拿到服务器的操作

1. sudo su -
2. 

useradd haha -m -s /bin/bash

3. passwd haha
4. usermod -a -G sudo haha
5.  deluser oleusername sudo
6. visudo
add following line under "root    ALL=(ALL:ALL) ALL"
haha  ALL=(ALL:ALL) ALL

7. log out, and log in.

deluser --remove-home olduser

1.  echo "nameserver 8.8.8.8" > /etc/resolv.conf
echo "hostname" >  /etc/hostname
1.1 vim /etc/hosts
change hostname;
1.2 vim /etc/rc.local
add following line:
echo "nameserver 8.8.8.8" > /etc/resolv.conf
save and quit;
2. vim /etc/network/interfaces
change ip address and gateway
3.  vim /etc/ssh/sshd_config
change port to 1234
4. reboot server
5. Configure Iptables

iptables -L

iptables -A INPUT -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT

 iptables -A INPUT -p tcp --dport *1234* -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j ACCEPT

iptables -A INPUT -j DROP 

iptables -I INPUT 1 -i lo -j ACCEPT

iptables -I INPUT 5 -m limit --limit 5/min -j LOG --log-prefix "iptables denied: " --log-level 7
6. Save iptables configuration
iptables-save > /etc/iptables.rules
7. Configure iptables save automatically
vim  vim /etc/network/interfaces
add following content:
pre-up iptables-restore < /etc/iptables.rules

save and quit.

apt-get update

apt-get upgrade