Here is what I would recommend...
1) Add another sub that is a confirmation screen that users have to check before making the final submission. Look at the
Add Confirmation Mod for
Links 2.0 in the
Resource Center. You can port the codes in the
Links SQL version of add.cgi.
2) Read the posts I wrote in the
Perl/CGI Forum about this very issue...I have provided codes for
Links 2.0 that can easily be applied to
Links SQL. Basically, it will disallow re-loading of the success of page to add the link again. And the user is presented with an error message stating that they have already added the link.
3) Use widgetz's
modify.cgi Mod that also include codes for the
add.cgi tnat will make users login first before adding links. This Mod can be found in this forum. Search for
widgetz forum.cgi.
4) Add
IP Address Blocking codes (that can be found at
http://lookhard.hypermart.net/links-mods/ and can be ported to
Links SQL - look for
Block URL Mod) to your
add.cgi that will check a list of blacklisted IP addresses and will prevent users with that IP address from adding links to your site.
5) Wait until the next version of
Links SQL and see if there are more secure and robust user login features.
Regards,
Eliot Lee