About IP Addresses

In the world wide web, the millions of computers and computerized devices communicate with each other using IP (Internet protocol) addresses. These are a combination of numbers that are unique to each Internet connection or computer, depending on the complexity of the network through which the computer gets the Internet connection.

SPF (Sender Policy Framework), is a system that authenticates and identifies servers that your domain can use to send mail. The aim is to ensure that unauthorized spammers and cyber criminals do not send messages to recipients that supposedly come from your domain. With SPF in place, recipients can check the available records to determine whether the received e-mails originated from an authorized mail server. Keep reading to learn more about the sender policy framework.

SPF Versus Sender ID

Contrary to popular belief, SPF and sender ID is quite different. The confusion stems from the fact that both use the same policy records syntax, validate e-mail sender addresses, and publish policy records in DNS. However, this is where the similarity ends. SPF validates two parts of the e-mail sender's address: the MAIL FROM address and the HELO domain. You can find this information by checking the records published by domain owners. It is important to note that both the HELO domain and the MAIL FROM are part of the SMTP protocol. On the other hand, sender ID is a Microsoft protocol that validates a single field of the e-mail address header. The header to validate depends on the choice made by the Purported Responsible Address (PRA) algorithm.

As more people use mobile devices, the need for your website to have a responsive design becomes a necessity. What’s a mobile responsive design? You might ask. It’s the theme including layout and content that adapts to the size of the screen. So, if you will try to visit Facebook on your iPhone’s Safari or Google Chrome browser, you’ll notice that the content shifts to fit the display of your device’s screen.

Since smartphones and tablets have smaller screens than laptops and PCs, websites without responsive design may take a longer time to load considering it’s made up of Flash images, longer content and full-HD background. If your website doesn’t have a responsive design, then you are losing a lot of clients. In fact, 60 percent of mobile users will only wait three seconds for a page to load. The study also revealed that 43 percent of the respondents said they are unlikely to return to a slow loading site. So far, 77 percent of the mobile sites take more than five seconds to load, so make sure you know how to measure your website’s response time.

When a web server receives a request, it returns an HTTP (Hypertext Transfer Protocol) status code in response to the request. An HTTP request may fail as a result of a network error or when the web server experiences problems executing a request. Consequently, the server returns a corresponding HTTP status code to describe the condition of the request. The status codes help in identifying the cause of the problem when a web resource fails to load properly.

The 5xx codes are Server Error codes indicating that an error has occurred while processing the client’s request.

The 4xx HTTP status codes are purposed to indicate what you or your client agent may have done wrong. In any case, your client agent is required to display the error to you especially when it is related to your actions. When a HEAD request is submitted, the server does not display the error code. Instead, it acts on the request.

400 - Bad Request

This is normally due to erred syntax or inclusion of characters that the server would not understand. This request will be displayed for your purposeful response.