James was trying to allocate a static IP address to his Pi. He did what he’d always done and allocated the static address to eth0 but was then bewildered as to why it wasn’t working. He discovered that the naming convention for network interfaces has changed in the new version of Raspbian (Stretch) to an amalgam that includes the MAC address of the Ethernet port. He’s written up his findings on his blog.
Update: This only effects brand new installs of Raspbian. So, if you upgrade your Jessie to Stretch using apt, the interface names stay the same. The interface names change, however, if you install Raspbian Stretch from scratch.
I personally think this is “a bit crap”. I know it’s becoming the ‘standard way of doing things’ but for goodness sake… To change something like this is in the “almost pointless” category in my eyes. But what do I know?
Update 6/11/2017 – Raspbian devs have listened!
The changes to the names of network interfaces has been reversed:
Changelog: Disable predictable network interface names for Ethernet devices