HTML Color Codes and Hex Values

Why red, green, blue?

Remember your elementary school art lessons? The primary colors from which all other colors are derived are: red, yellow, blue (plus the shades of black and white).

In the world of TVs and computer monitors, however, the primary colors are red, green, and blue. The reason? In school we were taught the art of subtractive color mixing, wherease display monitors uses the process of additive mixing. By starting with red, green and blue, the color yellow can be created from the composite color, Green, which a combination of yellow and blue.

Other Useful Text/HTML Tools

Remove extra whitespace Tool

This tool removes multiple whitespace and tabs from text and replaces them with a single whitespace. It can also optionally delete all tabs or replace them with a single space.


Paste text in the box below, then press Execute. Results will appear in the bottom box.

Replace whitespaces with a single space and delete all tabs
Replace both multiple whitespaces and tabs with a single space


OUI Lookup Tool

Every MAC address contains an Organizationally Unique Identifier (OUI), which identifies the vendor of the device to which a MAC address is assigned. The OUI is the first 6 bytes (48 bits) of the MAC address. The remaining 6 bytes, represent a unique identifier for the specific device

This tool provides an quick way to find the OUIs of a MAC address. It uses the Wireshark manufacturer database, which is a list of OUIs and MAC addresses compiled from a number of sources.

Type or Paste in a list of OUIs or MAC addresses in the box below. The OUI or MAC addresses can be entered by using any of these examples:
Using OUI (or full MAC address) in any format: 0040.7f,00407f, 00:40:7f or 00-40-7f
Partial OUI: 0040 (returns all matching vendors)
Vendor Name eg: Toshiba (returns all OUIs assigned to the vendor).

INPUT OUI or Vendor


No matches

Useful toolbox for open relays, whois and more

Perform an Automated Test for Open Relays
Go to http://mxtoolbox.com/diagnostic.aspx.
In the Mail Server field, enter your server's IP address.
Click Test Email Server.
On the page that displays, receiving a message of Failed To Connect in the Results column of the SMTP Connect row means your relays are closed.
If you receive any other outputs, your relays are open.

Tool to check why a padlock is not displayed when using SSL