Category: Linux

  • Install MongoDB on CentOS 7

    To find latest MongoDB version, see

    https://docs.mongodb.com/manual/release-notes/

    To install MongoDB 3.6 on CentOS 7, create file

    vi /etc/yum.repos.d/mongodb-org-3.6.repo

    Add

    [mongodb-org-3.6]
name=MongoDB Repository
baseurl=https://repo.mongodb.org/yum/redhat/$releasever/mongodb-org/3.6/x86_64/
gpgcheck=1
enabled=1
gpgkey=https://www.mongodb.org/static/pgp/server-3.6.asc

    Refer https://docs.mongodb.com/master/tutorial/install-mongodb-on-red-hat/

    Now install MongoDB with 

    yum install mongodb-org

    Enable MongoDB start on boot with

    systemctl enable MongoDB

    To start MongoDB, run

    systemctl start mongod

    You can check status of MongoDB with

    systemctl status mongod

    MongoDB

  • How to restore R1Soft Backup

    How to restore R1Soft Backup

    To restore backup, login to R1Soft Server Backup Manager. Go to Protected Machines. This page will list all available servers.

    Restore backup in r1soft

    Click on wheel icon on right side.

    Click “Open Recovery Points” in the pop up menu. You get a new window with all available recovery points.

    Click on the wheel icon.

    In the popup menu, you will see “Browse” and “Bare Metal Restore”.

    Bare Metal Restore

    This is useful when you need to restore a server as is. Everything get restored exactly like in your old server. But only possible if you have physical access to server.

    Download backup files

    Browse option allow you to browse files and restore files and folders.

    You can go inside a folder by double clicking the folder name. To download a folder or file as compressed file, click the download icon on right side.

    Restore on same server

    You can restore a file on same server. This will replace existing files on the server with files from backup. Always take a copy of the files before you do this.

  • Install GeoIP Apache Module in CentOS

    To install GeoIP Apache module on CentOS 7, run

    yum -y install GeoIP GeoIP-devel GeoIP-data
yum -y install mod_geoip

    Now you need to configure Apache VirtualHost.

    To block traffic, add following to your VirtualHost entry

    RewriteEngine On
RewriteCond %{ENV:GEOIP_COUNTRY_CODE} ^(CN|RU|A1)$
RewriteRule ^(.*)$ https://serverok.in [L]

    In this example, traffic from CN, RU and A1 (stands for proxy IP) get redirected to specified URL.

    geoip

  • php-fpm

  • timezone

    To get list of all available timezones, run

    timedatectl list-timezones

    Example

    # timedatectl list-timezones | grep -i kolka
Asia/Kolkata
#

    You can use the following command to set the timezone

    timedatectl set-timezone EST

    Example

    timedatectl set-timezone EST
timedatectl set-timezone UTC
timedatectl set-timezone America/New_York
timedatectl set-timezone Asia/Kolkata

    To set the timezone in Ubuntu, run

    dpkg-reconfigure tzdata

    /etc/localtime

    For GMT

    ln -sf /usr/share/zoneinfo/GMT /etc/localtime

    For EST

    ln -sf /usr/share/zoneinfo/EST /etc/localtime

    Back to time

  • sendy

    Sendy cronjob

    */5 * * * * /usr/bin/curl --silent https://URL/scheduled.php  &> /var/log/sendy.log

    Or

    */5 * * * * /usr/bin/php /var/www/html/scheduled.php > /dev/null 2>&1
*/2 * * * * /usr/bin/php /var/www/html/import-csv.php > /dev/null 2>&1

    if you are installing as user root, run cronjob as web server user.

    On Ubuntu

    crontab -e -u www-data

  • fail2ban

    fail2ban-client status

    To install fail2ban on Deban/Ubuntu, run

    apt install fail2ban -y

  • Install fail2ban on CentOS

    To install fail2ban on CentOS, first, enable the epel repo by running

    yum install epel-release -y

    Now install fail2ban with

    yum install fail2ban -y

    Enable fail2ban with

    systemctl enable fail2ban

    Basck to fail2ban

  • Installing OpenSSH from Source on Ubuntu 16.04

    PCI Compliance report from COMMODO complain about OpenSSH version available in Ubuntu 16.04.

    SSH-2.0-OpenSSH_7.2p2 Ubuntu-4ubuntu2.4

    This version have all security updates back ported. Installing OpenSSH from source is bad idea as you have to manually upgrade to latest version when new version is released.

    Since PCI Compliance require new version of OpenSSH, i installed from source. It is better to LIMIT SSH access to your own IP using firewall or hosts.allow/deny rules.

    Install requirements

    apt update && apt install -y build-essential libssl-dev zlib1g-dev

    Go to

    https://www.openssh.com/portable.html

    Download latest version of OpenSSH source code from one of the mirrors.

    Download and install with

    cd /usr/local/src
wget https://cloudflare.cdn.openbsd.org/pub/OpenBSD/OpenSSH/portable/openssh-7.6p1.tar.gz
tar -zxvf openssh-7.6p1.tar.gz
cd /usr/local/src/openssh-7.6p1
make clean && make distclean
./configure --prefix=/usr
make
make install

  • htpasswd

    Create a password file

    htpasswd -c /path/to/passwd/file admin

    To change the password for an existing user

    htpasswd /path/to/passwd/file  USER_HERE

    You can use -b option to specify the password as a command line option, this is useful for adding or updating users non-interactively.

    htpasswd -b -c /path/to/passwd/file USER_HERE PASSWORD_HERE

    To limit access, add the following to the Apache virtual host entry.

    <Directory "/var/www/html">
    AuthType Basic
    AuthName "Restricted Content"
    AuthUserFile /path/to/passwd/file
    Require valid-user
</Direcory>
    




    Apache
    

    
			
    
		
    
		
	
  • 
		
		
    
			
			
    api
    
			
    Testing API
    

    https://extendsclass.com/rest-client-online.html
    

    https://insomnia.rest/
    

    https://www.getpostman.com/
    

    
			
    
		
    
		
	
  • 
		
		
    
			
			
    DDoS
    
			
    

    DDoS Protection Service
    Apache Website not loading – DDoS
    




    To check if your server is getting DDoS, you can use netstat command.
    




    netstat -anp | grep 'tcp' | awk '{print $5}' | cut -d: -f1 | sort| uniq -c | sort -n
    




    Or
    




    netstat -lantp|egrep ":80 "|awk '{print $5}'|cut -d: -f1|sort|uniq -c|sort -nr|head
netstat -ntu | awk '{print $5}' | cut -d: -f1 | sort | uniq -c | sort -n
netstat -alpn | grep :80 | awk '{print $4}' |awk -F: '{print $(NF-1)}' |sort | uniq -c | sort -n
    




    Instead of netstat, you can also use ss command
    




    ss -tan state established | grep ":80\|:443" | awk '{print $4}' | cut -d':' -f1 | sort -n | uniq -c | sort -n
    




    Once you find the offending IP address, you can block it in the firewall.
    




    To Verify if an IP is blocked
    




    iptables -L -n | grep 'IP_ADDR_HERE'
    




    Block Attack with CSF firewall
    




    vi /etc/csf/csf.conf
    




    Set CT_LIMIT to 30, set it back to 100 after attack stop.
    




    CT_LIMIT = "30"
    




    Set SYNFLOOD to 1, set it back to 0 after DDoS attack stop.
    




    SYNFLOOD = "1"