Para la administración de la red en linea de comandos, existen varios comandos que se pueden utilizar.  

Comando para cambiar de forma directo  cualquier parametro de red:
ifconfig

ip

Herramientas del sistema para habilitar redes ya configuradas

ifup, ifdown
[[https://www.tecmint.com/configure-network-static-ip-address-in-ubuntu/|netplan]]
====== Modelo OSI y TCP/IP ======

====== MAC y ARP ======

====== Herramientas de diagnóstico ======
//**ping**//

//**nslookup**//

//**traceroute**//

//**mtr**//

//**ss**//

//**netstat**//

//**/etc/services**//

//**nmap**//

//**iptraf-ng**//

//**dig**//

//**iftop**//

//**nethogs**//

//**vnstat**//

//**iotop**//

//**iostat**//

====== Configuración de IPs ======

//**ip**//

//**ifconfig**//

//**route**//

====== Calculadoras IP ======
//**ipcalc/ipcalc-ng**//

//**subnetcalc**//

//**sipcalc**//

====== Nombres de interfaz de red ======

//**/etc/network/interfaces**//

//**/etc/resolv.conf**//
Anterior mente solo se editaba el archivo ///etc/resolv.conf// y se agregaban la entrada como
<code bash>
nameserver 8.8.8.8 
nameserver 88.4.4
domain example.com
</code>

Con systemd se debe ver el estado con
<code bash>
systemd-resolve --status
</code>
Editar el archivos  ///etc/systemd/resolved.conf// y cambiar la linea 
<code bash>
DNS=8.8.8.8 8.8.4.4
</code>
Y reiniciar el servicio
<code bash>
systemctl  restart systemd-resolved
</code>
  * https://wiki.archlinux.org/index.php/Systemd-resolved

//**/etc/hosts**//

//**/etc/nsswitch.conf**//

//**hostname**//

Cambiando el hostname
<code bash>
sudo hostnamectl set-hostname only-host
sudo hostnamectl set-hostname host.your-fqdn-here
echo "127.0.0.1 host.your-fqdn-here" >> /etc/hosts
</code>
Verificando
<code bash>
hostnamectl status
dnsdomainname
hostname -f
cat /etc/hostname
</code>
  * https://www.cyberciti.biz/faq/how-to-set-change-fqdn-on-ubuntu-20-04-linux/

//**ifup**//

//**ifdown**//


//**nmcli**//


//**netplan**//

<code>
cat /etc/netplan/50-cloud-init.yaml
network:
  version: 2
  renderer: networkd
  ethernets:
    enp0s3:
      addresses: [ 10.10.10.2/24, 'fd00::229/64' ]
      gateway4: 10.10.10.1
      gateway6: fd00::1
      nameservers:
          search: [mydomain, otherdomain]
          addresses: [10.10.10.1, 1.1.1.1]
</code>

  * https://netplan.io/
//**NetworkManager**//


====== systemd ======
<code>
systemctl disable NetworkManager
systemctl enable systemd-networkd
systemctl enable systemd-resolved

rm /etc/resolv.conf
ln -s /run/systemd/resolve/resolv.conf /etc/resolv.conf
mkdir /etc/systemd/network

vi /etc/systemd/network/20-dhcp.network
[Match]
Name=enp0s3*

[Network]
#DHCP=yes
Address=10.10.0.10/24
Gateway=10.10.0.1
DNS=8.8.8.8

</code>

====== Referencias ======
  * https://netplan.io/examples
  * https://www.tecmint.com/set-permanent-dns-nameservers-in-ubuntu-debian/
  * https://wiki.archlinux.org/index.php/Network_bridge
  * http://www.microhowto.info/troubleshooting/troubleshooting_ethernet_bridging_on_linux.html
  * https://vincent.bernat.ch/en/blog/2017-linux-bridge-isolation
  * https://hechao.li/2017/12/13/linux-bridge-part1/
  * https://blog.elastocloud.org/2015/07/qemukvm-bridged-network-with-tap.html
  * https://www.linux-kvm.org/page/Networking
  * https://wiki.libvirt.org/page/Net.bridge.bridge-nf-call_and_sysctl.conf
  * https://www.cisco.com/c/en/us/td/docs/routers/xr12000/software/xr12k_r3-9/routing/configuration/guide/xr12krc39_chapter8.html#task_1011694
  * https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/snmp/configuration/xe-16/snmp-xe-16-book/nm-snmp-cfg-snmp-support.html
  * https://www.cisco.com/c/en/us/td/docs/routers/asr9000/software/asr9k-r6-5/system-management/configuration/guide/b-system-management-cg-asr9000-65x/b-system-management-cg-asr9000-65x_chapter_0101.html
  * https://www.cisco.com/c/dam/en/us/td/docs/routers/asr9000/mib/guide/asr9k-mibs.pdf
  * https://www.cacti.net/downloads/docs/html/graph_snmp_oid.html
  * https://shivering-isles.com/Configure-DoT-on-systemd-resolved
  * https://www.golinuxcloud.com/nmcli-command-examples-cheatsheet-centos-rhel/