[Malvern] Ubuntu 14.10 - 70-persistent-net.rules

[ken at shail.co.uk]

I have a problem with network set-up on Ubuntu 14.10 server and wondered if 
any of the group have experience with this issue. I have googled and found 
quite that it is quite common but no one has provided a complete answer. It 
looks like the well tried and reliable network set-up has now been bust.

It starts with the LAN interface being allocated p1p1 and p4p1 (I have two 
on this board) instead of eth0 and eth1.
It appears that /etc/udev/rules.d/70-persistent-net.rules is not being 
written to like it used to by the udev startup action and that the system 
creates p1p1 and p4p1as substitutes. It will work in this configuration as 
long as it is left in auto-DHCP configuration. The problem come when 
allocating mixed auto and manual settings.

The work-around seems to be to create 70-persistent-net.rules manually using 
the MAC addresses of the two interfaces then populating 
/etc/network/interfaces manually.
This works fine if both are manual (static IP) but if one is static and the 
other uses DHCP the boot sequence waits for 60 seconds for the one with DHCP 
to find its setting when no cable is connected to that port. If a cable is 
connected it will find settings as usual from the DHCP server but then 
refuses to send packets. They all have to go via the port that has the 
static IP.

It all seems a bit of a hack and the real reason is not apparent. I.E. why 
/etc/udev/rules.d/70-persistent-net.rules is not being written to 
automatically.

I have installed Mint 17.1 and the same applies, presumably because it is 
Debian based.

Any thoughts would be appreciated.

Ken Shail