iftab -> persistent rules transition can break existing setups

[Jürgen Kreileder]

Binary package hint: udev

The switch from /etc/iftab to /etc/udev/rules.d/70-persistent-net.rules can break existing setups. There should be an automatic conversion of rules or at least a warning in NEWS.

My iftab assigned 'lan' and 'wifi' to the interfaces on my laptop. These interfaces names are used by the firewall setup (shorewall).
After upgrading udev, the interfaces were named 'eth0' and 'eth1' because of the new rules and the firewall blocked all traffic.

[Scott James Remnant (Canonical) (canonical-scott)]

Automatic conversion is planned

[Scott James Remnant (Canonical) (canonical-scott)]

udev (113-0ubuntu15) gutsy; urgency=low

  * Ship the UUID migration script as a separate executable, called by
    volumeid's postinst; also ensure we don't call it when installing the
    base system on the LiveCD (oops!)
  * Migrate /etc/fstab settings to the new rules generator. LP: #125139.

 -- Scott James Remnant <email address hidden> Wed, 03 Oct 2007 16:07:58 +0100

[Claus Frein (cfrein)]

On upgrading from feisty to gutsy with a do-release-upgrade iftab was not correctly converted.

The former mac-address in iftab was uppercase, but udev refers to lowercase and so created a new device:
---
> cat /etc/udev/rules.d/70-persistent-net.rules

# Converted from /etc/iftab on upgrade
SUBSYSTEM=="net", DRIVERS=="?*", ATTRS{address}=="00:0C:29:F1:74:5D", NAME="eth0"

# PCI device 0x1022:0x2000 (pcnet32)
SUBSYSTEM=="net", DRIVERS=="?*", ATTRS{address}=="00:0c:29:f1:74:5d", NAME="eth1"

---
>cat /etc/iftab
##eth0 mac 00:0C:29:F1:74:5D
---

This broke the network-configuration of the server.