來源： [Linux][Ubuntu] Ubuntu 16.04 安裝LAMP PHP7 , Apache2 , MaraiDB « 老人的網路筆記

# clean all rules
iptables -F
iptables -t nat -F
iptables -X
iptables -Z

#default chain
iptables -P INPUT DROP
iptables -P OUTPUT ACCEPT
iptables -P FORWARD ACCEPT
iptables -t nat -P  PREROUTING ACCEPT
iptables -t nat -P      OUTPUT ACCEPT
iptables -t nat -P POSTROUTING ACCEPT

iptables -A INPUT -s 10.0.0.0/8 -p tcp --dport 22 -j ACCEPT
iptables -A INPUT -p tcp --dport 22 -j ACCEPT

#modify rule below this line
iptables -t nat -A PREROUTING -p tcp --dport 80 -j DNAT --to-destination 10.140.0.3:80
iptables -t nat -A PREROUTING -p tcp --dport 3389 -j DNAT --to-destination 10.140.0.3:3389
iptables -t nat -A POSTROUTING -j MASQUERADE

iptables -L -n -t nat

apt-get install software-properties-common python-software-properties

來源： Ubuntu Missing add-apt-repository command

I’ve recently being doing some work to set up LibreNMS to monitor our vast swath of internal switches and systems.

來源： Install Smokeping on Ubuntu 14.04 – Oliver Marshall

This tutorial shows you how to fix 504 gateway Timeout on Nginx

來源： How To Fix 504 Gateway Time-out on Nginx – idroot

Linux服务器通常需要远程登录访问，尤其是当服务器或VPS还允许root直接登录时，应该为SSH登录成功配置一个自动的email提醒。

sendmail直接发送的话很可能会发送到垃圾邮箱里，需要把地址加入到白名单。

把下面的admin@hackhp.com更改为你要接收登录通知的电子邮件地址。

CentOS

vim ~/.bash_profile

IP="$(echo $SSH_CONNECTION | cut -d " " -f 1)"
HOSTNAME=$(hostname)
NOW=$(date +"%e %b %Y, %a %r")

echo 'Someone from '$IP' logged into '$HOSTNAME' on '$NOW'.' | mail -s 'SSH Login Notification' admin@hackhp.com

Ubuntu/Debian

vim ~/.bashrc

IP="$(echo $SSH_CONNECTION | cut -d " " -f 1)"
HOSTNAME=$(hostname)
NOW=$(date +"%e %b %Y, %a %r")

echo 'Someone from '$IP' logged into '$HOSTNAME' on '$NOW'.' | mail -s 'SSH Login Notification' admin@hackhp.com

如果不想接收到邮箱，只想重定向到一个文件的话。

IP="$(echo $SSH_CONNECTION | cut -d " " -f 1)"
HOSTNAME=$(hostname)
NOW=$(date +"%e %b %Y, %a %r")
echo 'Someone from '$IP' logged into '$HOSTNAME' on '$NOW'.' >>/root/login.txt

Step One—Install Deny Hosts

We need to use a repository to install Deny Hosts on CentOS.

sudo rpm -Uvh http://mirror.metrocast.net/fedora/epel/6/i386/epel-release-6-8.noarch.rpm

sudo yum install denyhosts

Once the program has finished downloading to the VPS, denyhosts is installed and configured.

yum install denyhosts

http://blogger.liaohaha.tw/2012/02/denyhosts.html