On Thu, Jun 01, 2017 at 09:08:45AM +0200, Matthias May wrote: > On 31/05/17 18:29, Greg Rose wrote: > > On Wed, 2017-05-31 at 08:32 -0700, Ben Pfaff wrote: > >> On Wed, May 31, 2017 at 11:39:28AM +0200, Matthias May wrote: > >>> On 27/05/17 04:29, Hunt Xu wrote: > >>>> On Fri, May 26, 2017 at 11:46 PM, Ben Pfaff <[email protected]> wrote: > >>>>> It's becoming more common that OSes include "ip" but not "ifconfig", so > >>>>> it's best to avoid using the latter. This commit removes most > >>>>> references > >>>>> to "ifconfig" and replaces them by "ip". It also adds a build-time > >>>>> check > >>>>> to make it harder to introduce new uses of "ifconfig". > >>>>> > >>>>> Signed-off-by: Ben Pfaff <[email protected]> > >>>>> --- > >>>> > >>>> <snip> > >>>> > >>>>> diff --git a/Documentation/faq/issues.rst b/Documentation/faq/issues.rst > >>>>> index c60336a10569..82d0605da125 100644 > >>>>> --- a/Documentation/faq/issues.rst > >>>>> +++ b/Documentation/faq/issues.rst > >>>>> @@ -43,8 +43,8 @@ eth0. Help! > >>>>> itself. For example, assuming that eth0's IP address is > >>>>> 192.168.128.5, you > >>>>> could run the commands below to fix up the situation:: > >>>>> > >>>>> - $ ifconfig eth0 0.0.0.0 > >>>>> - $ ifconfig br0 192.168.128.5 > >>>>> + $ ip addr flush dev eth0 > >>>>> + $ ip addr add 192.168.128.5 dev br0 > >>>> > >>>> ip addr add 192.168.128.5/24 dev br0 > >>>> > >>>> It seems using ifconfig without specifying any netmask the > >>>> netmask/prefixlen > >>>> will still be properly set (not diving quite deep, but strace indicates > >>>> that > >>>> this is not done by ifconfig, ifconfig don't even try to set the > >>>> netmask), > >>>> whlie using ip-address with only the address specified the prefixlen is > >>>> always 32. > >>>> > >>>> Some tests on my Ubuntu 16.04: > >>>> 1a. ifconfig br0 192.168.128.5 -> br0 gets 192.168.128.5/24 > >>>> 1b. ip addr add 192.168.128.5 dev br0 -> br0 gets 192.168.128.5/32 > >>>> 2a. ifconfig br0 172.16.128.5 -> br0 gets 172.16.128.5/16 > >>>> 2b. ip addr add 172.16.128.5 dev br0 -> br0 gets 172.16.128.5/32 > >>>> 3a. ifconfig br0 10.0.128.5 -> br0 gets 10.0.128.5/8 > >>>> 3b. ip addr add 10.0.128.5 dev br0 -> br0 gets 10.0.128.5/32 > >>>> > >>>>> > >>> *snip* > >>> > >>> You might want to consider to add brd + to the ip command. > >>> E.g. ip addr add 192.168.128.5/24 brd + dev br0 > >>> > >>> Without: > >>> 7: br0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group > >>> default qlen 1000 > >>> link/ether 1a:78:fe:72:9c:be brd ff:ff:ff:ff:ff:ff > >>> inet 192.168.128.5/24 scope global br0 > >>> valid_lft forever preferred_lft forever > >>> > >>> With: > >>> 7: br0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group > >>> default qlen 1000 > >>> link/ether 1a:78:fe:72:9c:be brd ff:ff:ff:ff:ff:ff > >>> inet 192.168.128.5/24 brd 192.168.128.255 scope global br0 > >>> valid_lft forever preferred_lft forever > >>> > >>> As you can see the broadcast address isn't set without. > >>> > >>> I see you already posted a v4 but this comment seems more appropriate in > >>> this thread. > >> > >> What happens if no broadcast address is specified? I've never seen > >> instructions say that one should specify this, so I really wonder > >> whether it is necessary. > > > > My understanding of this is that the brd command is used to over ride > > the broadcast address that would normally be computed by specifying the > > IP/CIDR. I don't think it is necessary and I don't generally specify it > > in normal usage. > > > > Thanks, > > > > - Greg > > Well it may not be needed from a technical point of view, but the output > differs compared to when the address is added > with ifconfig. > brd + also automatically sets the broadcast address based on netmask and > address, and the output then is identical to > when the address is set with ipconfig.
It's true. If it turns out to cause a problem, we'll try adding it. _______________________________________________ dev mailing list [email protected] https://mail.openvswitch.org/mailman/listinfo/ovs-dev
