE FastPath, VI SAN Probe & Hadoop

BlackBerry Bold 9790

Case study: How cloud enables growth

Ten factors that make Ubuntu 11.10 a hit

Toshiba Portégé Z830-10P Review

BT's archive: Pictures from the vault

News & Analysis

Reviews

Blogs

Resources

About Us

Member Services

Special Features

Advertising Features

ZDNet UK / News and Analysis / Workspace IT / Desktop Apps

Use SSH to secure remote admin

Daily Newsletters

Topics

Related stories

Post your comment

Get ZDNet UK's daily newsletter

Enter your email address to sign up

ZDNet UK Live

Latest in Desktop Apps

Featured white papers

Latest jobs

Inside ZDNet UK

Resources

About Us

Member Services

Special Features

Advertising Features