• https://wiki.debian.org/ru/NetworkConfiguration
• Настройка сети вручную
• Ошибка в логах ядра. request_sock_TCP: Possible SYN flooding

# apt install iproute2

$ ip link show

# ip link set enp0s3 up

# ip addr add 172.16.1.X/24 dev enp0s3

# ip addr show dev enp0s3

# ip route add default via 172.16.1.254

# ip addr del 172.16.1.X/24 dev enp0s3

# ip addr flush dev enp0s3

# dhclient enp0s3

# ip a

ubuntu# apt install net-tools

# ifconfig -a

# ifconfig eth0 inet 172.16.1.X/24

# route add default gw 172.16.1.254

# hostname server.corpX.un

• 18 commands to monitor network bandwidth on Linux server

# ip link show

# ip a

# ifconfig -a

# ethtool eth0
# ethtool -s eth1 speed 100 duplex full
# ethtool -s eth1 autoneg on

# arp -n
# ip n s
# ip n f all

# netstat -rn
# ip r

# ping 8.8.8.8

# tracepath -n ya.ru

# netstat -tupan
# lsof -i -P

# ss -anptu
# ss -lnp | grep ':80'

# количество подключений с каждого адреса (https://serverfault.com/questions/421310/check-the-number-of-active-connections-on-port-80)
# ss -tn src :80 or src :443 | tr -s ' ' | cut -d ' ' -f5  | cut -d ':' -f1 | sort | uniq -c | sort -n

• Переименование интерфейсов

# hostnamectl set-hostname server.corpX.un

# cat /etc/hostname

server.corpX.un

# cat /etc/hosts </code>

127.0.0.1       localhost

172.16.1.X      server.corpX.un server

# apt remove resolvconf

# cat /etc/resolv.conf

nameserver 172.16.1.254
search corpX.un

• Руководство по Ubuntu. Настройка подключения к интернету
• Форум русскоязычного сообщества Ubuntu. Тема: Сетевая конфигурация

# cat /etc/network/interfaces

auto lo
iface lo inet loopback

auto enp0s3
iface enp0s3 inet static
        address 172.16.1.X
        netmask 255.255.255.0
        gateway 172.16.1.254

# apt install resolvconf
#        dns-nameservers 172.16.1.254
#        dns-search corpX.un


### Alias example ###
# auto eth0:0
# iface eth0:0 inet static
#         address 192.168.1.10
#         netmask 255.255.255.0

### Bridge example ###
### http://bwachter.lart.info/linux/bridges.html ###
###
### https://www.mail-archive.com/debian-bugs-dist@lists.debian.org/msg1812219.html
### В Debian 11 требуется Promoskye режим в виртуализации
###
# apt install bridge-utils

# auto br0
# iface br0 inet static
#         address 172.16.1.X
#         netmask 255.255.255.0
#         gateway 172.16.1.254
#         bridge_ports eth0 eth1
#         bridge_stp off
#         bridge_maxwait 5
#         post-up /sbin/brctl setfd br0 0

### 802.1q example ###
# apt install vlan

# auto vlan2
# iface vlan2 inet static
#         address 192.168.100+X.1
#         netmask 255.255.255.0
#         mtu 1500
#         vlan_raw_device eth0

### UP iface without ip example ###
# auto eth1
# iface eth1 inet manual
#         up ip link set eth1 up

# ifup enp0s3

# ifdown --force enp0s3

client1# dhclient eth0

client1# cat /etc/hostname

client1

client1# :> /etc/resolv.conf

или Команда chattr

client1# cat /etc/hosts

127.0.0.1     localhost

127.0.1.1 client1

• Без GUI

# cat /etc/network/interfaces

auto lo
iface lo inet loopback

auto eth0
iface eth0 inet dhcp

• С GUI
• Инсталяция системы в конфигурации Desktop

# apt install network-manager

• Cloud-init: автоматическая установка hostname для виртуальной машины
• Ubuntu Bionic: Netplan
• How to change hostname on Ubuntu 18.04 Bionic Beaver Linux
• How to Assign Static IP Address on Ubuntu 20.04 LTS
• Override Ubuntu 20.04 DNS using systemd-resolved

• Core tutorial with QEMU

# apt purge cloud-init

apt purge ifupdown

• Формат YAML
• Netplan FAQ
• Netplan configuration examples !!! Все варианты !!!

