Network

Grafana is an open source metric analytics & visualization tool which can help us to monitor the system with a nice Dashboard. Installing Grafana Grafana is available in the APT packages repository, however it could not be the latest version, so we’ll use the official Grafana repository. First, it is needed to install the software needed before install Grafana. sudo apt install -y apt-transport-https sudo apt install -y software-properties-common wget ...

In my diary activities usually I have to check the connectivity between two hosts. In this article I will explain which is the method I use to do it. ...

iPerf is a tool designed to test the bandwidth between two hosts using the network. It is a really simple, powerful CLI which allows generating traffic / load TCP or UDP between 2 hosts. You could use to measure the maximum bandwidth of the network between a client and a server. It can be used to do stress tests of the Ethernet, Wi-Fi or of your ISP. iPerf2 vs iPerf3, what is the difference? There has been different versions of this tool in the last years. It started ttcp from the National Laboratory for Applied Network Research (NLANR), and then it was developed iPerf (iPerf 2). iPerf3 is a new implementation from scratch, with the goal of a smaller, simpler code base, and a library version of the functionality that can be used in other programs. The functionality between iPerf2 and iPerf3 are mostly compatible, however you should know they use different ports by default. In iPerf2, the default port is 5001, and in iPerf3, 5201. ...

Speedtest is a great tool to verify the status of your internet connection. With it you could check if your ISP (Internet Service Provider) is providing you the speed you have contracted. Normally you would like to use the Speedtest Website version, but here I am going to explain how to use from a Linux Command Line or Linux Terminal. This tutorial is based of the use of the speedtest-cli GitHub Project. ...

The Linux command line is a great tool. Today I’ll like to share a method to get Geographical IP information with one command, using curl and the tool of ipinfo.io. It is as easy to use this command: $ curl ipinfo.io/<IP Address> Here you have an example: You will have these parameters: IP City Region Country Loc (Coordinates) Org Postal Timezone If you want to get information about the Public IP Address you use to go to The Internet, you could execute the command this way: ...

By default, Ubuntu desktop installation will provide DNS resolving configured, however in Ubuntu server installation avahi-daemon (or mdnsresponder) is needed to be installed to provide local LAN DNS resolution. In my case, i found the error “Temporary failure in name resolution” when I tried to resolve a machine of my LAN from Ubuntu. yvoictra@zoar:~$ ping erie.local ping: erie.local: Temporary failure in name resolution To solve this issue, there is no need to install a DNS server in the LAN. We can use the mDNS (Multicast Domain Name System) protocol. This protocol is used to resolve host names in a small network (LAN). The mDNS service can be contacted using UDP queries over port 5353. The mDNS protocol is published as RFC6762 and implemented by the Apple Bonjour and avahi-daemon services. ...

Monitoring network traffic or bandwitdh usage is a must in a SysAdmin tasks. There are many differents tools to manage this monitoring, but one of my favorites is vnStat. The main advantage of this tool is the simplicity of its usage. Installation With Ubuntu, the way to install this tool is with apt. sudo apt install vnstat First steps Once installed, it is important to know which interfaces are going to be monitoried. For this, you can use next command ...

First step is to check the status of the interfaces. For this, we will use the net-tools package. sudo apt install net-tools Then, we can see the interfaces status ifconfig -a In my case, I have this status of my interface wlan0: ubuntu@ubuntu:~$ ifconfig -a wlan0 wlan0: flags=4098<BROADCAST,MULTICAST> mtu 1500 ether dc:a6:32:6c:xx:xx txqueuelen 1000 (Ethernet) RX packets 0 bytes 0 (0.0 B) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 0 bytes 0 (0.0 B) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 ...