TCP/IP channel option files control various characteristics of TCP/IP channels. Channel option files must be stored in the MTA configuration directory and named x_option, where x is the name of the channel. For example, /msg_svr_base/config/tcp_local_option
The option file consists of one or more keywords and associated values. For example you can disable mailing list expansion on your server by including the DISABLE_EXPAND keyword in the option file and setting the value to 1.
Other option file keywords allow you to:
Set a limit on the number of recipients allowed per message (ALLOW_RECIPIENTS_PER_TRANSACTION)
Set a limit on the number of messages allowed per connection (ALLOW_TRANSACTIONS_PER_SESSION)
Fine tune the type of information logged to the MTA log file (LOG_CONNECTION, LOG_TRANPORTINFO)
Specify the maximum number of simultaneous outbound connections that the client channel program allows (MAX_CLIENT_THREADS)
For information about all channel option keywords and syntax, see the Sun Java System Messaging Server 6 2005Q4 Administration Reference.