We present symmetric collocation methods for linear differential-algebraic
boundary value problems without restrictions on the index or the structure
of the differential-algebraic equation. In particular, we do not require
a separation into differential and algebraic solution components.
Instead, we use the splitting into differential and algebraic equations
(which arises naturally by index reduction techniques) and apply
Gauss-type (for the differential part) and Lobatto-type (for the
algebraic part) collocation schemes to obtain a symmetric method 
which guarantees consistent approximations at the mesh points.
Under standard assumptions, we show solvability and stability
of the discrete problem and determine its order of convergence.
Moreover, we show superconvergence when using the combination of
Gauss and Lobatto schemes and discuss the application of interpolation
to reduce the number of function evaluations.
Finally, we present some numerical comparisons to show the reliability
and efficiency of the new methods.