How to use windows authentication to connect to MS SQL server from windows workstation in another domain with Python

Question

I'm trying to connect to SQL server 2000 installed on Windows server 2003 from Windows Server 2008 R2 using Python 3.4 and pyodbc module. Those servers are in different AD domains. Windows only authentication is enabled on SQL server and I can't change that.

drv = '{SQL server}'
svr = 'sql.my-domain.local'
usr = 'my-domain.local\testuser'
pwd = 'password'
db = 'testdb'
pyodbc.connect(driver=drv, server=svr, user=usr, password=pwd, database=db)

The connection above fails with the following error:

pyodbc.Error: ('28000', "[28000] [Microsoft][ODBC SQL Server Driver][SQLServer] 
Login failed for user 'svx-iroot.local\\sqlexecutive'. 
Reason: Not associated with a trusted SQL Server connection. (18452) (SQLDriverConnect)")

There are some questions, for example this one, suggesting to add trusted_connection='yes' argument to pyodbc connection for support of windows authentication but in this case it does not help because with this option local credentials are used and I need to provide credentials explicitly because originating workstation is in a different AD domain.

Creation of User DSN in ODBC Data Source Administrator with SQL Server driver fails with the same error mentioned above.

Is there a way to make this work?

Meanwhile I installed FreeTDSdriver for Windows from http://sourceforge.net/projects/freetdswindows/ and connection test using tsql utility does work:

tsql -S sql.my-domain.local -U my-domain.local\testuser -P password

But FreeTDSdriver is not available in ODBC Data Source Administrator. FreeTDS driver is traditionally used with unixODBC. Is it possible to use this driver in Windows environment with pyodbc?

Update:

It turns out FreeTDS binaries mentioned above include unixODBC as well. Configuration of freetds.conf, odbc.ini and odbcinst.ini was made like described, for example, here. But at this point I don't have understanding how pyodbc is supposed to know that FreeTDS driver exists. And indeed connection attempt with FreeTDS driver fails with the following error:

pyodbc.Error: ('IM002', '[IM002] [Microsoft][ODBC Driver Manager] 
Data source name not found and no default driver specified (0) (SQLDriverConnect)')

Pyodbc only knows about drivers available in ODBC Data Source Administrator:

There are 2 ways to move forward. First option is to make ODBC Data Source Administrator aware of FreeTDS driver. To achieve that a new value needs to be created in registry key HKEY_LOCAL_MACHINE\SOFTWARE\ODBC\ODBCINST.INI\ODBC Drivers with name FreeTDS and value Installed. Then a new key FreeTDS is created in HKEY_LOCAL_MACHINE\SOFTWARE\ODBC\ODBCINST.INI and settings for FreeTDS driver are set as string values in this registry key.

After completion of this procedure FreeTDS driver became available in ODBC Data Source Administrator but connection still failed. Attempt to create User DSN in ODBC Data Source Administrator with FreeTDS fails with error code 193 which is caused by incompatibility of 64 bit ODBC Data Source Administrator and 32 bit version FreeTDS. I don't have 64 bit version of FreeTDS available. Potentially it could be possible to compile it from source.

Another option is to make pyodbc use another driver manager (unixODBC) instead of ODBC Data Source Administrator. Don't know how to approach that yet.

Answer 1

I ended up using pymssql version 2.1.3 installed with a wheel obtained from http://www.lfd.uci.edu/~gohlke/pythonlibs/#pymssql. It has FreeTDS included and it worked right out of the box:

import pymssql
conn = pymssql.connect(
  host=r'sql.my-domain.local',
  user=r'my-domain.local\testuser',
  password='password',
  database='testdb'
)
cursor = conn.cursor()
cursor.execute('SELECT * FROM testtable')