released the Arduino Ethernet Library version 2.0.0, for all Arduino boards (not just Teensy).

Version 2.0.0 adds many new features and greatly improves performance. Here’s a detailed look at what’s new.

Auto-Detect Hardware
All 3 SPI-based chips from Wiznet, W5100, W5200, and W5500 are supported. Ethernet.begin() automatically detects which chip you have connected.

Version 2.0.0 greatly improves performance. Optimizations at multiple levels within the library work together to vastly improve performance, especially on the oldest W5100 hardware, and also make the most of the newer W5200 and W5500 chips.

The Wiznet chips transmit and receive Ethernet packets with their internal buffer memory.

W5100 chips see a tremendous TCP speed boost, because the delayed ACK feature was poorly implemented in that old chip. Even W5200 & W5500 speed is improved, especially when larger buffers are used.

Block Mode For Data Transfer

EthernetClient has 3 new functions similar to the ones from EthernetUDP. The remoteIP() function is very nice after connecting, if you used a name and DNS found the IP number.

EthernetServer now has an accept() function, for use by more advanced projects. The traditional available() function would only tell you of a new client after it sent data, which makes some protocols like FTP impossible to properly implement.

[Kristopher Marciniak] designed and built an inexpensive device that verifies the basics:

Is the link up? Is this cable connected?
Can it get a DHCP address?
Can it perform a DNS lookup?
Can it open a webpage?

What’s going on under the hood? A Raspberry Pi, you’d think. A BeagleBoard? Our hearts were warmed to see a throwback to a more civilized age: an ENC28J60 breakout board and an Arduino Uno. That’s right, [Kristopher] replicated a couple-hundred dollar network tester for the price of a few lattes.

LinkTrucker
https://hackaday.io/project/9229-linktrucker

Inspired by other hardware, this Arduino UNO and ENC28J60 checks your Ethernet Link, DHCP, DNS, and connects to a server for < $25!

The Arduino initializes the Ethernet Module and shows a link or not. It then tries to get a DHCP address (if none defaults to stored IP and warns you). Then it connects to Google DNS at 8.8.4.4 and looks up our friendly neighborhood time server "0.pool.ntp.org" (if it can't find it it warns you). Finally it makes a web connection to "www.google.com" (if it can't it warns). So all green lights mean that we got an IP and we can see then internet!