How to specify the local ip address to connect from

Hello,

I'm using FreeTDS to connect to a MS SQL Server. This worked fine on the 
development host, because only the one single IP address of it had to be 
whitelisted in the firewall of the MS SQL Server.

But on the production server, several aliased network interfaces with 
different IP addresses are set up and the web application is obviously 
not connecting through the main interface, which is already whitelisted.

How can I set the local ip address / interface that FreeTDS connects 
from to the remote database host?

Kind regards
Marten Lehmann