This is a short Tutorial on how to speak the Internet File Transfer Protocol manually by hand. This will help you to better understand the known issues for setting up a_firewall which is able to pass or block FTP. This document is not intended to be a complete reference to the FTP protocol. Actually it […]
Well, one does not simply tells MySQL how much memory it should use. The maximum memory usage comes from a lot of different settings, mostly buffer sizes but it appears that documentations don’t clearly state how to find or set this value.You’ll have to read their post about memory usage, which I greatly recommend anyway. Hopefully, a good-hearted […]
Approach 1. Through LSOF For example, to figure out which process emit DNS queries you can use below command: sudo lsof -PniUDP:53 -r 1 | grep :53 Approach 2. Via ATOP / NETATOP Seek and install the required kernel module and userspace utility (example for Arch Linux): yaourt -Ssq netatop I prefer to use a […]
Параметр сокета SO_REUSEADDR служит для четырех целей. Параметр SO_REUSEADDR позволяет прослушивающему серверу запуститься и с помощью функции bind связаться со своим заранее известным портом, даже если существуют ранее установленные соединения, использующие этот порт в качестве своего локального порта. Эта ситуация обычно возникает следующим образом: 1) запускается прослушивающий сервер; 2) от клиента приходит запрос на соединение, […]
There is a lack of information available on building highly scalable UDP servers on the Internet. What information exists, often falls short of best practices. UDP servers are the central backbone of many video game servers and streaming services, but very few good examples or discussions exist on how to construct them on Windows and Linux. This article […]
Now that our userspace TCP/IP stack has minimal implementations for Ethernet and IPv4, it is time to look into the dreaded Transmission Control Protocol (TCP). Operating on the fourth OSI networking layer1, transport, TCP is responsible for repairing erroneous connections and faults in packet delivery. Indeed, TCP is the workhorse of the Internet, providing reliable communications […]
This time in our userspace TCP/IP stack we will implement a minimum viable IP layer and test it with ICMP echo requests (also known as pings). We will take a look at the formats of IPv4 and ICMPv4 and describe how to check them for integrity. Some features, such as IP fragmentation, are left as an […]
Writing your own TCP/IP stack may seem like a daunting task. Indeed, TCP has accumulated many specifications over its lifetime of more than thirty years. The core specification, however, is seemingly compact1 — the important parts being TCP header parsing, the state machine, congestion control and retransmission timeout computation. The most common layer 2 and layer […]
This tutorial explains how you can set, change and reset (if you’ve forgotten the password) MySQL or MariaDB root passwords. Time and again I see problems like mysqladmin: connect to server at ‘localhost’ failed error: ‘Access denied for user ‘root’@’localhost’ (using password: YES)’. So I thought it’s time to remind you how to solve MySQL […]
Сборка: git clone https://github.com/z3APA3A/3proxy cd 3proxy echo «#define ANONYMOUS» >> src/proxy.h make -f Makefile.Linux all install cp ./scripts/init.d/3proxy.sh /etc/init.d/3proxy chmod 750 /etc/init.d/3proxy update-rc.d 3proxy defaults mkdir /etc/3proxy cp ./scripts/3proxy.cfg /etc/3proxy/3proxy.cfg useradd —system —shell /sbin/nologin —comment «3proxy daemon» —user-group proxy Пример конфига /etc/3proxy/3proxy.cfg : #!/usr/local/bin/3proxy # Yes, 3proxy.cfg can be executable, in this case you should place # […]