Specifications

Memory: 2 GB RAM (4 GB RAM recommended)

Nessus scanning large networks

including audit trails and PDF report

generation

CPU: 1 Dual-core 2GHz Intel CPU (2 dual-core

recommended)

Memory: 3 - 4 GB RAM (8 GB RAM recommended)

30 GB

Nessus can be run under a VMware instance, but if the virtual machine is using Network Address Translation (NAT) to

reach the network, many of Nessus’ vulnerability checks, host enumeration, and operating system identification will be

negatively affected.

As of the Nessus 6.0 release, only 64-bit architectures are supported.

Nessus Unix

Before installing Nessus on Unix or Linux, there are several libraries that are required. Many operating systems install

these by default and typically do not require separate installation:

 zlib

 GNU C Library (i.e., libc)

 Oracle Java or OpenJDK (for PDF reporting only)

Java must be installed on the host before Nessus is installed. If Java is installed afterwards, then Nessus will

need to be reinstalled. Further, the same architecture version must be installed, meaning Nessus 6 will only

recognize a 64-bit installation of Java. Many web browsers are 32-bit, meaning visiting the Java download page

will automatically provide the 32-bit version of Java. You may need to manually download the 64-bit version.

Nessus does not support installing to a directory or location via a symlink. If required disk space exists outside

of the /opt file system, mount the desired target directory using “mount --bind <olddir> <newdir>”.

Make sure that the file system is automatically mounted on reboot by editing the /etc/fstab file accordingly.

Nessus Windows

For increased performance and scan reliability, it is highly recommended that Nessus Windows be installed on a server

product from the Microsoft Windows family such as Windows Server 2008 R2. For more information on this issue, please

see the “Nessus Windows Troubleshooting” section.

Deployment Options

When deploying Nessus, knowledge of routing, filters, and firewall policies is often helpful. It is recommended that Nessus be

deployed so that it has good IP connectivity to the networks it is scanning. Deploying behind a NAT device is not desirable

unless it is scanning the internal network. Any time a vulnerability scan flows through a NAT device or application proxy of

some sort, the check can be distorted and a false positive or negative can result. In addition, if the system running Nessus

has personal or desktop firewalls in place, these tools can drastically limit the effectiveness of a remote vulnerability scan.

Host-based firewalls can interfere with network vulnerability scanning. Depending on your firewall’s

configuration, it may prevent, distort, or hide the probes of a Nessus scan.