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Top 10 open source networking tools for administrators

Before the world became flat, the world became highly networked. Boundaries around locations and time zones blurred. The world today is highly productive and efficient but only if the network link is functioning between locations. As networks have become bigger and busier, monitoring has become complex and critical. Cloud services, web meetings, video, VoIP, BYOD — you name it — have further added stress on your network. Network monitoring in the cloud environment is particularly challenging because container environments are continually evolving and the applications built are equally dynamic and may scale or disappear entirely at any given point. Network performance monitoring can consist of monitoring performance of websites, Internet servers, the various links and, route analytics. Response time, availability, and uptime are important metrics to monitor for any network. For example, status request failures, timeouts, and connection failure to retrieve a file or message indicate network failure that triggers an action in the monitoring system for troubleshooting. Here is a list of open source networking tools for administrators to keep handy.

Nagios Core

Nagios Core is an absolute favorite open source tool with network administrators and developers and has a very vibrant community. Nagios is straightforward and highly scalable, which makes it an effective tool for network, application, and server monitoring in larger, enterprise-class environments. The visualization capability of Nagios is an extremely popular feature, which gives a centralized view of the entire monitored IT infrastructure. Nagios is very powerful, scalable, and flexible. It can be scaled up to monitor up to 100,000 hosts. The cool failover capability ensures nonstop monitoring of critical IT infrastructure components. It can be easily integrated with third-party tools such as Check_mk and Vigilo NMS.for additional functionalities. Specific tools can be added for specific functionalities. Nagios provides monitoring support for protocols, applications, Internet servers, websites, links, and much more.

And if the above features are not enough, you can always graduate to Nagios XI.


Network implementation in Kubernetes is not easy. That’s precisely where the usefulness of a good tool like Flannel lies. Flannel is a layer 3 virtual network designed for Kubernetes. Each host in a Flannel network runs a binary agent called flannel. It allocates each host a subnet lease out of a larger, preconfigured address space acting as IP address pool. Containers then establish connections directly using IP addresses allocated to them. Network configuration and subnet information are stored either in the Kubernetes API or etcd. Packets are forwarded using one of several backends encapsulating mechanisms including Virtual Extensible LAN.


SolarWinds has a host of open source tools. The toolkit of Solaris for Network Administrators provides the entire range of tools required for network monitoring, diagnostics, and network discovery tools. SolaReal-Time NetFlow Analyzer is excellent for troubleshooting network performance. It easily identifies users, applications, and devices that are clogging the network. SolarWinds WAN Killer tests network performance by testing network traffic and load balancing. SolarWinds TFTP Server is a multithreaded, reliable TFTP Server. SolarWinds SFTP/SCP Server is another commonly used tool from the Solaris toolkit to upload and download executable images for routers and switches.

Weave Net

Weave Net helps to create a secure, encrypted network with container-to-container access control rules, easily and quickly, be it on-premises or in the cloud. It creates a virtual network connecting Docker containers across multiple hosts and offers service discovery, policy management, and fault tolerance. It sets up subsystems that provide a distributed virtual firewall system and routes around network failures. Additionally, Weave Net can encrypt all traffic between hosts. Weave Net is known for its tolerance ability and its resilience to recover from network partitions. It is built on a decentralized architecture, and routes VXLAN packets in the kernel instead of user space, thus reducing dependency on highly available storage.

Project Calico

Calico is built on proven IP routing technology to connect containers, making it possible to scale cloud securely to heavy workloads. Calico is focused on network policy which has a micro-firewall for every workload. DevOps staff can easily define whether a connection is allowed or not. A distributed algorithm dynamically calculates and analyzes the rules required for each node in the cluster. As a result, any possible anomaly is detected well before it can cause any significant damage. Calico comes with a variety of plugins for Kubernetes, Mesos, Docker, OpenStack, and various other vendor derivatives.


Istio is a platform-independent service mesh that provides the fundamentals required to run a distributed microservice architecture. Network operators have to manage multicloud and hybrid deployments as organizations adopt cloud platforms. Istio provides a seamless, uniform way to secure and connect microservices, simplifying deployments. Developers are also free to focus on application level security. Istio is a very popular choice for self-contained microservices built on Kubernetes. For enterprise-wide control, Istio can be used with tools such as Glasnostic.


Canal is a unified networking solution to integrate the best of Flannel and Calico. It combines Calico’s fine-grained network policy capabilities with Flannel’s connectivity elements. Canal acts as a deployment tool for installing and configuring both Flannel and Calico. As developers focus on adding features to both projects, the result is literally the best of both worlds — an open source networking fabric with built-in policy management.

Angry IP Scanner

Angry IP Scanner is a very popular open-source, multithreaded IP address and port scanner used by millions — 29 million to be precise. It’s a standard tool for network administrators like Wireshark. Angry Scanner scans IP addresses and ports on local networks as well as on the internet. It first rapidly pings (hence the name) and then troubleshoots resolving hostnames, gathering MAC addresses, operating systems, etc. Output can be saved as CSV, TXT or XML. It runs on Linux, Windows, and Mac OS X.


Zabbix is an enterprise-class open source networking tool solution for monitoring servers, virtual machines, and cloud services. Zabbix provides monitoring for network utilization, CPU load, and storage. Simple checks are enough to review the availability and responsiveness of standard services without installing any software on the host. Users can view their IT environment using customizable dashboards in the GUI. Zabbix can be deployed for agent-based and agentless monitoring. It monitors operations on Linux, HP Unix, Mac OS X, Solaris, and other operating systems.

Wireshark / Tshark

No list of open source networking tools is complete without the mention of Wireshark, often referred to as one of the best open source networking tools. Wireshark is a network analyzer — your microscope and magnifying lens for all network troubleshooting. It has the ability to clearly inspect hundreds of protocols and can provide both live and offline analysis. Wireshark runs on multiple platforms: Windows, Linux, Solaris, BSD, and many others. Its visualization capability makes analysis easy to understand. The output of troubleshooting can be exported to multiple formats including XML, CSV, or text.

Networking used to be simple back in the day of client-server enterprise applications. However, with the advancement in software, monitoring your network has had to evolve alongside the rest of the application stack. Whether you have a mix of legacy and modern apps or are a startup that runs only cloud-native apps, networking is an important part of your applications’ success. Fortunately, there is a wide range of open source networking tools to suit every need. And the best part is that because these cutting-edge tools are open source, each has a vibrant community of users to give you support and ideas.

Images: Pixabay

Twain Taylor

My interests lie in DevOps, IoT, and cloud applications. I began my career in tech B2B marketing at Google India, after which I headed marketing for multiple startups. Today, I consult with companies in The Valley on their content marketing initiatives, and write for tech journals.

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Twain Taylor

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