cloudcone ipv6的MTU有问题，尽快自行修改

先说结论 ： IPV6的MTU需要设置到1400..

========== IPv6 当前状态测试 ==========



测试 IPv6，当前 MTU：1500

Get:1 http://security.debian.org/debian-security trixie-security/main amd64 linux-libc-dev all 6.12.95-1 [2,852 kB]

Err:1 http://security.debian.org/debian-security trixie-security/main amd64 linux-libc-dev all 6.12.95-1

  Connection timed out [IP: 2a04:4e42:200::644 80]

E: Failed to fetch http://security.debian.org/debian-security/pool/updates/main/l/linux/linux-libc-dev_6.12.95-1_all.deb  Connection timed out [IP: 2a04:4e42:200::644 80]

[FAIL] IPv6 下载失败，退出码 100，大小 0 字节



========== 开始测试不同 MTU ==========



临时测试 MTU 1480



测试 IPv6，当前 MTU：1480

Get:1 http://security.debian.org/debian-security trixie-security/main amd64 linux-libc-dev all 6.12.95-1 [2,852 kB]

Err:1 http://security.debian.org/debian-security trixie-security/main amd64 linux-libc-dev all 6.12.95-1

  Connection timed out [IP: 2a04:4e42:600::644 80]

E: Failed to fetch http://security.debian.org/debian-security/pool/updates/main/l/linux/linux-libc-dev_6.12.95-1_all.deb  Connection timed out [IP: 2a04:4e42:600::644 80]

[FAIL] IPv6 下载失败，退出码 100，大小 0 字节



测试 IPv6，当前 MTU：1450

Get:1 http://security.debian.org/debian-security trixie-security/main amd64 linux-libc-dev all 6.12.95-1 [2,852 kB]

Err:1 http://security.debian.org/debian-security trixie-security/main amd64 linux-libc-dev all 6.12.95-1

  Connection timed out [IP: 2a04:4e42:200::644 80]

E: Failed to fetch http://security.debian.org/debian-security/pool/updates/main/l/linux/linux-libc-dev_6.12.95-1_all.deb  Connection timed out [IP: 2a04:4e42:200::644 80]

[FAIL] IPv6 下载失败，退出码 100，大小 0 字节



临时测试 MTU 1420



测试 IPv6，当前 MTU：1420

Get:1 http://security.debian.org/debian-security trixie-security/main amd64 linux-libc-dev all 6.12.95-1 [2,852 kB]

Err:1 http://security.debian.org/debian-security trixie-security/main amd64 linux-libc-dev all 6.12.95-1

  Connection timed out [IP: 2a04:4e42:600::644 80]

E: Failed to fetch http://security.debian.org/debian-security/pool/updates/main/l/linux/linux-libc-dev_6.12.95-1_all.deb  Connection timed out [IP: 2a04:4e42:600::644 80]

[FAIL] IPv6 下载失败，退出码 100，大小 0 字节



临时测试 MTU 1400



测试 IPv6，当前 MTU：1400

Get:1 http://security.debian.org/debian-security trixie-security/main amd64 linux-libc-dev all 6.12.95-1 [2,852 kB]

Fetched 2,852 kB in 0s (30.7 MB/s)       

[OK] IPv6 下载成功，大小 2852492 字节



测试 IPv6，当前 MTU：1400

Get:1 http://security.debian.org/debian-security trixie-security/main amd64 linux-libc-dev all 6.12.95-1 [2,852 kB]

Fetched 2,852 kB in 0s (19.0 MB/s)       

[OK] IPv6 下载成功，大小 2852492 字节



[OK] IPv6 在 MTU 1400 下连续测试成功

[OK] 已将 MTU 1400 写入 /etc/network/interfaces



    

  

========== IPv4 基准测试 ==========



测试 IPv4，当前 MTU：1400

Get:1 http://security.debian.org/debian-security trixie-security/main amd64 linux-libc-dev all 6.12.95-1 [2,852 kB]

Fetched 2,852 kB in 0s (30.1 MB/s)       

[OK] IPv4 下载成功，大小 2852492 字节



========== IPv6 当前状态测试 ==========



测试 IPv6，当前 MTU：1400

Get:1 http://security.debian.org/debian-security trixie-security/main amd64 linux-libc-dev all 6.12.95-1 [2,852 kB]

Fetched 2,852 kB in 0s (30.8 MB/s)       

[OK] IPv6 下载成功，大小 2852492 字节



测试 IPv6，当前 MTU：1400

Get:1 http://security.debian.org/debian-security trixie-security/main amd64 linux-libc-dev all 6.12.95-1 [2,852 kB]

Fetched 2,852 kB in 0s (28.0 MB/s)       

[OK] IPv6 下载成功，大小 2852492 字节

[OK] IPv6 连续两次下载成功，无需降低 MTU



    

  

官方邮件也是建议1400