Managing Custom iptables Rules for Docker Container Services
Scenario
A Docker container exposes a service on a specific port. The goal is to restrict access to this port so that only specific remote hosts are permitted, while all others are denied.
Background: Traffic Flow in Docker
When Docker runs, it modifies the host's iptables rules. External traffic destined for a container does not pass through t ...
Posted on Wed, 05 Aug 2026 16:42:01 +0000 by The_Assistant
Managing Linux Network Interfaces with NetworkManager
Modern Linux distributions have shifted from the legacy network service to NetworkManager, particularly since RHEL 7. This change addresses the increasing complexity of network parameters and provides a unified configuration layer. Instead of manually editing files and restarting services to load configurations into kernel memory, NetworkManage ...
Posted on Mon, 27 Jul 2026 16:59:07 +0000 by shadow1200
Configuring Network Settings in Linux
IP Address ClassificationIPv4 addresses are categorized into five classes (A through E), although D (multicast) and E (experimental) are rarely configured on standard hosts.Class A: The first octet represents the network (1-127). The loopback address consumes 127.0.0.0/8, leaving 126 valid networks. Each network supports 2^24 - 2 hosts. Default ...
Posted on Sun, 26 Jul 2026 16:16:19 +0000 by George Botley
Port Mapping and Container Linking in Docker
Port Mapping
When running containers that need to be accessed from outside the host machine—such as a private Docker registry—it's common to use the -p flag. For example:
docker run -d -p 5000:5000 -v /opt/data/registry:/tmp/registry registry
This maps port 5000 on the host to port 5000 inside the container. Without such a mapping, external sy ...
Posted on Sat, 25 Jul 2026 16:09:36 +0000 by luanne
Essential Linux Commands for System Administration
The Linux terminal serves as the interface between users and the kernel, interpreting shell commands that control system operations. Mastering these commands is essential for effective system management.
Keyboard Shortcuts
Ctrl+Alt+T: Launch new terminal
Ctrl+Shift+N: Open terminal in current directory
Privilege Escalation
The sudo comand all ...
Posted on Wed, 15 Jul 2026 17:25:45 +0000 by android6011
Building Networked Applications with Java Sockets and Netty
Computer Network Fundamentals
A computer network is a system that interconnects autonomous computing devices through transmission media, communication facilities, and standardized protocols to enable resource sharing and data exchange. Network programming involves writing software that allows two or more networked devices to transfer data betwe ...
Posted on Wed, 15 Jul 2026 17:23:52 +0000 by sargenle
Analyzing OSPF Adjacency Establishment via Packet Capture
Network Topology
Device Configuration
[Router-A] ospf 1 router-id 10.0.0.1
[Router-A-ospf-1] area 0
[Router-A-ospf-1-area-0.0.0.0] network 10.0.0.1 0.0.0.0
[Router-A-ospf-1-area-0.0.0.0] network 192.168.10.1 0.0.0.0
[Router-A] interface LoopBack 0
[Router-A-LoopBack0] ip address 10.0.0.1 255.255.255.255
[Router-A-LoopBack0] interface GigabitEth ...
Posted on Tue, 14 Jul 2026 16:42:40 +0000 by coelex
Python Socket Programming Essentials
Python facilitates network communication through two abstraction tiers.
The first tier utilizes fundamental Socket APIs derived from BSD standards, granting direct access to operating system interface methods. The second tier employs higher-level modules containing server-centric classes designed to streamline the development of network service ...
Posted on Mon, 13 Jul 2026 16:42:53 +0000 by alcoholic1
Managing HTTP Requests with OKHttpUtil
OKHttpUtil Features
Automatically determines whether a URL is HTTP or HTTPS without requiring additional code.
Cookies are recorded by default, enabling features like simulated login where subsequent requests remain authenticated after the initial login.
Automatically handles 304 redirects and subsequent requests.
Supports proxy configuration. ...
Posted on Mon, 13 Jul 2026 16:34:24 +0000 by socratesone
Configuring Docker Container Networks
Configuring Docker Container Networks
In Docker, network configuration is crucial as it determines how containers communicate with each other and access external networks. This article will cover how to configure Docker container networks, including network types, network modes, and network drivers.
Network Types
Docker offers several network t ...
Posted on Mon, 13 Jul 2026 16:03:24 +0000 by FireyIce01