diff --git a/roles/postfix/vars/main.yml b/roles/postfix/vars/main.yml
index 34eca6d24..7e7330df4 100644
--- a/roles/postfix/vars/main.yml
+++ b/roles/postfix/vars/main.yml
@@ -12,6 +12,9 @@ postfix_relay_hosts_addresses:
   - catalog3.princeton.edu
   - catalog4.princeton.edu
   - catalog5.princeton.edu
+  - catalog-indexer1.princeton.edu
+  - catalog-indexer2.princeton.edu
+  - catalog-indexer3.princeton.edu
   - cdh-derrida1.princeton.edu
   - cdh-derrida2.princeton.edu
   - cdh-derrida-crawl1.princeton.edu