ethtool -s eth0 speed 1000 duplex full autoneg on

Category: Networking

ethtool -s eth0 speed 1000 duplex full autoneg on

Force interface speed, duplex, and autonegotiation

Overrides the NIC's autonegotiation. Duplex mismatch (one side full, other half) causes severe performance degradation — packets get sent simultaneously and collide. Usually only needed with old/legacy network equipment.
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