|Stands for Simple Mail Transfer Protocol||Stands for Extended Simple Mail Transfer Protocol|
|First command in SMTP session: |
|First command in ESMTP session: |
|RFC 821||RFC 1869|
|SMTP ‘MAIL FROM’ and “RCPT TO’ allows size only of 512 characters including <CRLF>. ||ESMTP ‘MAIL FROM’ and “RCPT TO’ allows size greater than 512 characters.|
|SMTP alone cannot be extended with new commands.||ESMTP is framework that enhances capability to extend existing SMTP commands|
If you are aware of any improvements to above differences or want to add to the above list then please post your comments below.