System Information- Ciscco Wired Host Networking

Finally, you can find information about network configuration in the System Information application, customarily located under Utilities in Finder. Two sections contain information on wired network interfaces: Ethernet and Network Locations.

Figure 4-11 shows the information in the System Information Ethernet section.

Figure 4-11 Ethernet Section of System Information The Ethernet section of System Information displays information about the physical connection. This Ethernet port connects through a USB port, has a physical interface (MAC) address, and can support up to a 5 Gb/s data rate and the physical interface (MAC) address.

Note

Why is this Ethernet port listed as a USB port?

Because, like many laptops, this particular Macintosh does not have a physical Ethernet port.

This port is a USB to Ethernet adapter plugged into the laptop.

Figure 4-12 shows the correct section of the Locations tab, located under the Network portion of the System Information app.

Figure 4-12 Network Locations Section of System Information The information displayed here is like that displayed in other places in macOS.

Linux

While the average user does not encounter the Linux operating system very often, Linux is widely used to support web-based enterprise-grade applications. If you work in a data center environment, in software development, or with automation, you will almost certainly encounter and use some variant of the Linux operating system.

Note

Each version (distribution or distro) and each version of each distro of Linux has slightly different commands for displaying and setting the network configuration on a host. This section will use examples from Ubuntu 22.04.

Linux’s most common commands used to display network configuration are ifconfig and ip. Figure 4-13 illustrates ipconfig on Ubuntu Linux.

Figure 4-13 ipconfig Output on Ubuntu Linux The fields of interest are

• inet: The IPv4 address.

• netmask: The subnet mask. Here, it is 255.255.240.0, so the prefix length is /28.

• inet6: The IPv6 address.

• prefixlen: The prefix length.

• scope: Whether this is a link-local or global address. since the IPv6 address begins with fe80, this is a link-local address.

• ether: The physical address.

• RX packets: The number of packets received, dropped, etc.

• TS packets: The number of packets transmitted, dropped, etc.

Figure 4-14 shows the output of the ip addr command.

Figure 4-14 ip addr Command on Ubuntu Linux The output of ip addr shows the physical address, the IPv4 address (inet), and the IPv6 address (inet6). This output also includes some DHCP information: alid_lft forever preferred_lft forever means the DHCP lease lifetime is forever.

Configuring a static interface address requires editing /etc/netplan/01-netcfg.yaml, as Figure 4-15 illustrates, and then restarting the network software.

Figure 4-15 01-netcfg.yaml File in Ubuntu Linux

You can edit the file in any text editor, such as VI or Emacs, replacing the addresses: 203.0.113.4 /24 with the correct address and the default gateway, 203.0.113.1, with the correct default gateway address. The nameservers should also be replaced with their correct values.