The Pi Zero has the limitation of only having a single USB port. If you want to put your Pi Zero on the LAN, then you need to add a network port, this is normally done using a USB Nic.

I hate buying anything for the Pi Zero that costs proportionally more than the Pi Zero, and USB network adapters fall in to that category. Pay a few quid for one, and you only get a crappy unreliable Nic that is sold as USB2, but is normally an old USB 1.x and that fails all the time, believe me, I have tried a lot of them.

Then I came across this website http://raspi.tv/2015/ethernet-on-pi-zero-how-to-put-an-ethernet-port-on-your-pi

What they have done is used a network module that runs on the SPI bus. Its a cheap unit that you can get from ebay for around £3, and while they are cheap, they are reliable, albeit a little slow, but not so slow that they are unusable. I will take reliability over speed any day.

Here is the unit I purchased from eBay for £2.07p

The seller on eBay is chips-fans and while it has the same part number as the one used on raspi.tv, the pins are different, which is a bit annoying, but it wasn't to hard to work out.

Here are the connections I used for this board:

  GPIO     RPi Pin    Nic PNo    Nic Func
  
  n/c                 1          CLK
  n/c                 2          WOL
  GPIO10   19         3          SI
  GPIO08   24         4          CS
  3v3      17         5          Vcc
  GPIO25   22         6          NT
  GPIO09   21         7          SO
  GPIO11   23         8          SCK
  n/c                 9          RST
  GND      20         10         GND

Enable the SPI Pins:

  From the command line
  
  sudo raspi-config
  
  Advanced Options - SPI - Yes to Enable

Add the following to your /boot/config.txt

  dtoverlay=enc28j60

Now reboot the Pi

WARNING!!! - I initially got kernel panics when I tested this unit, so using a standard USB nic, you need to do the following:

  sudo apt-get update
  sudo apt-get upgrade
  sudo rpi-update (this forces a kernel update)

You can use a command line version of speedtest.net if you install it…

  sudo apt-get install python-pip
  sudo easy_install speedtest-cli
  
  Run it with speedtest-cli

I am currently getting:

4Mb/s Download
3Mb/s Upload

The best part is that it is super reliable (and cheap) and we can still use the USB port for something else :)