Setup Ethernet Connection on CentOS

Provides a tutorial example on how to review and troubleshoot Ethernet connection on CentOS 8 systems.

If you are running a CentOS system on a desktop computer, it is most likely having an Ethernet connection to the local network. Here is what I did to review and setup the Ethernet connection on my CentOS 8 computer.

1. Make sure the computer is connected with an Ethernet cable to the local network. You should see two lights next to the Ethernet port. If one of them is blinking, then there are some data activities between your computer and the network.

2. Review Ethernet connection settings from the desktop screen.

3. Read the Wired connection details. By default, your IP address, default route (gateway), DNS are dynamically configured by the DHCP (Dynamic Host Configuration Protocol) service from the local network. There is no need to change them.

Link Speed: 100 Mb/s
IPv4 Address: 192.168.1.100
Hardware Address: ...
Default Route: 192.168.1.1
DNS: 192.168.1.1
Ethernet Network Setup on CentOS
Ethernet Network Setup on CentOS

4. You can also verify the Ethernet connection with the "ifconfig" command:

herong$ ifconfig
eno1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
    inet 192.168.1.100  netmask 255.255.255.0  broadcast 192.168.1.255
    inet6 fe80::...:fe80  prefixlen 64  scopeid 0x20<link>
    ether 39:39:...  txqueuelen 1000  (Ethernet)
    RX packets 1162982  bytes 311120747 (296.7 MiB)
    RX errors 0  dropped 61365  overruns 0  frame 0
    TX packets 247671  bytes 58741459 (56.0 MiB)
    TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
    device interrupt 20  memory 0xf7c00000-f7c20000

5. Verify the Internet connection using the "ping" command:

herong$ ping bing.com
PING bing.com (204.79.197.200) 56(84) bytes of data.
64 bytes from a-0001.a-msedge.net (204.79.197.200): icmp_seq=1 ttl=118 time=21.1 ms
64 bytes from a-0001.a-msedge.net (204.79.197.200): icmp_seq=2 ttl=118 time=20.9 ms
...
64 bytes from a-0001.a-msedge.net (204.79.197.200): icmp_seq=9 ttl=118 time=20.8 ms
^C
--- bing.com ping statistics ---
9 packets transmitted, 9 received, 0% packet loss, time 18ms
rtt min/avg/max/mdev = 20.658/21.993/30.929/3.163 ms

6. Check the following if the "ping" command fails:

7. If you have trouble connecting to the Internet during CentOS installation, you can download the *-dvd1.iso version to install CentOS from the ISO image without Internet connection.

Table of Contents

 About This Book

 Introduction to Linux Systems

 Cockpit - Web Portal for Administrator

 Process Management

 Files and Directories

 Users and Groups

 File Systems

 Installing CentOS

 SELinux - Security-Enhanced Linux

Network Connection on CentOS

Setup Ethernet Connection on CentOS

 Network Firewall Tools on CentOS

 "firewalld" and "firewall-cmd" on CentOS

 "nftables" and "nft" on CentOS

 "iptables" Command on CentOS

 "nmap" - Network Mapper on CentOS

 Monitor Network Services on CentOS

 Software Package Manager on CentOS - DNF and YUM

 Running Apache Web Server (httpd) on Linux Systems

 Running PHP Scripts on Linux Systems

 Running MySQL Database Server on Linux Systems

 Running Python Scripts on Linux Systems

 vsftpd - Very Secure FTP Daemon

 Postfix - Mail Transport Agent (MTA)

 Dovecot - IMAP and POP3 Server

 Email Client Tools - Mail User Agents (MUA)

 GCC - C/C++ Compiler

 Conda - Environment and Package Manager

 Tools and Utilities

 References

 Full Version in PDF/EPUB