Linux Command Line Operations

You must run all commands with root privileges.

Start, Stop, or Restart NNM

Action	Command to Manage NNM
Start	# service nnm start then # ps aux|grep nnm
Stop	# service nnm stop
Restart	# service nnm restart

Once a day, as scheduled, if Tenable.sc has received new NNM plugins from Tenable®, it installs them in the NNM plugin directory. NNM detects the change, automatically reloads, and begins using the new plugins.

Real-time NNM data is communicated to the configured LCE server or Syslog server(s) in real-time.

Configure HugePages

Before You Begin

These steps assume that your system meets the System Requirements necessary for running NNM in High Performance mode.

To configure HugePages:

1. Ensure your HugePages settings are correct by using the following command:

   # grep Huge /proc/meminfo

   AnonHugePages: 0kB

   HugePages_Total: 1024

   HugePages_Free: 1024

   HugePages_Rsvd: 0

   HugePages_Surp: 0

   Hugepagesize: 2048kB

   The Hugepagesize parameter is set to 2048 kB by default, but this option is configurable. NNM requires a minimum of 1024 HugePages that are at least 2048 kB in size.

   Note: In some cases, the HugePages_Free parameter may be set to 0, however, this does not necessarily indicate insufficient HugePage memory.

2. Reserve a certain amount of memory to be used as HugePages by using the following command to update the kernel parameter manually:

   /bin/echo 1024 > /sys/devices/system/node/node0/hugepages/hugepages-2048kB/nr_hugepages

   The number of HugePages reserved by the kernel changes to 1024, and HugePages become available.

   Note: If the kernel does not have enough memory available to satisfy this request, the command may fail without notifying the user. After running this command, the HugePages configuration should be checked again using the command in step 1.

3. To ensure that your HugePages configuration persists across system reboots, refer to the following section that corresponds to your Linux kernel version.

   CentOS 6

   Update the persistent kernel configuration files using one of the following commands:

   In the /etc/sysctl.conf file, add the vm.nr_hugepages=1024 parameter and reload the kernel configuration with the sysctl -p command. Alternatively, you can reboot the system.

   -or-

   In the /etc/grub.conf file, on the kernel startup line, add the hugepages=1024 parameter and reboot the system.

   CentOS 7, 8

   Update the persistent kernel configuration files using one of the following commands:

   In the /etc/sysctl.conf file, add the vm.nr_hugepages=1024 parameter and reload the kernel configuration with the sysctl -p command. Alternatively, you can reboot the system.

   -or-

   In the /etc/sysconfig/grub file, on the kernel startup command (GRUB_CMDLINE_LINUX), add the hugepages=1024 parameter. Reload the kernel configuration with the grub2-mkconfig -o /etc/grub2 command and reboot the system.

4. Connect the file system to the HugePages subsystem using the following steps:

   1. Execute the /bin/mkdir -p /mnt/nnm_huge command.

   2. Execute the /bin/mount -t hugetlbfs nodev /mnt/nnm_huge command.

   3. Additionally, open the /etc/fstab file location and add the following record:

      nodev /mnt/nnm_huge hugetlbfs rw 0 0

File Locations

NNM installs its files in the following locations:

Path	Purpose
/opt/nnm	Base directory.
/opt/nnm/bin	Location of the NNM and NNM Proxy executables, plus several helper tools for the NNM Proxy daemon.
/opt/nnm/docs	Contains the software license agreement for NNM.
/opt/nnm/var	Contains the folders for NNM and the NNM-Proxy.
/opt/nnm/var/nnm	Contains plugins, discovered vulnerabilities, log files, keys, and other miscellaneous items.
db	Contains the database files related to the configuration, reports, and users for NNM.
kb	Stores the NNM knowledge base, if used.
logs	Contains NNM logs.
plugins	Contains the NNM plugins delivered via Tenable.sc, Tenable.io, the NNM Feed, or updated via the command line or web interface if NNM is running in Offline mode. Note: If Tenable.sc is used to manage the plugins, do not change this path from the default /opt/nnm/var/nnm.
nnm-services	A file NNM uses to map service names to ports. This file may be edited by the user. Plugin updates do not overwrite modifications to the file.
reports	Contains reports generated by NNM. This folder contains the .nessus file generated by default.
scripts	Contains the files for the NNM Web server.
ssl	Contains SSL certificates used by the proxy and web server for the SSL connection between itself and Tenable.sc or the web browser.
users	Contains folders for user files and reports.
www	Contains the files for the NNM web front-end.
/opt/nnm/var/nnm-proxy	Parent folder for files used/created by the NNM proxy.
logs	Contains the NNM proxy and NNM proxy service logs.