Environment variables for network connections
The INFORMIXCONTIME (connect time) and INFORMIXCONRETRY (connect retry) environment variables affect the behavior of the client when it is trying to connect to a database server. Use these environment variables to minimize connection errors caused by busy network traffic.
If the client application explicitly attaches to shared-memory segments, you might be required to set INFORMIXSHMBASE (shared-memory base).
You can use the INFORMIXSERVER environment variable to specify a default dbserver name to which your clients connect.