use symbolic service in postfix

howto/submission.md

@@ -198,7 +198,7 @@ following commands:
     postconf -e smtp_sasl_auth_enable=yes
     postconf -e smtp_sasl_password_maps=hash:/etc/postfix/sasl/passwd
     postconf -e smtp_sasl_security_options=
-    postconf -e relayhost=submission.torproject.org:587
+    postconf -e relayhost=submission.torproject.org:submission
     postconf -e smtp_tls_security_level=encrypt
     postfix reload