I have multisite 1.2.68 and joomla 1.7.1

I have a master website located at (main-domain).com
And I have slave websites at slave1.(main-domain).com, slave2.(main-domain).com, etc.

Currently, robots.txt at master website is showing up on all slave websites.

How do I separate robots.txt so each slave site will have its own customized robots.txt file?

Sorry if this is written somewhere. I did research first.

Thank you very much

You just have to specify in the JMS Template rule that you defined to build the slave site that you want a "copy" for the "robots.txt" file instead of a Symbolic Link.

So go in the JMS Template menu and edition the rule that you created.
In the template, select "folder and files" tabs where you have the list of all the files and folders for which you can defined the action.

See also the tutorial video 0.b slide 30 to 34 that explain some values in the template rules.
www.jms2win.com/en/tutorial#jms12x-0b