Set default propagation time to 900s (15min)

Resolves #28

README.rst

@@ -61,12 +61,12 @@ Usage
 -----
 
 To acquire a single certificate for both ``example.com`` and
-``*.example.com``, waiting 900 seconds for DNS propagation::
+``*.example.com``, waiting 1200 seconds (20min) for DNS propagation::
 
     certbot certonly \\
       --authenticator dns-netcup \\
       --dns-netcup-credentials ~/.secrets/certbot/netcup.ini \\
-      --dns-netcup-propagation-seconds 900 \\
+      --dns-netcup-propagation-seconds 1200 \\
       --keep-until-expiring --non-interactive --expand \
       --server https://acme-v02.api.letsencrypt.org/directory \
       -d 'example.com' \\
@@ -90,12 +90,16 @@ certbot's command line:
 
 ``--dns-netcup-propagation-seconds NUM`` | waiting time for DNS to propagate before asking
                                          | the ACME server to verify the DNS record.
-                                         | (Default: 10, Recommended: >= 600)
+                                         | (Default: 900, Recommended: >= 600)
 ======================================== =======================
 
+**NOTE:**
 You may need to set an unexpectedly high propagation time (≥ 900 seconds) to
 give the netcup DNS time to propagate the entries! This may be annoying when
 calling certbot manually but should not be a problem in automated setups.
+In exceptional cases, 20 minutes may be required. See `#28`_.
+
+.. _#28: https://github.com/coldfix/certbot-dns-netcup/issues/28
 
 
 Credentials

certbot_dns_netcup.py

@@ -46,7 +46,8 @@ def __init__(self, *args, **kwargs):
 
     @classmethod
     def add_parser_arguments(cls, add):
-        super(Authenticator, cls).add_parser_arguments(add)
+        super(Authenticator, cls).add_parser_arguments(
+            add, default_propagation_seconds=900)
         add('credentials', help='netcup credentials INI file.')
 
     def more_info(self):