How to Test an SMTP Server with Telnet command line How to test SMTP and IMAP servers using the telnet command-line Linux Networking Windows
Nginx Location Priority Manual The location directive within NGINX server block allows to route request to correct location within the file system. The directive is used to tell NGINX where to look for a resource by including files and folders while matching a location block against an URL. In this tutorial, we will look at NGINX location directives in details. Linux Networking Web Servers
Test IMAP with telnet IMAP connection theory The first thing any client needs to do is to make a connection to the remote imap server on a specific port. These ports can vary, but default port for plaintext imap service is 143 , and for encrypted (SSL/TLS) imap service is default port 993 . You can use for plaintext imap connection a telnet utility, or for encrypted imap service you can use openssl s_client command. Networking Linux
Arpwatch - monitor mac addresses change Arpwatch Arpwatch is an open source computer software program that helps you to monitor Ethernet traffic activity (like Changing IP and MAC Addresses) on your network and maintains a database of ethernet/ip address pairings. It produces a log of noticed pairing of IP and MAC addresses information along with a timestamps, so you can carefully watch when the pairing activity appeared on the network. It also has the option to send reports via email to an network administrator when a pairing added or changed. Networking Linux Security
Installation of LTE modem into Turris Omnia router Assembly You need a cross-point screwdriver for the assembly. Step 1 Remove the 6 screws using the cross-point screwdriver. Then carefully remove the upper cover of the router. Make sure that thermal conductive rubber will remain sticked to the CPU cooler while removing the cover. If it detaches put it back on the cooler. Step 2 Insert the SIM card into the SIM slot located under one of the mPCIe slots. Networking
How To Refresh an Access Token Using Decorators When I was creating a one script, which uses JWT for authentication, I began to run into challenges with longer scripts that extended beyond the expiration of a single JWT. To elegantly solve this, I used decorators to check the token’s expiration and request a new token if necessary. This article goes over the framework I set up so that you can apply a similar mechanism in your own scripts. Python Development Networking
How use Python retry decorator function with API An ever-increasing proportion of a typical company’s infrastructure is moving to the cloud. More companies are shifting towards a micro-service approach. These paradigm shifts away from local to cloud-based means that you probably also have faced a situation where you had to pull data from somewhere or write data somewhere that is not your local computer. On a small scale, there rarely are problems around that. If some extraction or writeback fails, you would typically notice that and would be able to remedy the mistake. Python Development Networking
Active and Passive FTP Simplified - Understanding FTP Ports Active and Passive FTP Simplified - Understanding FTP Ports If a client encounters problems when connecting to your FTP server , one of the first things you might want to check is your FTP data transfer mode . Depending on certain network configurations, this mode should be set to either active or passive. In this post, you’ll understand the salient points of active and passive FTP and learn how to avoid connectivity issues associated with them. Networking Security
OCSP Stapling on Nginx and Apache webserver To understand OCSP stapling, it is necessary to understand OCSP, the Online Certificate Status Protocol. OCSP is a protocol for determining whether a certificate is revoked (for instance, becau se its private key was compromised). Every time a browser connects to an HTTPS website, it contacts the OCSP responder specified in the SSL certificate, and asks if the certificate is revoked. If the respond er replies that the certificate is revoked, the browser blocks the page from loading. Web Servers Networking Security
ProFTPd Server with virtual users and in SFTP mode How to configure proftpd server with virtual users and with sftp mode. Debian Linux Networking Security
nftables geoip - continents ip In the previous articles, we showed how to perform packet marking in nftables based on geoip source ip addresses and also how to log traffic to external files . Today we will show how to mark packets based on which continent they come from. The principle is that we first mark packets based on the source IP address so that we know which countries they are coming from. And then we'll find out which continent the state is on. Linux Security Networking
nftables and GeoIP How to Block IPs from Countries or Continets using NfTables Geoip script We'll learn how we can block traffic originated from specific country or continent IPs using GeoIP database and linux nftables . This article describes the configuration for debian linux distros. nftables is the new packet classification framework that intends to replaces the existing {ip,ip6,arp,eb}_tables infrastructure. In a nutshell: It is available in Linux kernels >= 3.13 It comes with a new command line utility nft whose syntax is different to iptables. Linux Security Networking
