When running Get-ReceiveConnector, the contents of the RemoteIPRanges field may be truncated if there are a lot of entries. You can "expand" the list:

Get-ReceiveConnector MyConnector | Select -expand RemoteIPRanges | FT

This will expand each of the IP range objects and FT makes sure it's nicely formatted in a table. For single addresses, you only need the LowerBound column, but if ranges have been specified, you probably want both columns.