Category: Security

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Linux Security

SOLVED: Error apt update – NO_PUBKEY 78BD65473CB3BD13

Error apt update - NO_PUBKEY 78BD65473CB3BD13 Linux

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 Hit:2 http://ppa.launchpad.net/ondrej/php/ubuntu focal InRelease Get:3 http://security.ubuntu.com/ubuntu focal-security InRelease [114 kB] Get:4 http://de.archive.ubuntu.com/ubuntu focal-updates InRelease [114 kB] Ign:5 http://dl.google.com/linux/mod-pagespeed/deb stable InRelease Get:6 http://dl.google.com/linux/mod-pagespeed/deb stable Release [2154 B] Get:7 http://dl.google.com/linux/mod-pagespeed/deb stable Release.gpg […]

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Linux Security Useful

SOLOVED: signatures were invalid EXPKEYSIG 97BD1A0133449C3D Gerardo Orellana

EXPKEYSIG 97BD1A0133449C3D Gerardo Orellana ERROR

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 kB] Ign:2 http://dl.google.com/linux/mod-pagespeed/deb stable InRelease Hit:3 http://ppa.launchpad.net/ondrej/php/ubuntu focal InRelease Get:4 http://dl.google.com/linux/mod-pagespeed/deb stable Release [2154 B] Hit:5 http://de.archive.ubuntu.com/ubuntu focal InRelease Get:6 http://dl.google.com/linux/mod-pagespeed/deb stable Release.gpg [819 B] Get:7 http://de.archive.ubuntu.com/ubuntu focal-updates InRelease [114 […]

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Privacy Security

Free and Public DNS Servers for Family – Block Malicious Content!

Block Malware

Cloudflare Free DNS Servers Protect your home against malware – Using the following DNS resolvers will block malicious content: IPv4 1.1.1.2 1.0.0.2 IPv6 2606:4700:4700::1112 2606:4700:4700::1002 Protect your home against malware and adult content – Next DNS resolvers for Families will block malware and adult content: IPv4 1.1.1.3 1.0.0.3 IPv6 2606:4700:4700::1113 2606:4700:4700::1003 https://developers.cloudflare.com/1.1.1.1/1.1.1.1-for-families OpenDNS (Cisco-owned) OpenDNS Family […]

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Linux Security Servers

Install OpenVPN, DNSCrypt and Pi-Hole – Ubuntu 20

Step by step: Install OpenVPN + Pi-Hole ad-blocker + DNSCrypt-proxy for DoH and DNSSEC Step 1. Update the system: sudo apt update sudo apt upgrade Step 2. Install OpenVPN: wget https://git.io/vpn -O openvpn-install.sh chmod 755 openvpn-install.sh sudo ./openvpn-install.sh Generated opvn file can be used with an OpenVPN client in PC or cell phone. It can be […]

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Security

List with New and Common Cybersecurity Threats

Hackers Online

A summary list of the most current and dangerous threats to our safety and internet security: The DDOS attack on new entrants to online business The newest to enter the online market in various businesses, especially the domain hosting, vpn and sales market have started to run into serious problems regarding the resistance against DDOS attacks […]

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Security Useful

HTTP Security Headers Which Should be Used by all Webmasters

Internet, Security, SSL

The most important HTTP Security Headers which should be used by all webmasters: Content-Security-Policy is an effective measure to protect your site from XSS attacks. By whitelisting sources of approved content, you can prevent the browser from loading malicious assets. Directives include upgrade-insecure-requests; , default-src, script-src, style-src, img-src, object-src, plugin-types to specify permitted sources for scripts, CSS stylesheets, and images. A basic […]

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Security Useful

Secure Your Browser with Secure DNS – DNSSEC, TLS and Encrypted SNI

Well, this is new to many, and for most it is like an alien technology, but this is the future and it is absolutely necessary for the internet, oh, I could say urgently! So what do you need to do to get a better night’s sleep, knowing that your traffic is not “spied on” by […]

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Linux Security Servers Useful

Delete UFW Firewall Rules on Ubuntu & Debian Server – Linux

Firewall Linux Server, Security

If you want to delete active rules (filters) from UFW – Uncomplicated Firewall – , find out that it is very simple and there are two methods to do this, but first of all you have to make sure that UFW is installed and active (enabled): @ sudo ufw status If the displayed result is […]

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Linux Security Useful

How to Change default SSH Port 22 to Increase Security

ssh-putty-server public-key-security

By default, the SSH service runs on port 22, but to prevent automated robots and malicious users from brute-forcing into your server, you should consider changing the default 22 SSH port with another randomly selected one.. To prevent incorrect server configuration, you should choose a port from the range of dynamic / private ports (i.e., […]

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Linux Security Servers Tools

How to allow an IP or range IPs in Fail2ban on Debian/Ubuntu Linux

Fail2Ban-Jail-conf-SERVER Hestia-Control-Panel

I use Fail2Ban primarly to protect my wordpress-servers against brute force attacks. Fail2ban uses iptables (IP packet filter rules of the Linux kernel firewall) to block attackers, so, if you do not want to be left without access to the server, it would be useful to add a list of IPs from where you access the […]