Hi everyone
I'm having trouble configuring the SDK client on Ubuntu. My client is running version 14.10.FC11WE and I have the client: Informix.4.50.FC11
I've already configured /etc/odbcinst.ini as: [Informix]
Description=IBM Informix ODBC Driver
Driver=/opt/IBM/Informix.4.50.FC11/lib/cli/iclit09b.so and in /etc/odbc.ini [caja]
Description=ODBC Connection to Informix
Driver=Informix
Database=db
Servername=sn_caja_aux
Host=ip
Service=2325
Protocol=onsoctcp
UID=user
PWD=password,sql host: sn_caja_aux onsoctcp ip 2325 but when I connect I get the error: ERROR [IM002] [unixODBC][Driver Manager]Data source name not found and no default driver specified

Two things stand out to me:

1. Your /etc/odbcinst.ini needs this line:

IBM Informix ODBC DRIVER=Installed

2. You need to specify the driver in /etc/odbc.ini:

Change "Driver=Informix" to 

Driver=/full/path/to/iclit09b.so

See my working example below.

In the system-wide ODBC drivers config file /etc/odbcinst.ini:

;-----------------------------------------------------------------------
; Section 1:  List of ODBC drivers installed on the system
[ODBC Drivers]
IBM Informix ODBC DRIVER=Installed
;-----------------------------------------------------------------------
; Section 2:  List of properties for specific ODBC driver(s). 
[IBM Informix ODBC DRIVER]
Description=IBM Informix ODBC Driver
Driver=/opt/informix/lib/cli/iclit09b.so
Setup=/opt/informix/lib/cli/iclit09b.so
APILevel=1
ConnectFunctions=YYY
DriverODBCVer=03.51
FileUsage=0
SQLLevel=1
smProcessPerConnect=Y
;-----------------------------------------------------------------------
; Section 3:  ODBC global options such as Unicode or Tracing
[ODBC]
Trace = no
TraceFile = /tmp/odbctrace.log

I put my individual connection setups in ~/.odbc.ini but these should
work for system-wide use in /etc/odbc.ini:

[stores_demo]
Description=IBM Informix 12.10 stores_demo database via ODBC
Driver=/opt/informix/lib/cli/iclit09b.so
Database=stores_demo
; Informix uses OS authentication, so does not need LogonID or pwd,
; if the client is on the same system as the database server.
; Might need this if connecting remotely (UNTESTED).
;LogonID=odbc
;pwd=odbc
Servername=ids12de
CursorBehavior=0
CLIENT_LOCALE=en_us.8859-1
DB_LOCALE=en_us.8859-1
TRANSLATIONDLL=/opt/informix/lib/esql/igo4a304.so

Notes:
* Make /opt/informix a symlinks to your installed version of Informix
  (e.g., /opt/ibm/informix/ids12.10.FC16W1DE) so you don't have to 
  update the ODBC configuration files if/when Informix is upgraded.
* I'm only using a local connection, not over TCP/IP, but your Host,
  Service, Protocol, UID look OK.
* Set Trace=yes in /etc/odbcinst.ini (Section 3) to help debug.
  The log file is whatever you set TraceFile to, /tmp/odbctrace.log
  in my example.

scot

I found Lester Knutsen's video helpful:

Connecting Users and Tools to Informix Servers - skip to 36 minutes in 
the video[1] or look at the slides[2] for how to set up a unixODBC 
connection to Informix.

[1] https://advancedatatools.com/webcasts/informix-tutorial-connecting-users-and-tools-to-informix-servers/
[2] https://advancedatatools.com/wp-content/uploads/2020/06/Informix_Tutorials-Connecting_to_Informix.pdf