开启 bbr
修改内核参数

echo "net.core.default_qdisc=fq" >> /etc/sysctl.conf
echo "net.ipv4.tcp_congestion_control=bbr" >> /etc/sysctl.conf

sysctl -p

检查内核 bbr 状态

sysctl net.ipv4.tcp_available_congestion_control

如显示以下内容则说明开启成功:

net.ipv4.tcp_available_congestion_control = reno cubic bbr
检查 bbr 启动状态

lsmod | grep bbr

如显示以下内容则说明启动成功:

tcp_bbr 20480 1
修改 apt 源
备份现有源

mv /etc/apt/sources.list /etc/apt/sources.list.bak

替换为 Debian 官方源

cat > /etc/apt/sources.list << EOF
deb https://deb.debian.org/debian/ bullseye main contrib non-free
deb-src https://deb.debian.org/debian/ bullseye main contrib non-free
deb https://deb.debian.org/debian/ bullseye-updates main contrib non-free
deb-src https://deb.debian.org/debian/ bullseye-updates main contrib non-free
deb https://deb.debian.org/debian/ bullseye-backports main contrib non-free
deb-src https://deb.debian.org/debian/ bullseye-backports main contrib non-free
deb https://deb.debian.org/debian-security/ bullseye-security main contrib non-free
deb-src https://deb.debian.org/debian-security/ bullseye-security main contrib non-free
EOF

替换为阿里云源

cat > /etc/apt/sources.list << EOF
deb https://mirrors.aliyun.com/debian/ bullseye main non-free contrib
deb-src https://mirrors.aliyun.com/debian/ bullseye main non-free contrib
deb https://mirrors.aliyun.com/debian-security/ bullseye-security main
deb-src https://mirrors.aliyun.com/debian-security/ bullseye-security main
deb https://mirrors.aliyun.com/debian/ bullseye-updates main non-free contrib
deb-src https://mirrors.aliyun.com/debian/ bullseye-updates main non-free contrib
deb https://mirrors.aliyun.com/debian/ bullseye-backports main non-free contrib
deb-src https://mirrors.aliyun.com/debian/ bullseye-backports main non-free contrib
EOF

替换腾讯云源

cat > /etc/apt/sources.list << EOF
deb https://mirrors.tencent.com/debian/ bullseye main non-free contrib
deb-src https://mirrors.tencent.com/debian/ bullseye main non-free contrib
deb https://mirrors.tencent.com/debian-security/ bullseye-security main
deb-src https://mirrors.tencent.com/debian-security/ bullseye-security main
deb https://mirrors.tencent.com/debian/ bullseye-updates main non-free contrib
deb-src https://mirrors.tencent.com/debian/ bullseye-updates main non-free contrib
deb https://mirrors.tencent.com/debian/ bullseye-backports main non-free contrib
deb-src https://mirrors.tencent.com/debian/ bullseye-backports main non-free contrib
EOF

如果是阿里云或者腾讯云的机器还可以使用内网源。

阿里云内网源

cat > /etc/apt/sources.list << EOF
deb http://mirrors.cloud.aliyuncs.com/debian/ bullseye main contrib non-free
deb-src http://mirrors.cloud.aliyuncs.com/debian/ bullseye main contrib non-free
deb http://mirrors.cloud.aliyuncs.com/debian/ bullseye-updates main contrib non-free
deb-src http://mirrors.cloud.aliyuncs.com/debian/ bullseye-updates main contrib non-free
deb http://mirrors.cloud.aliyuncs.com/debian/ bullseye-backports main contrib non-free
deb-src http://mirrors.cloud.aliyuncs.com/debian/ bullseye-backports main contrib non-free
deb http://mirrors.cloud.aliyuncs.com/debian-security/ bullseye-security main contrib non-free
deb-src http://mirrors.cloud.aliyuncs.com/debian-security/ bullseye-security main contrib non-free
EOF

腾讯云内网源

cat > /etc/apt/sources.list << EOF
deb http://mirrors.tencentyun.com/debian/ bullseye main contrib non-free
deb-src http://mirrors.tencentyun.com/debian/ bullseye main contrib non-free
deb http://mirrors.tencentyun.com/debian/ bullseye-updates main contrib non-free
deb-src http://mirrors.tencentyun.com/debian/ bullseye-updates main contrib non-free
deb http://mirrors.tencentyun.com/debian/ bullseye-backports main contrib non-free
deb-src http://mirrors.tencentyun.com/debian/ bullseye-backports main contrib non-free
deb http://mirrors.tencentyun.com/debian-security/ bullseye-security main contrib non-free
deb-src http://mirrors.tencentyun.com/debian-security/ bullseye-security main contrib non-free
EOF
* 注：可以通过注释掉 deb-src 源来提高速度。