  We obtain exact expressions for the two-time autocorrelation and response
functions of the $d$-dimensional linear Glauber model. Although this linear
model does not obey detailed balance in dimensions $d\geq 2$, we show that the
usual form of the fluctuation-dissipation ratio still holds in the stationary
regime. In the transient regime, we show the occurence of aging, with a special
limit of the fluctuation-dissipation ratio, $X_{\infty}=1/2$, for a quench at
the critical point.
