默认的系统一般都没有开启bbr网络加速，有时候网络不好的情况下更新系统都可能下载卡顿，因此新的Debian系统应该立即开启bbr网络加速。
方案1
cat > /etc/sysctl.conf << EOF
fs.file-max = 6815744
net.ipv4.tcp_no_metrics_save=1
net.ipv4.tcp_ecn=0
net.ipv4.tcp_frto=0
net.ipv4.tcp_mtu_probing=0
net.ipv4.tcp_rfc1337=0
net.ipv4.tcp_sack=1
net.ipv4.tcp_fack=1
net.ipv4.tcp_window_scaling=1
net.ipv4.tcp_adv_win_scale=1
net.ipv4.tcp_moderate_rcvbuf=1
net.core.rmem_max=33554432
net.core.wmem_max=33554432
net.ipv4.tcp_rmem=4096 87380 33554432
net.ipv4.tcp_wmem=4096 16384 33554432
net.ipv4.udp_rmem_min=8192
net.ipv4.udp_wmem_min=8192
net.ipv4.ip_forward=1
net.ipv4.conf.all.route_localnet=1
net.ipv4.conf.all.forwarding=1
net.ipv4.conf.default.forwarding=1
net.core.default_qdisc=fq
net.ipv4.tcp_congestion_control=bbr
net.ipv6.conf.all.forwarding=1
net.ipv6.conf.default.forwarding=1
EOF
sysctl -p && sysctl --system
执行完即可立即生效。
方案2
如果不放心也可以使用一键脚本来开启和检查状态
wget -N --no-check-certificate "https://raw.githubusercontent.com/chiakge/Linux-NetSpeed/master/tcp.sh"
chmod +x tcp.sh
./tcp.sh