diff --git a/defaults/main.yml b/defaults/main.yml
index 2e2c306..e579a7a 100644
--- a/defaults/main.yml
+++ b/defaults/main.yml
@@ -22,6 +22,8 @@ mailserver:
       drop_user_agent:
         regex: '^User-Agent:'
         action: IGNORE
+  postsrsd:
+    srs_domain: "srs.{{ inventory_hostname }}"
   dovecot:
     debug: false
   postfixadmin:
diff --git a/templates/postsrsd/default.j2 b/templates/postsrsd/default.j2
index 19b81e2..d10a387 100644
--- a/templates/postsrsd/default.j2
+++ b/templates/postsrsd/default.j2
@@ -4,7 +4,7 @@
 # Addresses are rewritten to originate from this domain. The default value
 # is taken from `postconf -h mydomain` and probably okay.
 #
-#SRS_DOMAIN=
+SRS_DOMAIN={{ mailserver.postsrsd.srs_domain }}
 
 # Exclude additional domains.
 # You may list domains which shall not be subjected to address rewriting.