Dielectric spectroscopy has often been used to study confinement effects in alkylcyanobiphenylliquid crystals. In this paper, we highlight some of the effects that have been discoveredpreviously and add new data and interpretation. Aerosil nanoparticles form a hydrogenbonded random porous network. In dispersions of alkylcyanobiphenyls with aerosils, anadditional slow process arises, that we ascribe to the relaxation of liquid crystal moleculesin close interaction with these nanoparticles. Their relaxation is retarded by a hydrogenbond interaction between the cyano group of the liquid crystals and an aerosil surfacehydroxyl group. A similar surface process is also observed in Vycor porous glass,a random rigid structure with small pores. A comparison of the temperaturedependence of the relaxation times of the surface processes in decylcyanobiphenyland isopentylcyanobiphenyl is made, both for Vycor and aerosil confinement. Indecylcyanobiphenyl, the temperature dependence for the bulk and surface processes isArrhenius (in a limited temperature range above the melting point), except in Vycor,where it is a Vogel–Fulcher–Tamman dependence (over a much broader temperaturerange). In bulk and confined isopentylcyanobiphenyl, the molecular processes have aVogel–Fulcher–Tamman dependence, whereas the surface processes have an Arrhenius one.Another effect is the acceleration of the rotation around the short molecular axis inconfinement, and particularly in aerosil dispersions. This is a consequence of the disorderintroduced in the liquid crystalline phase. The disorder drives the relaxation timetowards a more isotropic value, resulting in an acceleration for the short axisrotation.