Using a node in the cluster to dial out from other nodes
This configuration requires a more than average knowledge of Asterisk dialplan and SIP configuration. In general, you cannot use one node as "Provider" for other nodes. Calls between nodes are managed as "internal" calls and the call will fail. However, there can be the need to send out special calls from one node only. Let's make the example of a node in the cluster hosting a Dahdi interface. To allow all other nodes to use the Dahdi interface to dial out special numbers, a special configuration needs to be done.
First you need to remove from sip.conf the parameter "insecure=port,invite" from all the host accounts. This parameter authenticate nodes using IP Address and it is used as a fallback when for some reason the user/password authentication doesn't work, for example due to a server name change not applied to sip.conf.
Then you need to create a new account, in sip.conf for the communications between the other servers in the cluster and the node hosting the Dahdi interface
On the Provider page, add the provider for this account
As you have seen, the new account/provider is mapped to the context [dahdi]. Create that context and dial the Dahdi interface: