What Is an SMTP Server?In Feburary 2016 18,

In Feburary 2016 18,
Mail-delivery protocols began in the 1960s and continued to become more standardized as the number of hosts grew. SMTP was defined by Jon Postel in 1982 in the publication 'RFC821.' The current widely used standards are still essentially the same. Although many changes have been proposed to enhance security, the difficulties of implementing new standards universally have stopped changes from catching on.
Function
SMTP is the standard used to send emails from email clients on personal computers. It is commonly used in conjunction with POP or IMAP servers, which recieve mail. Most email clients, including Outlook, Entourage and Thunderbird, allow the use of SMTP.
Features
By default, SMTP uses plain ASCII text to communicate with a mail server on Port 25. SMTP servers can use secure-sockets layer connections for additional security. Some SMTP servers also require authentication with a user name and password.
Expert Insight
The lack of restrictions required for SMTP connections makes it possible to create emails with false information through a DOS command prompt. These can still be traced by authorities but can appear to come from incorrect sources. This is one reason spam emails are so prevalent.
Warning
Some Internet service providers block Port 25 to prevent spam and only allow their own SMTP servers to be used on their networks. In such cases, SMTP servers using other ports may still work, or the provider may allow the port to be opened upon request.
In Feburary 2016 18,

The Best Practices for Email Attachment SizeIn Feburary 2016 05,

In Feburary 2016 05,
There are many free email accounts provided by companies with a large Internet presence. These free email accounts include Hotmail, Yahoo! Mail and Gmail. Each free account limits the total attachment size for every email. Hotmail allows a maximum of 10MB to be attached to every email message. Yahoo allows 20MB and Gmail allows 25MB. Attachment sizes should work within each mail system's guidelines. Failure to do so will result in emails not being sent.
Encoding of Attachments
Free email accounts go through a process of encoding. This means that adjustments are made to the files so that other mail systems can read them. The result is adds an additional 33 percent to the original size of the files. Attachment limits provided by free email accounts also include the encoding.Example:
Yahoo Attachment Limit: 20MB
Attachment Size Before Coding on Yahoo: 15MB
Attachment Size After Coding: 20MBIn the above example, Yahoo limits attachments to a total size of 20MB. A file that is 15MB, after coding, is 20MB. In the case of Yahoo accounts, 15MB is the actual attachment limit.
Attachment Limits on Self-Hosting Accounts
Website owners that have accounts with Internet hosting companies also have access to email accounts. These email accounts can be accessed within the cpanel. The cpanel is also known as the control panel and all website additions and adjustments can be made from there.Email accounts through self-hosting companies also have limits on attachments. The size limit varies with each company. Go Daddy has a total attachment limit of 20MB per email, Bluehost has 10MB and Dreamhost has a limit of 40MB.
Understanding Receiving Limits
Even though some mail systems can send larger attachments than others, it isn’t the only factor that limits attachment size. Attachment limits depends on how much the recipient can receive. Example:
Gmail send limit: 25MB
Gmail receive limit: 25MB
Hotmail send limit: 10MB
Hotmail receive limit: 10MBIn the above example, a Gmail account sending to a Hotmail account cannot have an attachment size larger than 10MB. Even though a Gmail account can send 25MB, the email is limited by the recipient’s ability to receive attachments. On many mail systems, the receiving limit corresponds to the sending limit.In the above example, a Gmail account could send 25MB in some situations. This depends on the recipient also having a Gmail account or being able to receive 25MB.
Splitting Larger Files
Some files have sizes that exceed what is allowed by a mail system. One way to get around this is by using a program that will split the file (see Resources). The program takes a large file and splits it into several, smaller sizes. This allows a person to send a large file in smaller portions and to attach it on several emails. The person receiving the files would then re-merge the split files. Before the recipient receives a split file, they need to be informed before hand. If the recipient doesn't have the same file splitting software, they won't be able merge the files back together. Alternatively, the sender can use a compression or zipping program to shrink the file size and send it as an attachment. The recipient would then need to expand the attachment or zipped file.
In Feburary 2016 05,