Lab Network Monitoring

Design Overview

The goal is to implement a system for capturing and analyzing laboratory network traffic. Data collected includes full packet capture (PCAP), flow summary data (NetFlow), log files for key network services, and protocol specific data. The router’s built in tool is used to capture a livestream of PCAP and NetFlow data. Moloch is used to analyze PCAP data, SOF-ELK is used to analyze NetFlow and log files data, and Ntopng is used for a real-time view of NetFlow traffic.


Tool Purpose Data Source Link Logo Real-Time Monitoring External Probes HTTPS Measurements - Public
Site24x7 Logo Real-Time Monitoring External Probes HTTPS Measurements - Public
RIPE Atlas Logo Real-Time Monitoring External Probes Ping Measurements - Public
RIPE Atlas Logo Real-Time Monitoring External Probes Traceroute Measurements - Public
Moloch Logo Forensics & Analysis Full Packet Capture Moloch - Lab network/VPN only
SOF-ELK Logo Forensics & Analysis NetFlow SOF-ELK - Lab network/VPN only
ntopng logo Real-Time Monitoring NetFlow Ntopng - Lab network/VPN only

Data Capture Interface

Network Design
Figure 1: Laboratory Network Design

Figure 1 shows the laboratory network design. The quarantine network and public network will be monitored using the quarantine bridge interface (vlan20.bridge) and public bridge interface (public.bridge). We used the Mikrotik CCR1009 router’s built in tool for capturing and sending PCAP and NetFlow data.

ESXi Virtual Machines

We use three virtual machine ESXi host that are connected to the instructor VLAN (over the SFP+ interface). The first virtual machine runs Moloch assigned to IP address with port 80 redirected to 8005, listening on udp port 37008 for PCAP data from the router. The second virtual machine runs SOF-ELK assigned to IP address with port 80 redirected to 5601, listening on udp port 9995 for NetFlow (v5) data from the router. The third virtual machine runs Ntopng assigned to IP address, listening on port 2055 for NetFlow (v9) data from the router.

Analysis Tools


Moloch is an open source, large scale, full packet capturing, indexing, and database system. Moloch is designed to listen for packets directly from a network interface. However, the 'network tap' we are using (MainRouter) is a separate device, and using a SPAN/MIRROR port was not feasible. As an alternative, the router sends packets to the Moloch server using the TaZmen Sniffer Protocol (TZSP). A small program on the Moloch server (tazman-listener) receives the TaZmen stream and writes out the original packets to PCAP files in /data/moloch/raw. A Moloch Capture process then monitors that folder, and reads in the packets whenever that PCAP file closes (currently every 10k packets). The backend database is ElasticSearch, and the web interface is provided by Moloch Viewer.



Figure 2
Figure 2: Session Dashboard

Figure 3
Figure 3: SPI View Dashboard

Figure 4
Figure 4: SPI Graph Dashboard

Figure 5
Figure 5: SPI Connection Dashboard

Figure 6
Figure 6: Stats Dashboard


SOF-ELK uses Elasticsearch, Logstash, and Kibana to organize and display NetFlow and network log files data. Elasticsearch is a search engine that provides a distributed, multitenant-capable full-text search with an HTTP web interface and schema-free JSON documents. Logstash provides an input stream to Elastic for storage and search. Kibana is used to access and display the data for visualizations, using graphs and dashboards, through a web interface.

NetFlow Dashboard:

Figure 7: NetFlow Dashboard for Bytes, Flows, and Packets by Protocol, and Statistics Summary

NetFlow Statistics Summary
Figure 8: NetFlow Dashboards for Statistics by Source and Destination IP, Map of Traffic to Source and Destination, and Volume by Source and Destination Port

Netflow Bytes by Protocol
Figure 9: NetFlow Dashboard for Statistics by Explorer, Statistics by Source and Destination AS, and Discovery


Ntopng provides a real-time summary of lab network traffic obtained from NetFlow records.

Ntopng Dashboard
Figure 10: Ntopng Dashboard

Ntopng Active Flows
Figure 11: Ntopng Active Flows

Ntopng Host Historical Summary
Figure 12: Ntopng Host Historical Summary