Cygwin Chmod

I tried to use the following command:

chmod 600 .netrc

but the file permissions did not change (-rw-r--r--)

OS is NT2000.

I checked all the file settings, etc.  to make sure i had read/write/modify
permission.  I could remove/add write permissions (e.g. -r--r--r--), but
could not eliminate the read permissions for groups and others.

Is this a bug, or am I missing something?

Thanks

Tom