The official OpenNIC mailing lists are served by sympa. See below for descriptions of available lists and instructions for subscribing.
OpenNIC Discuss
This low-volume list is for folks discussing the organization and operation of the OpenNIC project. All are welcome to subscribe. Subscribe by sending an email to discuss-subscribe@lists.opennicproject.org with 'subscribe' in the body of the message.
Archives of this list can be found on Gmane or here.
OpenNIC DNS Operations
This low-volume list is to discuss infrastructure details, DNS installation, maintenance, and best practices, and other issues related to administering a Tier1 or Tier2 name server. All are welcome to subscribe on a read-only basis; only active T1/T2 administrators will be permitted posting access. Subscribe by sending an email to dns-operations-subscribe@lists.opennicproject.org with 'subscribe' in the body of the message or visit this site. However, the subscription requires approval and will be approved in a reasonable amount of time. By subscribing to this list you will ALSO be AUTOMATICALLY subscribed to the DNS reports list.
OpenNIC DNS Reports
This list is used for DNS reports that include T1/T2 reports as well as certain outage notifications. ALL members of dns-operations will be automatically subscribed to this list.