Old style network broadcast address

[Yuwen]

Dear all,

I was not allowed to assign an IP address like 192.168.0.0/16 to a network interface in a VxWorks environment. The source code says address like 192.168.0.0 is old style broadcast address, it's not permitted. Is there any standard or document mentioning this old style broadcast address? If I use such an address in a network, what will happen?

Best regards,
Yuwen

[Barry Margolin]

Post by Yuwen
Dear all,
I was not allowed to assign an IP address like 192.168.0.0/16 to a network
interface in a VxWorks environment. The source code says address like
192.168.0.0 is old style broadcast address, it's not permitted. Is there any
standard or document mentioning this old style broadcast address? If I use
such an address in a network, what will happen?

IIRC, BSD used both 192.168.0.0 and 192.168.255.255 as the broadcast
address for the 192.168.0.0/16 network. Any network stack still
implementing that would not be able to communicate with a machine that
was assigned this IP.

[Rick Jones]

Post by Barry Margolin

Post by Yuwen
I was not allowed to assign an IP address like 192.168.0.0/16 to a
network interface in a VxWorks environment. The source code says
address like 192.168.0.0 is old style broadcast address, it's not
permitted. Is there any standard or document mentioning this old
style broadcast address? If I use such an address in a network,
what will happen?

IIRC, BSD used both 192.168.0.0 and 192.168.255.255 as the broadcast
address for the 192.168.0.0/16 network. Any network stack still
implementing that would not be able to communicate with a machine that
was assigned this IP.

*OLD* BSD - like pre 4.2 I think? And it is stretching the memory
wetware beyond its limits (and actuall hands-on experience), but I
thought that the all-zeros usage for broadcast was toast by the time
subnettting came along.

rick jones

[glen herrmannsfeldt]

Post by Rick Jones

Post by Barry Margolin

Post by Yuwen
I was not allowed to assign an IP address like 192.168.0.0/16 to a
network interface in a VxWorks environment.

(snip)

Post by Rick Jones

Post by Barry Margolin
IIRC, BSD used both 192.168.0.0 and 192.168.255.255 as the broadcast
address for the 192.168.0.0/16 network. Any network stack still
implementing that would not be able to communicate with a machine that
was assigned this IP.

*OLD* BSD - like pre 4.2 I think? And it is stretching the memory
wetware beyond its limits (and actuall hands-on experience), but I
thought that the all-zeros usage for broadcast was toast by the time
subnettting came along.

All the SunOS (pre-Solaris) that I ever used defaulted to the 0
broadcast address. As I understand it, for some years it was more usual
to run Suns on their own network, or at least their own subnet, such
that they could run that way.

We always put the right broadcast address on the ifconfig line,
especially as we usually had non-Sun machines on the same net.

As well as I know it, after using SunOS, I always put -broadcast on my
FreeBSD machines ifconfig, and probably on others, too.

-- glen

[Dick Wesseling]

Post by Rick Jones

Post by Barry Margolin
IIRC, BSD used both 192.168.0.0 and 192.168.255.255 as the broadcast
address for the 192.168.0.0/16 network. Any network stack still
implementing that would not be able to communicate with a machine that
was assigned this IP.

*OLD* BSD - like pre 4.2 I think? And it is stretching the memory
wetware beyond its limits (and actuall hands-on experience), but I
thought that the all-zeros usage for broadcast was toast by the time
subnettting came along.

Old BSD as in 8.something still treats all zeroes as broadcast, I
haven't tried FreeBSD 9 yet. Linux also treats all zeroes as broadcast.

[Rick Jones]

Post by Dick Wesseling
Old BSD as in 8.something still treats all zeroes as broadcast, I
haven't tried FreeBSD 9 yet. Linux also treats all zeroes as
broadcast.

Those are all in the receive case yes? Do any of them still allow
sending to all zeros as a broadcast?

rick jones