Method and apparatus for transferring messages between realms on a network

A method of operating a message transfer agent in a network domain, the method comprising:

• receiving, at the message transfer agent, an email communication transmitted over a network, the email communication having an envelope containing a recipient address, the recipient address indicating an intended recipient of the email communication, the email communication further having a set of headers;
• determining whether the message transfer agent is associated with a realm of the intended recipient;
• and
• if the message transfer agent is not associated with the realm of the intended recipient, then relaying the communication within said network domain to a message transfer agent associated with the realm of the intended recipient, without altering the recipient address.

A method of operating a message transfer agent on a network, the method comprising:

• receiving, at the message transfer agent, an email communication transmitted over the network, the email communication having a recipient address indicating an intended recipient of the email communication;
• identifying a realm of the intended recipient from a plurality of realms defined within a single network domain;
• determining whether the message transfer agent is in the realm of the intended recipient;
• if the message transfer agent is in the realm of the intended recipient, then storing the communication in a message store server associated with the message transfer agent;
• and
• if the message transfer agent is not in the realm of the intended recipient, then
• identifying a message transfer agent in the realm of the intended recipient within said network domain, and
• relaying the communication within said network domain to the message transfer agent in the realm of the intended recipient, without altering the recipient address of the communication.

A method of operating a message transfer agent operating within a single network domain on a network, the method comprising:

• receiving, at the message transfer agent, an email communication transmitted over the network, the email communication having an envelope containing a recipient address indicating an intended recipient of the email communication;
• accessing account data for the intended recipient in a database which stores a set of account data for each of a plurality of users, each set of account data including a realm attribute specifying a realm, associated with the corresponding user, of a plurality of realms defined within the single network domain;
• using the realm attribute of the intended recipient to identify a realm of the intended recipient;
• determining whether the message transfer agent is in the realm of the intended recipient;
• if the message transfer agent is determined to be in the realm of the intended recipient, then storing the communication in a message store server associated with the message transfer agent;
• and
• if the message transfer agent is determined not to be in the realm of the intended recipient, then
• identifying a message transfer agent in the realm of the intended recipient within said network domain, by performing a DNS lookup, and
• relaying the communication within said network domain to the message transfer agent in the realm of the intended recipient, without altering the recipient address.

A message transfer agent to operate in a network domain on a network, the message transfer agent comprising:

• a mail router to determine whether the message transfer agent is responsible for delivering an email communication received over a network to a mail store of an intended recipient of the email communication, the email communication having a recipient address indicating the intended recipient;
• a mail store deliverer to store the email communication in a mail store server associated with the message transfer agent if the message transfer agent is responsible for delivering the email communication to the mail store of the intended recipient;
• and
• a relay deliverer to relay the communication to another message transfer agent within said network domain, without altering the recipient address of the communication, if the message transfer agent is not responsible for delivering the email communication to the mail store of the intended recipient.

A machine-readable program storage medium storing a set of instructions, the instructions for use in a processing system operable as a message transfer agent on a network, to configure the processing system to execute a process comprising:

• receiving, at the message transfer agent, an email communication transmitted over the network, the email communication having a recipient address indicating an intended recipient of the email communication;
• identifying a realm of the intended recipient from a plurality of realms defined within a single network domain;
• determining whether the message transfer agent is in the realm of the intended recipient;
• if the message transfer agent is in the realm of the intended recipient, then storing the communication in a message store server associated with the message transfer agent;
• and
• if the message transfer agent is not in the realm of the intended recipient, then
• identifying a message transfer agent in the realm of the intended recipient within said network domain, and
• relaying the communication within said network domain to the message transfer agent in the realm of the intended recipient, without altering the recipient address of the communication.

A processing system comprising:

• a processor;
• a data communication device to couple the processing system to a network;
• and
• a storage device storing instructions for execution by the processor, to configure the processing system to operate as a message transfer agent in a network domain, the instructions configuring the processing system to execute a process comprising
• receiving, at the message transfer agent, an email communication transmitted over the network, the email communication having a recipient address indicating an intended recipient of the email communication, wherein said recipient address is contained in an envelope of the communication, the communication further having a header,
• determining whether the message transfer agent is responsible for delivering the email communication to a mail store of the intended recipient, and
• if the message transfer agent is not responsible for delivering the email communication to a mail store of the intended recipient, then relaying the communication to another message transfer agent within said network domain, without rewriting the recipient address of the communication.

A message transfer agent in a network domain on a network, the message transfer agent comprising:

• means for receiving an email communication at the message transfer agent, the email communication having a recipient address indicating an intended recipient of the email communication;
• means for determining whether the message transfer agent is responsible for delivering the email communication to a mail store of the intended recipient;
• and
• means for relaying the communication to another message transfer agent within said network domain, without altering the recipient address of the communication if the message transfer agent is not responsible for delivering the email communication to the mail store of the intended recipient.