On 20 November 2013 22:29, Louis Lagendijk <louis@fazant.net> wrote:

On Wed, 2013-11-20 at 16:21 -0600, Kevin Martin wrote:
> On 11/20/2013 03:21 PM, Louis Lagendijk wrote:
> > Some time ago I asked a question about the broadcast address on Fedora
> > 20. On my desktop (installed from one of Alpha TC's) the interface is
> > brought up correctly, except that the broadcast address does not get set
> > correctly:
> > Ifconfig reports:
> >
> >> p5p1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
> >> inet 192.168.159.186 netmask 255.255.255.0 broadcast 0.0.0.0
> >> inet6 2001:981:688d:f2:1e6f:65ff:fed5:7742 prefixlen 128
> >> scopeid 0x0<global>
> >> inet6 fe80::1e6f:65ff:fed5:7742 prefixlen 64 scopeid
> >> 0x20<link>
> >> ether 1c:6f:65:d5:77:42 txqueuelen 1000 (Ethernet)
> >> RX packets 568712 bytes 540500284 (515.4 MiB)
> >> RX errors 0 dropped 0 overruns 0 frame 0
> >> TX packets 359977 bytes 282238000 (269.1 MiB)
> >> TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
> >
> > The broadcast address is not set when I use DHCP, but is also missing
> > when I use static address allocation. When I try a
> > ifdown p5p1; ifup05p1
> > the broadcast address is setup correctly.
> >

Interestingly enough using the iproute tools mirrors the net-tools here to some extent... although net-tools reports 0.0.0.0 whereas iproute shows no broadcast address:

2: p4p1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000

link/ether d4:be:d9:7e:f3:ce brd ff:ff:ff:ff:ff:ff

inet 10.81.10.110/24 scope global dynamic p4p1

valid_lft 18508sec preferred_lft 18508sec

inet6 fe80::d6be:d9ff:fe7e:f3ce/64 scope link

valid_lft forever preferred_lft forever

No brd bit is included in this compared to another interface that does have it:

12: virbr1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default

link/ether 52:54:00:72:fa:28 brd ff:ff:ff:ff:ff:ff

inet 192.168.244.1/24 brd 192.168.244.255 scope global virbr1

valid_lft forever preferred_lft forever

However I'm curious as to the consequences of this given that broadcast address is just a function of network address against network mask anyway ...