April 25, 2019

Net Gains: Networking Adapters - page 2

Your Physical Connection to the Network

  • May 23, 2000
  • By William Wong

A networked Linux PC will normally have a single network adapter which allows the PC to communicate with other PCs on the network. Linux supports file and printer sharing, to be covered in Part 3: File Sharing With Samba as well as Part 7: File Sharing With NFS and Part 8: File Sharing With Netware.


A Linux PC acting as a router or firewall will have a second network adapter. This configuration, shown in Figure 2, will be covered in Part 4: Linking A Network To The Internet. We take a closer look at the addition of a second network adapter in this article. A Linux PC acting as a gateway to the Internet using a modem has a similar configuration and this will be covered in Part 5: Dial-up Connections.

Ethernet network adapters can be found the motherboard or plugged into a PCI or ISA slot. Laptop PCs will use PCMCIA or PC Card adapters instead of PCI or ISA adapters. These require PCMCIA drivers in addition to the network drivers. PCMCIA support is included with most Linux distributions and must be installed prior to using a PC Card adapter. If this support is not installed then see about getting the latest version of Linux.

External adapters may plug into USB or parallel-port connectors. USB adapters will require USB support in addition to the Ethernet drivers, although I have yet to find any Linux USB drivers for Ethernet devices.

Motherboard-based or PCI adapters are preferable. These have the widest support and are the easiest to configure. They also tend to support Plug-and-Play (PNP) operation, greatly simplifingsoftware installation. To use a PCI adapter, just plug it into the PC and move onto driver installation. The same will be true for PNP ISA adapters.

If you have a non-PNP ISA network adapter then check out the documentation to determine what jumper settings may be required. Minimally an IO port must be set. A DMA and interrupt may also need to be set. Record this information for driver installation.

I/O port, interrupt, and DMA resources used by a network adapter must not conflict with other adapters. The resources in use can be found by viewing the text files /proc/interrupts, /proc/dma, and /proc/ioports. The file /proc/pci lists all installed PCI adapters. This information is obtained using the PNP support.


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