Trackback URL Tag
In order to display the trackback URL for an entry, so that people can send you Trackbacks, you must use the trackback URL tag:
{exp:trackback:url}
This is a single variable, so there is no pair of tags. Note that this is the URL that other people will use to submit a trackback for your entry. It is not the URL to the page you will use to display trackbacks for an entry.
User Contributed Notes
You must have an ExpressionEngine license and have attained a forum rank of "Lab Assistant" (100 posts) to contribute notes to the User Guide