What is a third party relay email server ?
A third party mail relay is an email server receiving email from an unknown sender and then sending it on to a recipient or recipients that are not users of that email system. Some email systems enable this relay feature in the default installation. Taking into account the large number of mail servers that exist on the Internet, this is still a considerable number of servers which allow the relay. Spammers can simply collect lists of third party mail relay in the Internet through some scanning programs. With the lists, spammers can configure the spamming tool with a relay’s address, so it obscures their identity from the recipients and places the burden of the work on an email server that they don’t worry about overloading or crashing.
