Installing GNOME on CentOS 6.4 minimal

If you installed CentOS 6.4 from CD-minimal, you don’t have GUI manager by default. To fix that, use below command 

yum groupinstall basic-desktop desktop-platform x11 fonts

Using startx command you can start GNOME now

To start automatically after you reboot your computer. Pl change default runlevel to 5 – replace id:3:initdefault: in /etc/inittab file with id:5:initdefault:

Super Tools

Some important tools and its meaning.

Command   Explaination
Blacklist: Check IP or host for reputation
SMTP: Test mail server SMTP (port 25)
MX:   DNS MX records for domain
A:   DNS A record IP address for host name
SPF:   Check SPF records on a domain
TXT: Check TXT records on a domain
PTR:   DNS PTR record for host name
CNAME: DNS canonical host name to IP address
SCAN: Perform a port scan on the host
WHOIS: Get domain registration information
ARIN:  Get IP address block information
SOA:  Get Start of Authority record for a domain
TCP: Verify an IP Address allows tcp connections
HTTP: Verify a URL allows http connections
HTTPS: Verify a URL allows secure http connections
PING:  Perform a standard ICMP ping
TRACE: Perform a standard ICMP trace route
DNS: Check your DNS Servers for possible problems