diff --git a/nlsr.conf b/nlsr.conf
index a370f34..d32a463 100644
--- a/nlsr.conf
+++ b/nlsr.conf
@@ -187,7 +187,8 @@
             k-regex ^([^<KEY><NLSR>]*)<NLSR><KEY><ksk-.*><ID-CERT>$
             k-expand \\1
             h-relation equal
-            p-regex ^([^<NLSR><LSA>]*)<NLSR><LSA>(<>*)<><><>$
+            ; the last four components in the prefix should be <lsaType><seqNo><version><segmentNo>
+            p-regex ^([^<NLSR><LSA>]*)<NLSR><LSA>(<>*)<><><><>$
             p-expand \\1\\2
           }
         }