[arch-general] systemd network configuration

[C Anthony Risinger]

On Thu, Jul 26, 2012 at 9:56 AM, David Benfell
<benfell at parts-unknown.org> wrote:
>>
>> last command also fails.  this is one reason i had the `link up`
>> command at the end -- it always succeeds.
>>
>> what's wrong with delaying `link up` until the end?
>
> My understanding (/assumption/misconception?) was that one had to have
> an interface before one could add addresses to it.

Works For Me (tm :-)

`link up` is just enabling the interface, nothing more.  if you `link
down` a running connection, you will loose netowrk [obviously], but
it's not going to wipe out the assigned addresses:

==========================================
# ip link add bridge0 type bridge
# ip addr add 74.207.225.79/32 dev bridge0
# ip addr add 74.207.227.150/32 dev bridge0
# ip -6 addr add 2600:3c02::02:7000/64 dev bridge0
# ip -6 addr add 2600:3c02::02:7001/64 dev bridge0
# ip addr show dev bridge0
31: bridge0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN
    link/ether de:b7:12:57:2d:b9 brd ff:ff:ff:ff:ff:ff
    inet 74.207.225.79/32 scope global bridge0
    inet 74.207.227.150/32 scope global bridge0
    inet6 2600:3c02::2:7001/64 scope global tentative
       valid_lft forever preferred_lft forever
    inet6 2600:3c02::2:7000/64 scope global tentative
       valid_lft forever preferred_lft forever
# ip link set bridge0 up
# ip addr show dev bridge0
31: bridge0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue
state UNKNOWN
    link/ether de:b7:12:57:2d:b9 brd ff:ff:ff:ff:ff:ff
    inet 74.207.225.79/32 scope global bridge0
    inet 74.207.227.150/32 scope global bridge0
    inet6 2600:3c02::2:7001/64 scope global tentative
       valid_lft forever preferred_lft forever
    inet6 2600:3c02::2:7000/64 scope global tentative
       valid_lft forever preferred_lft forever
    inet6 fe80::dcb7:12ff:fe57:2db9/64 scope link tentative
       valid_lft forever preferred_lft forever
# ip link set bridge0 down
# ip addr show dev bridge0
31: bridge0: <BROADCAST,MULTICAST> mtu 1500 qdisc noqueue state DOWN
    link/ether de:b7:12:57:2d:b9 brd ff:ff:ff:ff:ff:ff
    inet 74.207.225.79/32 scope global bridge0
    inet 74.207.227.150/32 scope global bridge0
# ip link set bridge0 up
# ip addr show dev bridge0
31: bridge0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue
state UNKNOWN
    link/ether de:b7:12:57:2d:b9 brd ff:ff:ff:ff:ff:ff
    inet 74.207.225.79/32 scope global bridge0
    inet 74.207.227.150/32 scope global bridge0
    inet6 fe80::dcb7:12ff:fe57:2db9/64 scope link tentative
       valid_lft forever preferred_lft forever
# ip link delete bridge0
# ip addr show dev bridge0
Device "bridge0" does not exist.
==========================================

... well, aparantly it does wipe out ip6 addys for some reason if you
up+down+up ... but not ipv4? either thats a bug, or i don't know
enough about ipv6.

-- 

C Anthony