![How to check open ports in Linux Ipfail](https://ipfail.org/wp-content/uploads/2022/11/How-to-check-open-ports-in-Linux-Ipfail.png)
How to check open ports in Linux: netstat, ss, nmap, iptables, cat
Different Linux commands to check open ports in Linux: Using netstat to list open ports sudo netstat -tulpn | grep LISTEN tcp 0 0 127.0.0.53:53
![Error apt update - NO_PUBKEY 78BD65473CB3BD13 Linux](https://ipfail.org/wp-content/uploads/2022/07/Error-apt-update-NO_PUBKEY-78BD65473CB3BD13-Linux.png)
SOLVED: Error apt update – NO_PUBKEY 78BD65473CB3BD13
If after the linux apt update command you receive an error about NO_PUBKEY, similar to what is seen below: root@epyc:~# apt update Hit:1 http://de.archive.ubuntu.com/ubuntu focal InRelease
![EXPKEYSIG 97BD1A0133449C3D Gerardo Orellana ERROR](https://ipfail.org/wp-content/uploads/2022/07/EXPKEYSIG-97BD1A0133449C3D-Gerardo-Orellana-ERROR.png)
SOLOVED: signatures were invalid EXPKEYSIG 97BD1A0133449C3D Gerardo Orellana
If after the linux apt update command you receive an error similar to what is seen below: root@epyc:~# apt update Get:1 http://security.ubuntu.com/ubuntu focal-security InRelease [114
![IO linux Error](https://ipfail.org/wp-content/uploads/2022/02/Error_1645917342.jpg)
Fixing kernel error AMD-Vi IO_PAGE_FAULT – Linux
Without any clear reason, today an error appeared on my home server, in fact the server crashed and did not respond to any commands, the
![Linux OS Server](https://ipfail.org/wp-content/uploads/2022/02/linux_1645916117.png)
Hot to find your Linux Kernel Version
Below are the usual 4 Commands to Find Linux Kernel Version uname uname -r # find Linux kernel version uname -a # for all information related to
![Kernel, Linux O(S](https://ipfail.org/wp-content/uploads/2022/02/kernel_linux_1645915525.jpg)
How to Update Linux Kernel to 5.5.0
To upgrade to linux 5.5.0 kernel, you can perform the following steps: 1st) Download the following files to an empty folder (for 64bit & generic
![Linux Sleep](https://ipfail.org/wp-content/uploads/2022/02/linux_1645915002.png)
Stop Random Standy/Sleep in Ubuntu-Linux Server
My Ubuntu Server 18.04, is without a monitor / keyboard connected (headless server) and has been running for several years, but today I updated to
![Server Disk Drive Tools Linux Format](https://ipfail.org/wp-content/uploads/2020/12/server_1608767648.jpg)
Automatic REBOOT if needed after apt-get upgrade – Linux
Sometimes after the execution of the apt-get upgrade command is finished, a restart is required, but this is not displayed after the command is completed,
![rename Files on linux](https://ipfail.org/wp-content/uploads/2021/11/files_1638124914.png)
Change the extension of multiple files in Linux
1). Using Linux find command Using find command to rename all .oldext files under directory structure with a new extension: .newext find . -type f