Index: wp-admin/edit-form-comment.php
===================================================================
--- wp-admin/edit-form-comment.php	(revision 25309)
+++ wp-admin/edit-form-comment.php	(working copy)
@@ -91,6 +91,12 @@
 <label class="spam"><input type="radio"<?php checked( $comment->comment_approved, 'spam' ); ?> name="comment_status" value="spam" /><?php /* translators: comment type radio button */ _ex('Spam', 'adjective'); ?></label>
 </div>
 
+<?php $whois_link = sprintf( 'http://whois.arin.net/rest/ip/%s', $comment->comment_author_IP ); ?>
+
+<div class="misc-pub-section">
+	<?php _e('IP address:'); ?> <a href="<?php echo esc_url($whois_link); ?>"><?php echo esc_html($comment->comment_author_IP); ?></a>
+</div>
+
 <div class="misc-pub-section curtime misc-pub-curtime">
 <?php
 // translators: Publish box date format, see http://php.net/date