帮助中心连接问题针对慢速或分片连接的 MTU 设置
连接问题

针对慢速或分片连接的 MTU 设置

3 分钟 阅读·更新于 April 5, 2026

调整 MTU 可以解决 VPN 隧道中的速度缓慢和数据包分片问题。

MTU (Maximum Transmission Unit) defines the largest packet size that can be sent through a network. VPN encryption overhead can cause packets to exceed the network's MTU, causing fragmentation and slowdowns.

# Windows — find optimal MTU (Command Prompt, run as admin)
ping -f -l 1400 8.8.8.8
# Decrease size until you stop seeing "Packet needs to be fragmented"
# Optimal MTU = last working size + 28
  1. 1Go to Settings → Advanced → MTU
  2. 2Change from "Auto" to "Manual"
  3. 3Enter the value you calculated (typically 1280–1420)
  4. 4Click Save and reconnect

Start with 1300 if unsure — this works for most connections. UDP mode typically needs an MTU of 1420 or lower.

mtuslowpacket lossoptimizationadvanced

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