[Linux]CentOS 설치 후 초기 세팅 및 명령어 알아보기

네트워크 설정 

1. 인터넷 연결 확인 

• 인터넷 연결이 안되어 있을 시 화면

[root@localhost ~]# ping 8.8.8.8
connect: Network is unreachable

• ifup 명령어를 사용하여 네트워크 시작

[root@localhost ~]# ifup enp0s3
Connection successfully activated (D-Bus active path: /org/freedesktop/NetworkManager/ActiveConnection/2)

•  다시 인터넷 연결 확인 

[root@localhost ~]# ping 8.8.8.8
PING 8.8.8.8 (8.8.8.8) 56(84) bytes of data.
64 bytes from 8.8.8.8: icmp_seq=1 ttl=54 time=35.8 ms
64 bytes from 8.8.8.8: icmp_seq=2 ttl=54 time=33.5 ms
64 bytes from 8.8.8.8: icmp_seq=3 ttl=54 time=33.7 ms
64 bytes from 8.8.8.8: icmp_seq=4 ttl=54 time=35.1 ms
64 bytes from 8.8.8.8: icmp_seq=5 ttl=54 time=33.5 ms
64 bytes from 8.8.8.8: icmp_seq=6 ttl=54 time=33.8 ms
64 bytes from 8.8.8.8: icmp_seq=7 ttl=54 time=34.5 ms
^C
--- 8.8.8.8 ping statistics ---
7 packets transmitted, 7 received, 0% packet loss, time 6014ms
rtt min/avg/max/mdev = 33.540/34.308/35.806/0.821 ms

2. 고정 IP 설정 

•  /etc/sysconfig/network-scripts/  디렉토리 이동 
• 고정 IP 설정을 원하는 네트워크 ifcfg-device명 파일 수정

vi ifcfg-enp0s3

TYPE=Ethernet
PROXY_METHOD=none
BROWSER_ONLY=no
#BOOTPROTO=dhcp
DEFROUTE=yes
IPV4_FAILURE_FATAL=no
IPV6INIT=yes
IPV6_AUTOCONF=yes
IPV6_DEFROUTE=yes
IPV6_FAILURE_FATAL=no
IPV6_ADDR_GEN_MODE=stable-privacy
NAME=enp0s8
UUID=ec86f2be-e7d4-4b3b-8d73-ceacc9e95533
DEVICE=enp0s8
ONBOOT=yes

BOOTPROTO="none"
IPADDR="192.168.0.10"
NETMASK="255.255.255.0"
GATEWAY="192.168.0.1"
DNS1="8.8.8.8"
DNS2="8.8.4.3"

• 네트워크 재시작 

      1. CentOS 8 이전

service network restart

     2.  CentOS 8

nmcli networking off
nmcli networking on

yum 업데이트 및 필요 유틸 설치

yum -y update
yum install -y net-tools 
yum install -y tree 
yum install -y gcc

sudoers 설정 

visudo 

agens   ALL=(ALL:ALL) ALL
agens   ALL=(ALL)     NOPASSWD: ALL

방화벽 설정

• 현재 오픈된 포트 확인 

[agens@localhost log]$ netstat -tulpn | grep LISTEN
(Not all processes could be identified, non-owned process info
 will not be shown, you would have to be root to see it all.)
tcp        0      0 0.0.0.0:22              0.0.0.0:*               LISTEN      -
tcp        0      0 127.0.0.1:5432          0.0.0.0:*               LISTEN      24970/postgres
tcp        0      0 127.0.0.1:25            0.0.0.0:*               LISTEN      -
tcp6       0      0 :::22                   :::*                    LISTEN      -
tcp6       0      0 ::1:5432                :::*                    LISTEN      24970/postgres
tcp6       0      0 ::1:25                  :::*                    LISTEN      -

• 방화벽 iptables 확인 

iptables -L --line

• 방화벽 포트오픈 추가

firewall-cmd --permanent --zone=public --remove-port=3306/tcp

• 방화벽 포트오픈 제거

firewall-cmd --permanent --zone=public --remove-port=3306/tcp

• 방화벽 재시작 

sudo firewall-cmd --reload

• 방화벽 해제 

systemctl stop firewalld

 

shell에서 절대 경로 표시 ( bash_profile에 추가)

export PS1=[`whoami`:'$PWD']#

NIC UUID 확인

[root@localhost ~]# nmcli connection
NAME                UUID                                  TYPE      DEVICE
enp0s3              09995200-8842-471f-99d7-0b4da7074c98  ethernet  enp0s3
Wired connection 1  0d5a6ef6-d88e-34c6-ad6d-1fc5f7e8e047  ethernet  enp0s9
enp0s8              774950fb-50f6-400e-a7de-f489a487d739  ethernet  --