ethtool(8)
Display and change ethernet device settings including speed, duplex, autonegotiation, and driver statistics.
Synopsis
ethtool [-a|-c|-C|-g|-G|-i|-d|-e|-E|-k|-K|-p|-r|-S|-t|-T|-x|-X] DEVNAMEDescription
ethtool is used to query and control network device driver and hardware settings. It can display link speed, duplex mode, autonegotiation status, and modify these settings. It also provides access to driver statistics, EEPROM contents, and self-test capabilities.
Most operations require root privileges. Common uses include checking link speed, enabling/disabling features like offloading, and troubleshooting network performance issues.
Common options
| Flag | What it does |
|---|---|
-a | Show all device features (pause, offloading, etc.) |
-c | Show coalescing settings (interrupt moderation) |
-C | Change coalescing parameters (requires root) |
-g | Show ring buffer sizes (RX/TX) |
-G | Change ring buffer sizes (requires root) |
-i | Show driver and firmware information |
-k | Show offload features status (TSO, GRO, LRO, etc.) |
-K | Change offload features (requires root) |
-p | Identify the device by blinking LED |
-r | Restart autonegotiation |
-S | Show detailed driver statistics |
-t | Run device self-tests |
Examples
Display current settings for eth0: speed, duplex, autonegotiation status
ethtool eth0Show driver name, version, and firmware version for eth0
ethtool -i eth0View ethernet statistics and filter for dropped packet counts
ethtool -S eth0 | grep -i droppedDisable TCP Segmentation Offload and Generic Segmentation Offload (root required)
sudo ethtool -K eth0 tso off gso offShow which offload features are enabled/disabled on the device
ethtool -k eth0Display interrupt coalescing settings (how often interrupts are fired)
ethtool -c eth0Restart autonegotiation to renegotiate link speed and duplex (root required)
sudo ethtool -r eth0Show current and maximum RX/TX ring buffer sizes
ethtool -g eth0