SPF macros explained Learn everything you need to know about SPF macros to take better control over your SPF records. And one example how resolve spf macro with dns queries. Networking Security
Set up DMARC (verification) for Postfix on Debian server This tutorial will be showing you how to set up OpenDMARC with Postfix SMTP server on Debian/Ubuntu server to block email spoofing and spam. Security Networking
Configure OpenDKIM with Postfix on Debian What are opendkim signing criteria? And how Configure OpenDKIM with Postfix on Debian? Our goal is configure OpenDKIM to sign emails for multiple domains. Linux Debian Security Networking
VLANS One of the technologies used to improve network performance is the separation of large broadcast domains into smaller ones. This article describes how to configure, manage, and troubleshoot VLANs and VLAN trunks. It will also explore security considerations and strategies related to VLANs and trunks, and best practices for VLAN design. Networking
MAC Address Complete Guide MAC addresses play a crucial role in the data link layer (Layer 2) of the Open Systems Interconnection (OSI) model. MAC addresses are used to send Ethernet frames between two stations in the same local area network. Each station has a unique MAC address that is used to identify who is the sender (source mac address) and who the receiver (destination mac address) is. Networking
Linux TCP keepalive TCP keepalive settings play a crucial role in network performance and resource management. By following the best practices and adjusting the settings to suit your specific needs, you can optimize your system’s ability to detect and clean up stale network connections while maintaining optimal performance. Networking Linux
IP Packet Structure IPv4 is the most widely used version of the Internet Protocol on the internet, and it is responsible for the rules of data transmission between the computing machines. Networking
Ethernet Frame Header In computer networking, an Ethernet frame is a data link layer protocol data unit and uses the underlying Ethernet physical layer transport mechanisms. In other words, a data unit on an Ethernet link transports an Ethernet frame as its payload. Networking
Maximum Transmission Unit (MTU) and the Maximum Segment Size (MSS) The maximum segment size (MSS) is a parameter of the Options field of the TCP header that specifies the largest amount of data, specified in bytes, that a computer or communications device can receive in a single TCP segment. It does not count the TCP header or the IP header. Networking
A Simple Introduction to Web Sockets The WebSocket API is an advanced technology that makes it possible to open a two-way interactive communication session between the user's browser and a server. With this API, you can send messages to a server and receive event-driven responses without having to poll the server for a reply. Networking
DHCP Basics Dynamic Host Configuration Protocol (DHCP) is a standard protocol that allows a server to dynamically distribute IP addressing and configuration information to clients. In the Classless Inter Domain Routing (CIDR) environment of IPv4 the following parameters should be defined on every IPv4 host:: 1. ip addres, 2. subnet mask, 3. default gateway Networking
Understanding DHCP Relay Agents DHCP relay agent is a small program that relays DHCP/BOOTP messages between clients and servers on different subnets. DHCP/BOOTP relay agents are part of the DHCP and BOOTP standards and function according to the Request for Comments (RFCs), standard documents that describe protocol design and related behavior. Networking
