Connecting Raspberry Pi Zeros over Ethernet

Question

I'm attempting to set up a simple network made up of two raspberry pi zeros, one with wifi to access over ssh by another computer and then communication between the two pis using Ethernet. To set up the pi with wifi access I used this guide: https://www.raspberrypi.org/documentation/configuration/wireless/access-point.md

To add two Ethernet ports I followed the directions below: https://raspi.tv/2015/ethernet-on-pi-zero-how-to-put-an-ethernet-port-on-your-pi

To summarize my issue:

• I can connect using wifi to the first pi without issue.
• I can plug each pi into the Ethernet jack of another computer and ssh into the device using avahi.
• With the two pis connected over Ethernet I cannot ssh into one and then to the other over Ethernet.
• I have set this up before using pis with Ethernet built in, e.g. Pi3, Pi4.

If anyone can help that would be fantastic, thanks!

Edit: As @Mark wrote the problem is that I was using a straight through cable and not a cross over for these Ethernet modules. The Ethernet modules use the ENC28J60 chip for those who might come across this issue in the future.

Answer 1

Assuming you're using the hardware mentioned in the "raspi.tv" article, the problem is that you're using an Ethernet straight-through cable when you need a crossover cable.

Gigabit Ethernet ports have "auto-crossover"/"auto-uplink" functionality built in, so you can connect any two ports using any type of cable, but older hardware, like the 10Base-T controller you're using, doesn't. If you use a straight-through cable to attach two computers both using this older hardware, you're connecting the transmit pins to each other and the receive pins to each other, and no data can get through. A crossover cable connects the transmit pins on one end to the receive pins on the other, and things work as expected.