The deal will give Symantec many new customers

The companies have said they would offer Symantec's Norton Internet Security to Yahoo customers at discounted rate, Reuters reported.

The deal will help Yahoo compete against internet rivals Google and Microsoft and give Symantec access to millions of potential customers.

Symantec already provides anti-virus scanning for Yahoo email users.

Yahoo users in the US can sign up for Norton security software for a reduced annual subscription of $49.99 (�27), a discount of $20 (�11) on the usual price, after a 30-day free trial.

Yahoo plans to promote the initiative through its network, which includes Yahoo Mail, the Yahoo toolbar and Yahoo search.

In addition, Symantec will provide spyware software for the Yahoo toolbar, and anti-virus and firewall protection for Yahoo broadband users.