How to Set up DNS for iCal Service on Lion Server - dummies

How to Set up DNS for iCal Service on Lion Server

By John Rizzo

DNS isn’t required for Lion’s iCal Server, but DNS can make it work better. Clients use DNS to keep track of iCal Servers, a self-discovery feature. To enable this feature, you can create a Service (SRV) record in each DNS zone that has the CalDAV calendar service. The SRV record needs to be in a special format as well.

Adding a DNS SRV record for iCal Server in Lion Server

If you’re using Lion Server for your DNS service, you can use Server Admin to add an SRV record for iCal Server. You add it to the DNS zone that your server is in. If you had Open Directory created during setup, the Setup Assistant will have created Primary and Reverse Zones; in this case, you’d create the SRV record in the Primary Zone.

Here’s how to create the SRV record for iCal Server:

  1. In Server Admin, click the triangle to the left of your server name in the left column to expand the list of services.

  2. Click DNS in the list of services.

  3. Click the Zones icon in the toolbar.

  4. Click to select the zone that the server is located in.

    This may be the Primary Zone, as indicated in the Type column.

  5. Click the Add Record button and select Add Service (SRV) from the pop-up menu.

    A new SRV record is created.

  6. Type the following in the fields in the bottom half of the window:

    • Service Name: Leave this field blank.

    • Service Type: If you aren’t using SSL for iCal, type _caldav._tcp. If you’re using SSL, type _caldavs._tcp.

      Be sure to include the underscores.

    • Host: Type your server’s DNS name (include a period at the end).

    • Port: If you aren’t using SSL for iCal, enter 8008. Type 8443 if you’re using SSL.

    • Priority and Weight: Type 0 in each field.

    • TXT: Leave this field blank.

  7. Click the Save button.


DNS SRV record format for iCal Server

On any DNS server, the SRV record needs to be in this format (on one line): 86400 IN SRV 0 0 8008

The _caldav._ term is for a standard connection. If you’re using a secure SSL connection, use _caldavs._ instead.

The standard port number is 8008. For SSL connections, use port 8443.

The 0 0 after SRV represent the priority and weight. These are 0 if only one CalDAV server is on the network. If multiple CalDAV servers are on the network, use numbers other than 0.

The 86400 represents the DNS time-to-live number, in seconds. 86400 is one day, but you can use another time period.