The group that oversees the Internet's address system has released a toolkit for Web site designers and application developers to fix problems caused by recently added Internet addresses.

Some Web sites and applications are rejecting addresses ending in newer Top-Level Domains such as ".mobi" or ".info," causing inconvenience for users, the Internet Corporation for Assigned Names and Numbers (ICANN) said on Friday.

Many TLDs have been added in recent years to supplement ".com" and ".net," but some applications have not been updated to accommodate the changes, ICANN said. The work can be time-consuming for developers, it added.

ICANN's toolkit includes a piece of code that fixes the problem by allowing applications to check the validity of an e-mail address or Web site against the "root-zone," a master list where Web sites with certain TLDs can be looked up. That look-up translates the URL of a Web site from words into a numerical address that allows the page to be called up by a browser.

The code, which is available for download from ICANN's Web site, is available in C#, Java, Perl, and Python under an open source license.

The code is easy to insert into existing programs, according to ICANN, and will be updated automatically to check the validity of an email address or a URL. It needs to be installed only once and will update the application when TLDs are added or changed.

There are already more than 240 country-code TLDs, such as .fr for France, and other TLDs will appear soon, such as ".asia."

This is the third beta release of the code, which was created by Kim Davis, a technical liaison to the Internet Assigned Numbers Authority (IANA), an ICANN group.

"The real benefit is going to come when more people start to use this," said Andrew Robertson, an ICANN spokesman.