https://dikapediav2.com/wiki/index.php?action=history&feed=atom&title=Ethtool 2026-05-15T09:12:20Z Revision history for this page on the wiki MediaWiki 1.41.0 https://dikapediav2.com/wiki/index.php?title=Ethtool&diff=72&oldid=prev 2024-08-27T00:13:28Z

<p>Created page with &quot;&lt;b&gt;ethtool&lt;/b&gt; - query or control network driver and hardware settings. Use this command to verify that your link is up (the Ethernet is physically connected to the network). https://www.poftut.com/linux-ethtool-tutorial-usage-examples/ ====Is it plugged in?==== ---- On a physical server, with physical cables connected to them, it would probably look like: $ sudo ethtool eth0 Settings for eth0: Supported ports: [ TP ] Supported link modes: 10baseT/Half 10bas...&quot;</p> <p><b>New page</b></p><div>&lt;b&gt;ethtool&lt;/b&gt; - query or control network driver and hardware settings. Use this command to verify that your link is up (the Ethernet is physically connected to the network). <br /> <br /> <br /> https://www.poftut.com/linux-ethtool-tutorial-usage-examples/<br /> <br /> <br /> ====Is it plugged in?====<br /> ----<br /> <br /> <br /> On a physical server, with physical cables connected to them, it would probably look like:<br /> $ sudo ethtool eth0<br /> Settings for eth0:<br /> Supported ports: [ TP ]<br /> Supported link modes: 10baseT/Half 10baseT/Full<br /> 100baseT/Half 100baseT/Full<br /> 1000baseT/Half 1000baseT/Full<br /> Supports auto-negotiation: Yes<br /> Advertised link modes: 10baseT/Half 10baseT/Full<br /> 100baseT/Half 100baseT/Full<br /> 1000baseT/Half 1000baseT/Full<br /> Advertised auto-negotiation: Yes<br /> Speed: 100Mb/s<br /> Duplex: Full<br /> Port: Twisted Pair<br /> PHYAD: 0<br /> Transceiver: internal<br /> Auto-negotiation: on<br /> Supports Wake-on: pg<br /> Wake-on: d<br /> Current message level: 0x000000ff (255)<br /> Link detected: yes<br /> <br /> <br /> &lt;b&gt;Note&lt;/b&gt;: Link detected: yes.<br /> ** If this was &quot;no&quot;, you would want to physically inspect dev1&#039;s physical network connection. <br /> <br /> <br /> On my RHEL 7 instance:<br /> $ sudo ethtool eth0<br /> Settings for eth0:<br /> Current message level: 0x000004e3 (1251)<br /> drv probe ifup rx_err tx_err tx_done<br /> Link detected: yes<br /> <br /> <br /> &lt;b&gt;ethtool&lt;/b&gt; has uses beyond simply checking for a link. It can also be used to diagnose and correct duplex issues. When a Linux server connects to a network, typically it autonegotiates with the network to see what speeds it can use and whether the network supports full duplex. <br /> <br /> <br /> The &lt;b&gt;Speed&lt;/b&gt; and &lt;b&gt;Duplex&lt;/b&gt; lines in the example &lt;b&gt;ethtool&lt;/b&gt; output illustrate what a 100Mb/s, full duplex network should report. If you notice slow network speeds on a host, its speed and duplex settings are a good place to look. <br /> <br /> <br /> Run &lt;b&gt;ethtool&lt;/b&gt; as in the previous example, and if you notice &lt;b&gt;Duplex&lt;/B&gt; set to &lt;b&gt;Half&lt;/b&gt;, then run:<br /> $ sudo ethtool -s eth0 autoneg off duplex full<br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> ----<br /> <br /> <br /> References:<br /> [+] https://learning.oreilly.com/library/view/devops-troubleshooting-linux/9780133035513/ch05.html</div>

Ardika Sulistija