Microsoft is proposing to stop spam by checking that messages are being sent by the person they claim to come from.
Gates: Wants changes to net mail system
The Caller-ID for e-mail idea is one of several proposals floated as a way to stem the rising tide of junk mail.
The internet's engineering body has set up an emergency meeting to sift through the different proposals and draw up a network-wide solution.
But some fear the competing proposals could cause confusion and spell the end of some widely-used net features.
Spammers hide their location by using a false, or spoofed, address in the millions of messages they send out.
They can get away with this because mail servers only check if a domain mentioned in these spoofed addresses is known to be used by spammers.
"Having e-mail come in, and not really being able to identify where it comes from, this is a huge security hole," said Bill Gates, Microsoft chairman, during a keynote speech at the RSA Security Conference where he unveiled the idea.
Microsoft is proposing changes to the net's mail handling systems that will make organisations register the net addresses of their mail servers.
When a message arrives, its domain will be checked to ensure that it originated where it said it did. If not it will be deleted.
Microsoft said its Hotmail subsidiary will start registering its mail servers soon and it has been joined by Amazon and spam filtering firm Brightmail.
But many other companies are committing to the Sender Policy Framework, (SPF), which works in a similar fashion to Microsoft's Caller-ID idea.
"Spam is the cholesterol of the internet," said Steve Raber, head of mail filtering firm Ciphertrust, "it is just clogging up everything."
SPF also involves checking e-mail to ensure that the address it uses is related to the net address it comes from.
Viagra, herbal remedies and other drugs feature in spam
Almost 8,000 organisations have registered with the SPF co-ordinating body.
Net portal Yahoo has proposed a different system called DomainKeys that uses encryption to prove a message's origins.
The competing proposals have sparked worries at the Internet Engineering Task Force which oversees the technical development of the net.
The IETF has convened a meeting that will sift through the proposals and try to work out a specification that the whole net can use.
Without such intervention many fear that these spam-stopping systems could disrupt some well-known features of online life.
Mail-forwarding systems that let people route e-mail through servers other than those run by their net service provider could suffer.
News sites could be hit as the proposals could stop them letting readers e-mail stories to friends by clicking on a button.