Index: src/wp-admin/includes/class-wp-comments-list-table.php
===================================================================
--- src/wp-admin/includes/class-wp-comments-list-table.php	(revision 29770)
+++ src/wp-admin/includes/class-wp-comments-list-table.php	(working copy)
@@ -525,14 +525,14 @@
 				comment_author_email_link();
 				echo '<br />';
 			}
-			echo '<a href="edit-comments.php?s=';
-			comment_author_IP();
-			echo '&amp;mode=detail';
-			if ( 'spam' == $comment_status )
-				echo '&amp;comment_status=spam';
-			echo '">';
-			comment_author_IP();
-			echo '</a>';
+			$comment_author_IP = get_comment_author_IP();
+			if ( ! empty( $comment_author_IP ) ) {
+				echo '<a href="edit-comments.php?s=' . $comment_author_IP . '&amp;mode=detail';
+				if ( 'spam' == $comment_status ) {
+					echo '&amp;comment_status=spam';
+				}
+				echo '">' . $comment_author_IP . '</a>';
+			}
 		}
 	}