If you want to free space on Backups you can use find to select a special month: find -newerct "1 Sep 2023" ! -newerct "1 DEC 2023" -delete This command removes files created from 01.Sep.2023 to 01.Dec.2023. ..very useful..
Category: raspian
Major Tools for your IT Systems
A must “USE” in these insecure days: nmap Portscan Tool use nmap -PN IP-Address to check failed Firewall Settings! arp-scan Network Scan to find active devices iftop to detect traffic and used Ports on a physical network Interface! ps aux show active processes on a Linux System htop more human friendly Process Monitor iotop human friendly traffic monitor from CPU/RAM to Drives Daily check Error Logs! Use always Firewalls and Disk/File Encryption! Don’t trust Hardware Protection (TPM) Chips most do communicate by clean signals on copper which can be read out by hardware hacking or magnetic fields! NEVER leave Hardware […]
Script DNS Blocker DNSMASQ
If you tested pihole, you perhaps look for a smaller Command Line version? Install dnsmasq by: sudo apt-get install dnsmasq Here DNS Rule Injector Script (copy & paste): blocker.sh # www.linuxonlinehelp.com 2019 # DNS Blocker for Small Linux with dnsmasq # #!/bin/bash # goto tmp (tmpfs) cd /tmp/ # get URL-Blocklists wget -O blocklist.txt https://v.firebog.net/hosts/Kowabit.txt # get Templates #SET Variables txt='blocklist.txt' IP='0.0.0.0' # set to 0.0.0.0 or to a Webserver with "white Page" showing Text "URL-blocked!! #merge URLs and redirect to wanted IP – Rule creation n=1; while read line; do echo 'address=/'$line'/$IP '>> 02-blocked1.conf ; n=$((n+1)); done < $txt […]
Split Files on embedded Linux Systems
If you run a embedded Linux PC like raspi often some Linux Commands fail without error messages, cause the hardware performance is low tech. Same i have seen on the split command.. to split a 50GB Photos-Archive File to 4Gb on a USB Drive i found out that: sudo split -b 4096m -d -u Photos.tgz Photos-Archive_ fix the job.. Cause option -u disable IO-Caching over the 2.0 USB Port to the RAM of the raspi that the Data of the Output Stream is written direct to the Drive.
Smartmontools unlisted Devices
If you use a Toshiba Canvio 3tb Drive at a raspi then smartmontools will not see the usb drive. Try: sudo smartctl -t long -d sat -s on /dev/sdb -t test long or short -d drive protocol sata = sat -s enforce smart which is off by the usb drive firmware wait XXX Minutes then: sudo smartctl -H -d sat -s on /dev/sdb get status..
Postfix: Automatic UFW Firewall Updates
If you use a Mail Server with Postfix you got daily Spam Attacks by Scripts: How to fix? Install ufw Firewall Run a Scanner Script as cronjob On Debian/Ubuntu: Install ufw: sudo apt-get update && sudo apt-get install ufw && sudo ufw enable && sudo ufw logging off Scan Script: sudo nano /home/user/firewall-update.sh: #!/bin/bash # scan rejected cat /var/log/mail.log | grep rejected | cut -d"[" -f3 | cut -d"]" -f1|grep -v '^$' > /tmp/firewall.txt # insert to Firewall while read line; do sudo ufw insert 1 deny from $line to any; done < /tmp/firewall.txt # scan "denied" cat /var/log/mail.log | […]