General command line options. There is a man page available, as there are for most command line tools, though the use of this tool is simple enough to describe here briefly. Simply decide what RHN scheduled actions should be enabled for use by system administrators. The following options enable the various scheduled action modes:. Once a mode is set — and for many, rhn-actions-control --enable-all is common — your system is now ready for config management through RHN. If you are not running the X Window System or prefer the command line version, skip to Section 2.
If started by a user other than root, the Red Hat Update Agent prompts you for the root password. The Red Hat Update Agent Configuration Tool can be started by typing the command up2date --config at a shell prompt for example, an xterm or a gnome-terminal. General Settings. For example, to use the proxy server squid. Additionally, if your proxy server requires a username and password, select the Use Authentication option and enter your username and password in the respective text fields.
Some of these tasks can be challenging. However, when dealing with connectivity issues, using the right tools will assist you in achieving the results in a faster and consistent way.
The ip command is an all-around utility to show and manipulate network objects on your Linux system, including IP addresses, routes, and ARP tables. It's a useful tool to configure the network, as well as to troubleshoot network connectivity issues. The ip command replaces the functionality of many commands provided with the old net-tools package such as ifconfig , route , and arp , but it adds many other features. In its most basic form, you can just run ip and provide a network object to manipulate, such as an address, link, or route, and a subcommand to perform an action.
If you do not give a subcommand, many objects default to the show subcommand to display information related to that object. Because show is the default subcommand, you can also obtain the same result by running ip link or even ip l many objects recognize an abbreviation. Show network statistics -s in human readable format -h for a specific network interface:. The ip command is a lower-level interface to configure network options on your Linux system.
While it's useful as a troubleshooting tool, it may be harder to set the network with it. For this reason, many distributions provide a higher-level interface to accomplish the same task. Next, let's take a look at the Network Manager configuration tool nmcli , which provides an integrated way to configure the network. Network Manager runs as a daemon, and its goal is to provide a higher-level interface to make network configuration easier and more automated.
It's common for users of desktop Linux or servers with a graphical interface to use Network Manager GUI clients to configure the network. For cases where you work with headless servers or if you want to automate configuration via shell scripts, the nmcli tool comes in handy. Network Manager and nmcli are a versatile combination that allow you to verify and configure many network options. The basic syntax for nmcli is:. It's impossible to cover all the options on a single blog post.
Let's check some examples of how to use nmcli for common network configurations tasks. For more examples, consult the official nmcli-examples page or the man pages with man nmcli-examples. This interface provides help and auto-completion via the Tab key, which guides you through the many options available. In the editor, you can define specific parameters with the set command.
Use the Tab key auto-completion to see all available options:. When you finish your changes, save them to the connection and quit to complete the operation:. Network Manager and nmcli are a complete solution for network configuration. If you have never used it before, start with some of the basic commands and gradually move to more complex settings.
Consult the man pages and examples to execute specific tasks. Next, let's review some commands that help you with network troubleshooting, starting with name resolution. When managing connectivity issues, DNS name resolution is often a source of headaches. The nslookup utility helps you check and troubleshoot DNS name resolution.
Install it with dnf :. To quickly check the name resolution for a particular host, use nslookup with the hostname as an argument. The command uses the default DNS configuration for the name resolution:.
If the name resolution fails, you can use an alternative name server for the resolution by providing its address as the third argument:. This information is useful for troubleshooting as it helps to identify whether the issue is local due to a specific server, or something more extensive. The nslookup utility is a useful tool to help troubleshoot network issues related to DNS name resolution.
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