Ethtool

ethtool command is used to view and modify network device drivers setting, in particular wired Ethernet devices.

ethtool -K eth0 gso off gro off tso off

ethtool -K eth0 gso on gro on tso on
Actual changes:
generic-segmentation-offload: on
generic-receive-offload: on

ethtool -K eno1 tx on rx on
Actual changes:
rx-checksumming: on
tx-checksumming: on
	tx-checksum-ip-generic: on
tcp-segmentation-offload: on 
	tx-tcp-segmentation: on 

tx-tcp-mangleid-segmentation: on tx-tcp6-segmentation: on

• Disable TCP checksum offloading

ethtool -K eth0 tx off rx off

ethtool --show-offload eno0

Examples

• ethtool eno1

 Settings for eno1:
 	Supported ports: [ TP ]
	Supported link modes:   10baseT/Half 10baseT/Full
	                        100baseT/Half 100baseT/Full
	                        1000baseT/Half 1000baseT/Full
	Supported pause frame use: No
	Supports auto-negotiation: Yes
	Supported FEC modes: Not reported
	Advertised link modes:  10baseT/Half 10baseT/Full
	                        100baseT/Half 100baseT/Full
	                        1000baseT/Half 1000baseT/Full
	Advertised pause frame use: Symmetric
	Advertised auto-negotiation: Yes
	Advertised FEC modes: Not reported
	Link partner advertised link modes:  10baseT/Half 10baseT/Full
	                                     100baseT/Half 100baseT/Full
	                                     1000baseT/Full
	Link partner advertised pause frame use: No
	Link partner advertised auto-negotiation: Yes
	Link partner advertised FEC modes: Not reported
	Speed: 1000Mb/s
	Duplex: Full
	Port: Twisted Pair
	PHYAD: 4
	Transceiver: internal
	Auto-negotiation: on
	MDI-X: off
	Supports Wake-on: g
	Wake-on: g
	Current message level: 0x000000ff (255)
			       drv probe link timer ifdown ifup rx_err tx_err
        Link detected: yes

ethtool eno1
Settings for eno1:
	Supported ports: [ TP ]
	Supported link modes:   10baseT/Half 10baseT/Full
	                        100baseT/Half 100baseT/Full
	                        1000baseT/Full
	Supported pause frame use: No
	Supports auto-negotiation: Yes
	Supported FEC modes: Not reported
	Advertised link modes:  10baseT/Half 10baseT/Full
	                        100baseT/Half 100baseT/Full
	                        1000baseT/Full
	Advertised pause frame use: No
	Advertised auto-negotiation: Yes
	Advertised FEC modes: Not reported
	Speed: 1000Mb/s
	Duplex: Full
	Port: Twisted Pair
	PHYAD: 1
	Transceiver: internal
	Auto-negotiation: on
	MDI-X: off (auto)
	Supports Wake-on: pumbg
	Wake-on: g
	Current message level: 0x00000007 (7)
			       drv probe link
	Link detected: yes

ethtool ens3f1
Settings for ens3f1:
	Supported ports: [ ]
	Supported link modes:   1000baseT/Full
	                        1000baseKX/Full
	                        10000baseT/Full
	                        1000baseX/Full
	                        10000baseSR/Full
	                        10000baseLR/Full
	Supported pause frame use: Symmetric
	Supports auto-negotiation: Yes
	Supported FEC modes: Not reported
	Advertised link modes:  1000baseT/Full
	                        1000baseKX/Full
	                        10000baseT/Full
	                        1000baseX/Full
	                        10000baseSR/Full
	                        10000baseLR/Full
	Advertised pause frame use: No
	Advertised auto-negotiation: Yes
	Advertised FEC modes: Not reported
	Speed: Unknown!
	Duplex: Unknown! (255)
	Port: Other
	PHYAD: 0
	Transceiver: internal
	Auto-negotiation: off
	Supports Wake-on: d
	Wake-on: d
	Current message level: 0x00000007 (7)
			       drv probe link
	Link detected: no

ethtool -i eno1
driver: e1000e
version: 3.2.6-k
firmware-version: 0.5-4
expansion-rom-version:
bus-info: 0000:00:1f.6
supports-statistics: yes
supports-test: yes
supports-eeprom-access: yes
supports-register-dump: yes
supports-priv-flags: no

Related terms

• ip link set eth0 up
• TCP Segmentation Offload (TSO)
• Generic Segmentation Offload (GSO)
• Generic Receive Offload (GRO)

See also

• TCP/IP, Transport protocol, UDP, SCTP, QUIC, subnet mask, Routing protocols: BGP, routing table, Policy based routing, multicast, TCP Fast Open, RDP, TTL, RTT, MPTCP, Large send offload (LSO): (TSO, GRO, GSO, TCP checksum), ethtool, SCTP, 5-Tuple, Check TCP connectivity, TCP window size, /proc/sys/net/ipv4/tcp_rmem, ack, List of TCP ports, localhost, broadcast address
• ifconfig, ethtool or obsolete mii-tool (mii-tool -v eth0) nmcli device show, eth0, Network manager
• MII: mii-tool, ethtool, MDI, RGMII, SGMII, GMII, SFI, XFI, XAUI, SerDes
• Ethernet: MII, MDI, bonding, etherchannel, STP, ARP, MAC, STP, Jumbo frames, 802.1X, MTU, Ethernet In-Band Access (IBA), LACP, Multicast, Broadcast, SPI

http://man7.org/linux/man-pages/man8/ethtool.8.html