networking network_error ai_generated true

eth0: jumbo frame dropped, MTU 1500 but frame size 9000 received from 00:1a:2b:3c:4d:5e

ID: networking/ethernet-jumbo-frame-dropped

Also available as: JSON · Markdown · 中文
88%Fix Rate
83%Confidence
1Evidence
2024-01-30First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
Linux kernel 5.15 active — — —
Linux kernel 6.6 active — — —
FreeBSD 13.2 active — — —

Root Cause

A network interface configured with a standard 1500-byte MTU received an Ethernet frame larger than the MTU (a jumbo frame), typically from a peer that has jumbo frames enabled, causing the kernel to drop the frame due to size mismatch.

generic

中文

配置为标准1500字节MTU的网络接口接收到了大于MTU的以太网帧（巨帧），通常来自启用了巨帧的对端，导致内核因大小不匹配而丢弃该帧。

Official Documentation

https://www.kernel.org/doc/Documentation/networking/jumbo-frames.txt

Workarounds

  1. 90% success On the sender: ifconfig eth0 mtu 1500 
    On the sender: ifconfig eth0 mtu 1500
  2. 85% success ip link set dev eth0 mtu 9000 
    ip link set dev eth0 mtu 9000

中文步骤

  1. On the sender: ifconfig eth0 mtu 1500
  2. ip link set dev eth0 mtu 9000

Dead Ends

Common approaches that don't work:

  1. Setting the MTU on eth0 to 9000 to accept jumbo frames. 60% fail

    This may cause fragmentation issues if the path has other devices with lower MTU; also, it changes the interface's behavior for all traffic, not just the problematic peer.

  2. Using an access control list to block large frames from the sender. 80% fail

    Does not solve the root cause; the sender still sends jumbo frames, and blocking them drops legitimate traffic.