Author Archives: marslert

Rspamd is an advanced spam filtering system that allows evaluation of messages by a number of rules including regular expressions, statistical analysis and custom services such as URL black lists. Each message is analysed by Rspamd and given a spam score. According to this spam score and the user’s settings, Rspamd recommends an action for […]

A Secure Shell (SSH) tunnel consists of an encrypted tunnel created through an SSH protocol connection. Users may set up SSH tunnels to transfer unencrypted traffic over a network through an encrypted channel. Testing environment Host A : Can’t connect cPanel port 2086 of Host B. Behind firewall connection that restricts outgoing port 2086. Host […]

1. speedtest-cli or https://www.speedtest.net/ wget https://raw.githubusercontent.com/sivel/speedtest-cli/master/speedtest.py ; chmod +x speedtest.py ./speedtest.py   2. iperf3 Download at https://iperf.fr/iperf-download.php. Can test the network connectivity speed in between 2 host or source/destination. Server command iperf3 -s Client command iperf3 -c x.x.x.x -V -t 10 Replace x.x.x.x with server IP Based on above test, the connection bandwidth speed in between these 2 […]

I would like to share that the host CPU usage in task manager does not show the CPU usage from guest machine level. You may refer https://blogs.msdn.microsoft.com/virtual_pc_guy/2008/02/28/hyper-v-virtual-machine-cpu-usage-and-task-manager/ for a better explanation.To get the performance bottleneck, performonce monitor function is needed. A counter name Hyper-V Hypervisor Logical Processor(_Total)\% Total Runtime must be referred. According to https://docs.microsoft.com/en-us/windows-server/administration/performance-tuning/role/hyper-v-server/detecting-virtualized-environment-bottlenecks, if the Hyper-V Hypervisor Logical Processor(_Total)\% Total […]

We are going to looking on optimizing WordPress site through caching plugin to improve TTFB. What is TTFB? Time to first byte (TTFB) is a metric for determining the responsiveness of a web server. It measures the amount of time between creating a connection to the server and downloading the contents of a web page. […]