初次使用Debian系统呢，上来我们一般要先执行这些操作，更新源或者更换源，删除无用的端口占用服务，还我们一个干净的系统，以下自己的一些使用教程，顺便记录下笔记。
升级源软件包：
apt update && apt install wget curl nano screen git -y
#或者
apt update && apt upgrade -y查看源
cat /etc/apt/sources.list一键更改源为163
echo 'deb http://mirrors.163.com/debian/ buster main non-free contrib
deb http://mirrors.163.com/debian/ buster-updates main non-free contrib
deb http://mirrors.163.com/debian/ buster-backports main non-free contrib
deb-src http://mirrors.163.com/debian/ buster main non-free contrib
deb-src http://mirrors.163.com/debian/ buster-updates main non-free contrib
deb-src http://mirrors.163.com/debian/ buster-backports main non-free contrib
deb http://mirrors.163.com/debian-security/ buster/updates main non-free contrib
deb-src http://mirrors.163.com/debian-security/ buster/updates main non-free contrib
' > /etc/apt/sources.list手动更改
vim /etc/apt/sources.list163源
deb http://mirrors.163.com/debian/ buster main non-free contrib
deb http://mirrors.163.com/debian/ buster-updates main non-free contrib
deb http://mirrors.163.com/debian/ buster-backports main non-free contrib
deb-src http://mirrors.163.com/debian/ buster main non-free contrib
deb-src http://mirrors.163.com/debian/ buster-updates main non-free contrib
deb-src http://mirrors.163.com/debian/ buster-backports main non-free contrib
deb http://mirrors.163.com/debian-security/ buster/updates main non-free contrib
deb-src http://mirrors.163.com/debian-security/ buster/updates main non-free contrib腾讯源
deb http://mirrors.cloud.tencent.com/debian/ buster main non-free contrib
deb http://mirrors.cloud.tencent.com/debian-security buster/updates main
deb http://mirrors.cloud.tencent.com/debian/ buster-updates main non-free contrib
deb http://mirrors.cloud.tencent.com/debian/ buster-backports main non-free contrib
deb-src http://mirrors.cloud.tencent.com/debian-security buster/updates main
deb-src http://mirrors.cloud.tencent.com/debian/ buster main non-free contrib
deb-src http://mirrors.cloud.tencent.com/debian/ buster-updates main non-free contrib
deb-src http://mirrors.cloud.tencent.com/debian/ buster-backports main non-free contrib一键改为默认源
echo 'deb http://deb.debian.org/debian/ stretch main
deb-src http://deb.debian.org/debian/ stretch main
deb http://security.debian.org/debian-security stretch/updates main
deb-src http://security.debian.org/debian-security stretch/updates main
# stretch-updates, previously known as 'volatile'
deb http://deb.debian.org/debian/ stretch-updates main
deb-src http://deb.debian.org/debian/ stretch-updates main
' > /etc/apt/sources.listdebian防火墙介绍：
https://www.lanbu.net/d/82
删除无用服务
debian8版本莫名其妙会有很多的端口占用，这让我看着有点非常不爽，查了些资料，终于找到了些解决办法，现在分享给大家。
删除 exim4 服务
exim4服务 开放 port :25 大家都知道这个端口做啥都吧！
systemctl stop exim4
systemctl disable exim4
apt-get purge --auto-remove exim4 exim4-base exim4-config exim4-daemon-light
rm -rf /var/log/exim4/删除 rpcbind 服务
rpcbind 服务 此服务开启port :111 这个端口。
systemctl stop rpcbind
systemctl disable rpcbind
apt-get purge --auto-remove rpcbind删除nfs服务
systemctl stop nfs-common
systemctl disable nfs-common
apt-get purge --auto-remove nfs-kernel-server nfs-common portmap以上这些都是本人从centos转到debian遇到的坑。
