ServerBuddies Support Blog

Scanning for Block Devices

You can scan for block devices that may be used as physical volumes with the lvmdiskscan
command, as shown in the following example.

Block an IP from access to your server with IPtable

Use the command netstat -n command to see the IP addresses connected to your server. Once you have found the IP address you want to block you can use the following below command to block them from accessing your server using iptables.

-I INPUT 1 means to insert the rule at the top of the INPUT table (which means it will get looked at first)

-s IP-ADDRESSS is the source address of the packets we want to deal with

-j DROP means dump the packets into the void, and forget they ever happened.

How to block a specific IP Address from accessing your Website

If you have annoying visitors, site scrapers, or spammers, you may find it useful to block these users from accessing your website content. You can block bad visitors by IP Address (or blocks of IP Addresses) using a .htaccess file. Below are some useful examples.

In the following example, all IP Addresses and domains are accepted, except for xxx.xxx.xxx.xxx and bad-site-example.com.

# allow all except those indicated here
<Files *>
order allow,deny
allow from all
deny from xxx.xxx.xxx.xxx
deny from .*bad-site-example\.com.*
</Files> 

In the following example, all IP addresses are denied access except for xxx.xxx.xxx.xxx and good-site-example.com.

# Deny access to everyone, except those listed here:
<Files *>
order deny,allow
deny from all
allow from xxx.xxx.xxx.xxx
allow from .*good-site-example\.com.*
</Files> 

Block IP Addresses With IPtables:

This command will simply drop any packet coming from the address 25.55.55.55. To list the chains:

The -n sticks with just IP addresses, rather than resolving the name. This is useful if you have a lot of IP addresses. It can take a lot of time to resolve all of the addresses.

If you later decide that you don’t want to drop packets from a particular host, use the -D option instead of -I:

Scanning for Block Devices

You can scan for block devices that may be used as physical volumes with the lvmdiskscan command, as shown in the following example.

lvmdiskscan scans all SCSI, (E)IDE disks, multiple devices and a bunch of other block devices in the system looking for LVM physical volumes. The size reported is the real device size. Define a filter in lvm.conf(5) to restrict the scan to avoid a CD ROM, for example.

If run as a user then.