Network administrators are fuming about changes made by domain registrar Verisign to the DNS system yesterday amid concern that the alterations could make it difficult for mail servers to reject mail from invalid domains.

Verisign yesterday added wildcard DNS records to all .com and .net domains - redirecting surfers who get lost on the Net to a search page, called Site Finder, run by the company. Those who type in non-existent addresses will also be served up Site Finder, instead of an error message.

The radical, and largely unheralded, changes were made yesterday and followed up by a post by Verisign to the NANOG mailing list. This did little beyond stating that Verisign has added a "wildcard A record to the .com and .net zones" and pointing users to a white paper that Verisign has prepared .

So, Verisign has turned domain name typos into an advertising opportunity. This is an abuse of Verisign's role, via acquired company Network Solutions, in running the root DNS servers.

And then there are the practical issues: sysadmins are fuming at the knock-on effects of the changes.

The concerns raised by Reg reader Ray Bellis, technical director of rural broadband outfit Community Internet, are typical.

"This breaks all sorts of things horribly. It makes it very difficult for mail servers to reject mail from invalid domains", Bellis said..

"Even worse, if an MX record points to an invalid host name, that host will now resolve, the SMTP connection accepted and the mail then rejected. Because the rejection is a 550 error, that mail will not get retried *ever* again. If that MX was the highest priority mail server than all mail to that domain name will bounce."

Already a backlash is building, with Net admins being urged to block Verisign's catch-all domain. This could get very messy. ®