Engineering and technology notes

tcp – iptables/haproxy limit packets per second

Jovan Stosic April 29, 2022

iptables -A INPUT -p tcp --dport 1234 -m state --state NEW -j ACCEPT

iptables -I INPUT -p tcp --dport 1234 -m hashlimit --hashlimit-mode srcip,srcport --hashlimit-name HASHNAME --hashlimit-htable-max 5000 --hashlimit-htable-expire 10000 --hashlimit-above 5/sec -j DROP

Source: tcp – iptables/haproxy limit packets per second – Server Fault

tcp – iptables/haproxy limit packets per second was last modified: April 29th, 2022 by Jovan Stosic

Help needed – Cron job not working with HA OS – Configuration

Jovan Stosic April 25, 2022

Instead of Cron jobs you could schedule it directly into HA using automation and shell commands. I have tons of these that I use for various purposes and doing it in HA has the added benefit of being able to set conditions on which scripts to execute and when. For example, here is what I use to truncate my log every hour:

shell_commands.yaml:

shell_rotate_log: '/config/logreset.sh'

automation:

alias: 'Schedule: Clear Logs Each Hour'
description: ''
trigger:
  - platform: time_pattern
    hours: /1
    minutes: '59'
condition: []
action:
  - service: shell_command.shell_rotate_log
    data: {}
mode: single

Source: Help needed – Cron job not working with HA OS – Configuration – Home Assistant Community

Help needed – Cron job not working with HA OS – Configuration was last modified: April 25th, 2022 by Jovan Stosic

arduino-examples/SerialEvent.ino at main · arduino/arduino-examples · GitHub

Jovan Stosic April 21, 2022

/*
Serial Event example
When new serial data arrives, this sketch adds it to a String.
When a newline is received, the loop prints the string and clears it.
A good test for this is to try it with a GPS receiver that sends out
NMEA 0183 sentences.
NOTE: The serialEvent() feature is not available on the Leonardo, Micro, or
other ATmega32U4 based boards.
created 9 May 2011
by Tom Igoe
This example code is in the public domain.
https://www.arduino.cc/en/Tutorial/BuiltInExamples/SerialEvent
*/
String inputString = ““; // a String to hold incoming data
bool stringComplete = false; // whether the string is complete
void setup() {
// initialize serial:
Serial.begin(9600);
// reserve 200 bytes for the inputString:
inputString.reserve(200);
}
void loop() {
// print the string when a newline arrives:
if (stringComplete) {
Serial.println(inputString);
// clear the string:
inputString = ““;
stringComplete = false;
}
}
/*
SerialEvent occurs whenever a new data comes in the hardware serial RX. This
routine is run between each time loop() runs, so using delay inside loop can
delay response. Multiple bytes of data may be available.
*/
void serialEvent() {
while (Serial.available()) {
// get the new byte:
char inChar = (char)Serial.read();
// add it to the inputString:
inputString += inChar;
// if the incoming character is a newline, set a flag so the main loop can
// do something about it:
if (inChar == ‘\n‘) {
stringComplete = true;
}
}
}

  • © 2022 G

Source: arduino-examples/SerialEvent.ino at main · arduino/arduino-examples · GitHub

arduino-examples/SerialEvent.ino at main · arduino/arduino-examples · GitHub was last modified: April 21st, 2022 by Jovan Stosic