# netplan status --all

# cat /etc/netplan/01-netcfg.yaml

network:
  version: 2
  ethernets:
    enp0s3:
      addresses: [172.16.1.200+X/24]
      gateway4: 172.16.1.254

#      routes:
#        - to: default
#          via: 172.16.1.254

#      nameservers:
#        addresses: [172.16.1.254]

# netplan try

# netplan apply

• How to switch back networking to /etc/network/interfaces on Ubuntu 20.04 Focal Fossa Linux

# apt install ifupdown net-tools

ubuntu20/22# rm /etc/netplan/00-installer-config.yaml

ubuntu24# rm /etc/netplan/50-cloud-init.yaml

• archlinux systemd-resolved (Русский)

# cat /etc/resolv.conf

search corpX.un
nameserver 127.0.0.53

# resolvectl status
  или
# systemd-resolve --status

# cat /etc/systemd/resolved.conf

[Resolve]
DNS=172.16.1.254

# systemctl restart systemd-resolved

• How to disable systemd-resolved in Ubuntu

# systemctl disable systemd-resolved

# systemctl stop systemd-resolved

# rm /etc/resolv.conf    # this is link

• Сетевые настройки в CentOS 7
• How to configure a static IP address on RHEL 8 / CentOS 8 Linux

# cat /etc/hostname

server.corpX.un

# cat /etc/sysconfig/network-scripts/ifcfg-eth0

# HWADDR=00:0C:29:C0:F8:54
DEVICE=eth0
ONBOOT=yes
BOOTPROTO=static
IPADDR=172.16.1.100+X
NETMASK=255.255.255.0
DNS1=172.16.1.254
DOMAIN=corpX.un
GATEWAY=172.16.1.254

# cat /etc/sysconfig/network-scripts/ifcfg-eth0:0

DEVICE=eth0:0
BOOTPROTO=static
ONBOOT=yes
# HWADDR=00:0C:29:C0:F8:54
IPADDR=10.N.M.100+X
NETMASK=255.255.255.0

Для Centos 6

# cat /etc/sysconfig/network

# NETWORKING=yes
# NETWORKING_IPV6=no
# HOSTNAME=centos.corpX.un
# GATEWAY=172.16.1.254

# hostname centos.corpX.un

# ifup enp0s3

• Gentoo Linux x86 Handbook: Настройка сети

# cat /etc/conf.d/hostname

hostname="server.corpX.un"

# cd /etc/init.d
# ln -s net.lo net.enp0s3

# cat /etc/conf.d/net

config_enp0s3="172.16.1.X/24"
routes_enp0s3="default via 172.16.1.254"

# rc-update add net.enp0s3 default

root@nessus.isp.un:~# host ru.archive.ubuntu.com

ru.archive.ubuntu.com is an alias for mirror.yandex.ru.
mirror.yandex.ru has address 213.180.204.183
mirror.yandex.ru has IPv6 address 2a02:6b8:0:201::1

root@nessus.isp.un:~# cat /etc/gai.conf

...
precedence 2a02:6b8::/32   0
...

• Отказоустойчивость доступа к сети в Linux
• Ethernet bonding — это объединение двух или более физических сетевых интерфейсов в один виртуальный для обеспечения отказоустойчивости и повышения пропускной способности

# apt install ifenslave

# cat /etc/network/interfaces

auto lo
iface lo inet loopback

iface eth0 inet manual

iface eth1 inet manual

auto bond0
iface bond0 inet static
        address 192.168.X.10
        netmask 255.255.255.0
        gateway 192.168.X.1
        slaves eth0 eth1
        bond-mode active-backup
        bond-miimon 100
        bond-primary eth0

# cat /etc/netplan/01-netcfg.yaml

network:
  version: 2
  bonds:
    bond0:
      addresses: [192.168.X.10/24]
      gateway4: 192.168.X.1
      interfaces: [eth0, eth1]
      parameters:
        mode: active-backup
        mii-monitor-interval: 100
        primary: eth0
  ethernets:
    eth0: {}
    eth1: {}

# cat /proc/net/bonding/bond0