Most PCI and many older ISA network cards are supported. Some network interface cards are not supported by most Debian installation disks, such as AX.25 cards and protocols; NI16510 EtherBlaster cards; Schneider & Koch G16 cards; and the Zenith Z-Note built-in network card. Microchannel (MCA) network cards are not supported by the standard installation system, but see Linux on MCA for some (old) instructions. FDDI networks are also not supported by the installation disks, both cards and protocols.

As for ISDN, the D-channel protocol for the (old) German 1TR6 is not supported; Spellcaster BRI ISDN boards are also not supported by the debian-installer.