Ace Your 102-500 LPIC Level 1 Exam

The connection types, as seen in nmcli connection show, are the types of network configurations that Network Manager can manage. They are not the same as the network protocols or layers, such as TCP or IPv6, but rather the logical or physical ways of connecting to a network. According to the Network Manager reference manual1, some of the possible connection types are:

wifi: This connection type is for wireless network interfaces that use the IEEE 802.11 standard. It requires a wifi device and a wifi access point to establish a connection. The connection settings include the SSID, security, password, etc.

bridge: This connection type is for creating a network bridge, which is a device that connects two or more network segments and forwards packets between them. It requires a bridge device and one or more slave devices to be attached to the bridge. The connection settings include the bridge name, MAC address, STP, etc.

vpn: This connection type is for creating a virtual private network, which is a secure tunnel between two or more network endpoints. It requires a VPN plugin and a VPN service provider to establish a connection. The connection settings include the VPN type, service name, user name, password, etc.

The other options are not correct because:

tcp: This is not a connection type, but a network protocol that operates at the transport layer. It provides reliable, ordered, and error-checked delivery of data between applications. It is not a configuration option for Network Manager.

Ethernet: This is not a connection type, but a network technology that operates at the physical and data link layers. It defines the standards for wiring, signaling, and framing of data packets. It is not a configuration option for Network Manager, but rather a device type that can be used by other connection types, such as bridge or vpn.

ipv6: This is not a connection type, but a network protocol that operates at the network layer. It provides addressing and routing of data packets across networks. It is not a configuration option for Network Manager, but rather an IP configuration option that can be used by other connection types, such as wifi or vpn. References:

 systemd-journald is a system service that collects and stores logging data from various sources, such as kernel, user-mode programs, and services1. It creates and maintains structured, indexed journals that include metadata and binary data where necessary1. The journal format is secure and unfakeable1. systemd-journald is not incompatible with syslog and can coexist with it. It can forward log messages to a syslog daemon for further processing, filtering, or storage2. This can be enabled by setting the ForwardToSyslog option to yes in the /etc/systemd/journald.conf file2. systemd-journald does not only process messages of systemd, but also messages of any other tools that use the standard logging interfaces, such as syslog(3), sd_journal_print(3), or systemd-cat(1)1. systemd-journald also supports syslog facilities, such as kern, user, and auth, which are used to specify the type of program that is logging the message3. These facilities can be used to filter the journal entries by using the -p or --priority option of the journalctl command4. For example, to show only kernel messages, we can use journalctl -p kern4. References:

systemd-journald.service

Introduction to the Systemd journal

systemd/Journal

journalctl: Query the systemd Journal

The command journalctl is included in systemd and supports selecting messages from the systemd journal by criteria such as time or unit name. The systemd journal is a binary log file that stores system and service messages. The journalctl command can be used to view, filter, export, and manipulate the journal entries. For example, to show all messages from a specific unit, such as sshd.service, the command would be:

journalctl -u sshd.service

To show all messages from a specific time range, such as yesterday, the command would be:

journalctl --since=yesterday

The journalctl command has many options and arguments that can be used to customize the output and perform various operations on the journal. For more information, see the man page of journalctl or the official documentation1. References: [LPI 102-500 Exam Objectives], Topic 106.2: System logging, Weight: 3. [systemd-journald.service(8) — systemd — Debian unstable — Debian Manpages], Section NAME.