What is nessus?

I know that this may be this may be quite annoying for some experts ... hopefully annoying enough to flame me. But I have heard too much about nessus. This thing comes along with many Linux distros. But after all what is nessus? Google and other searches tell it is a network vulnerability scanner. However I see some people tell that nessus is a DATA recovery software. While some say that it runs on *nix boxes but some say that runs even on Windows.

So is nessus a Network vulnerabilty scanner or Data recovery solution or both?

What OSes does it run on? Does it run on only *nix or Windows or both or even on others like Mac?

Thanks in advance.

Nessus : Premier UNIX vulnerability assessment tool
Nessus is the best free network vulnerability scanner available, and the best to run on UNIX at any price. It is constantly updated, with more than 11,000 plugins for the free (but registration and EULA-acceptance required) feed. Key features include remote and local (authenticated) security checks, a client/server architecture with a GTK graphical interface, and an embedded scripting language for writing your own plugins or understanding the existing ones. Nessus 3 is now closed source, but is still free-of-cost unless you want the very newest plugins. Also, run on windows xp. This was copied and pasted from www.insecure.org
and don't forget about

http://www.nessus.org/

In other words, it's not a data recovery tool. It's a vulnerability scanner that runs on UNIX and W32. In addition to Nessus, Tenable makes additional compliment software.

For more, see: http://www.tenablesecurity.com

--TH13

Nessus 3 is available for the following platforms :
- Linux : Fedora FC5 & 6, Red Hat Enterprise 3 & 4, SuSE 9.3 & 10, Debian 3.1 (i386)
- FreeBSD : FreeBSD 5 & 6 (i386)
- Solaris : Solaris 9 & 10 (sparc)
- Mac OS X : Mac OS X 10.4 (intel & ppc)
- Windows : Windows 2000, XP and 2003 (32 bits)

Thanks a lot to all of you. I understood the fact. Now can someone tell me if it fine to use it for scanning my home network with it?

Will using it to scan external IPs be against Law? I wanted to use it to scan the external IPs.

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Thanks a lot to all of you. I understood the fact. Now can someone tell me if it fine to use it for scanning my home network with it?

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Nessus 3.0.5 would be perfect for you to scan your LAN also help to find any holes, open ports detailed technical info about each warning excellent too indeed. As a matter of fact I scanned a box on mmy WLAN last night.

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Will using it to scan external IPs be against Law? I wanted to use it to scan the external IPs.

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Honestly, I don't know I havent read the EULA IM sure it's all covered in their. As far as legal action yes you could get in trouble for scanning remote machines espically with an application like nessus. I personally wouldnt just scan random host(s) with an application like nessus. To noisy. Try an app like nmap from www.insecure.org

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I personally wouldnt just scan random host(s) with an application like nessus. To noisy. Try an app like nmap from www.insecure.org

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NMAP scans can be seen just like a jumbo jet coming out of the sky if you don't configure the scan properly. Have a look at some of the tutorials on the site for step by step instructions on how to use NMAP effectively.

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Will using it to scan external IPs be against Law? I wanted to use it to scan the external IPs.

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It depends what you scan, which country the target host/network resides and what laws you break in between. Best practice is to assume that it is illegal unless you've been given permission to scan it. Insecure.org has a dummy server out on the net that you can freely scan. Visit the site for details.

Scanning from behind a SOHO NAT router (like Linksys, etc.) out to external IPs is a verrrrry bad idea. You will consume all the memory used for the connection table and your router will lock up tight.

--TH13

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NMAP scans can be seen just like a jumbo jet coming out of the sky if you don't configure the scan properly

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Exactly, very true indeed. However, the reason I recommend nmap because with the right options you can make it more stealth/less noticable than you would with Nessus 3.

I have used NMAP in past and know very well that how problematic it can become. in some cases it can be too late too. Anyway i will check the tutorial section for that.

thank you all.

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Will using it to scan external IPs be against Law? I wanted to use it to scan the external IPs.

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Why on earth would you want to scan external IPs ? Thats rude!