When a client running in an application server wishes to connect to the bus to do some messaging work it looks up a connection factory in JNDI and uses it to create a connection. In order to create a connection the connection factory queries the Work Load Manager (WLM) service to find out where a messaging engine is running and connects to it. Configuring the connection factory simply requires the bus name to be specified.
When a client running remotely from the cell, for instance in the client container, or a thin client, connects it does something similar. It obtains a connection factory (usually via a JNDI lookup to an application server) and creates a connection. In this situation though the connection factory has no WLM service to use to locate a suitable messaging engine. In this situation the connection factory connects to an application server and that application server performs the WLM query. This application server is termed a bootstrap server.
In v6.x a bootstrap server is designated simply by configuring the SIB service to be on, so all servers that are members of any bus are automatically bootstrap servers. Additionally in v7 you can also choose to designate servers as bootstrap member.
The servers to connect to to run the query are configured in the connection factory using a property called the provider endpoints. Working out which servers and ports can be used to bootstrap can be a bit of a chore in v6.x. Several panels need to be navigated around to work out the host and ports that are available. In v7 we have introduced a new feature to make this much simpler. This is the bootstrap members collection.
This collection can be found on the main bus panel and is titled "Bootstrap Members" (below the Bus Members link). Clicking on it shows the following collection:
This lists each server that can be used as a provider endpoint, including the ports that are available on that panel. There is one proviso though. It lists all the ports associated with messaging includes ones that may not be enabled. In the example shown above the ports 7278, 7279 and 7276 are shown, but the bus has been configured to allow only SSL protected transports, so the unsecured ports will not be open.