Ubuntu by default hashes hostnames the known_hosts file (this is not the default openssh behaviour), to make it difficult for anyone reading the file to know what systems you access. If you really wanted to clean out the file, simplest option is probably just delete it and check the keys for servers you know as they arise, but really I'd just
Ubuntu hosts.allow file is the primary configuration file for TCP Wrapper. We can use hosts.allow file to filter access to our system and to secured a service. Setting up hosts.allow and hosts.deny files like protecting your system with a simple firewall. The complete manual for hosts.allow (and hosts.deny)file can be found in hosts_access Change Hostname and Fully Qualified Domain Name (FQDN) on The FQDN is modified in the /etc/hosts file. Open the file in any editor with root privileges: sudo nano /etc/hosts. The file should look something like this: Now the following lines will be set: 123.123.123.123 web1.gridscale.io web1. When finished, it should look like this: Be sure to save the changes before the FQDN is verified with this Unified hosts file with base extensions - GitHub A hosts file, named hosts (with no file extension), is a plain-text file used by all operating systems to map hostnames to IP addresses. Debian/Ubuntu sudo service network-manager restart. Linux Mint sudo /etc/init.d/dns-clean start. Linux with systemd: sudo systemctl restart network.service.
Unified hosts file with base extensions - GitHub
/etc/hosts being recreated each time I restart. · Issue May 19, 2016
How to Setup Local DNS Using /etc/hosts File in Linux
How to Edit the Hosts File in Windows 10 Dec 15, 2019 How to Edit the HOSTS File in Windows - Lifewire