If you need to send emails anonymously you have various options: you can do so through a proxy, use Open Relay servers and, maybe the easiest, use an application like Anonymail.
Massive emails without revealing your identity
By means of this program, we will be able to manage massive mailing through the usual SMTP servers, while hiding the IP from which they have been sent, as well as hiding any other personal information. Due to this, it is a tool that is very useful to launch spam and perform publicity campaigns.
The main advantage of Anonymail is its capacity to keep the sender's identity hidden. Even though it also stands out due to how easy it is to use and the possibility to automatically send a large number of emails per minute: nearly 10,000!
Other features of this utility are the sending of customized messages (even in HTML format), adding attachments, the scarce amount of computer resources and Internet bandwidth that it uses... Anonymail is the most practical and efficient tool to send emails anonymously.