Configuring Broadcast Settings
19-16
IP Configuration
Configuring Broadcast Settings
Purpose
To
configure
IP
broadcast
settings.
By
default,
interfaces
on
the
SecureStack
C3
do
not
forward
broadcast
packets.
Commands
ip directed-broadcast
Use
this
command
to
enable
or
disable
IP
directed
broadcasts
on
an
interface.
By
default,
interfaces
on
the
SecureStack
C3
do
not
forward
directed
broadcasts.
The
no
form
of
this
command
disables
IP
directed
broadcast
on
the
interface.
Syntax
ip directed-broadcast
no ip directed-broadcast
Parameters
None.
Defaults
None.
Mode
Interface
configuration:
C3(su)
‐
>Router1(Config
‐
if(Vlan
1))#
Usage
Directed
broadcast
is
an
efficient
mechanism
for
communicating
with
multiple
hosts
on
a
network
while
only
transmitting
a
single
datagram.
A
directed
broadcast
is
a
packet
sent
to
all
hosts
on
a
specific
network
or
subnet.
The
directed
broadcast
address
includes
the
network
or
subnet
fields,
with
the
binary
bits
of
the
host
portion
of
the
address
set
to
one.
For
example,
for
a
network
with
the
address
192.168.0.0/16,
the
directed
broadcast
address
would
be
192.168.255.255.
For
a
subnet
with
the
address
192.168.12.0/24,
the
directed
broadcast
address
would
be
192.168.12.255.
In
order
to
minimize
broadcast
DoS
attacks,
forwarding
of
directed
broadcasts
is
disabled
by
default
on
the
SecureStack
C3,
as
recommended
by
RFC
2644.
If
the
ability
to
send
directed
broadcasts
to
a
network
is
required,
you
should
enable
directed
broadcasts
only
on
the
one
interface
that
will
be
transmitting
the
datagrams.
For
example,
if
a
SecureStack
C3
has
five
routed
interfaces
for
the
10,
20,
30,
40,
and
50
networks,
enabling
directed
For information about...
Refer to page...
ip directed-broadcast
19-16
ip forward-protocol
19-17
ip helper-address
19-18
Summary of Contents for SECURESTACK C3
Page 2: ......
Page 34: ...xxxii...
Page 40: ...Getting Help xxxviii About This Guide...
Page 126: ...clear license 4 6 Activating Licensed Features...
Page 132: ...set port inlinepower 5 6 Configuring System Power and PoE...
Page 228: ...clear port protected name 7 60 Port Configuration...
Page 270: ...clear snmp interface 8 42 SNMP Configuration...
Page 396: ...clear port txq 12 10 Port Priority Configuration...
Page 414: ...ip igmp robustness 13 18 IGMP Configuration...
Page 542: ...clear arpinspection statistics 17 32 DHCP Snooping and Dynamic ARP Inspection...
Page 546: ...Enabling Router Configuration Modes 18 4 Preparing for Router Mode...
Page 640: ...traceroute ipv6 21 10 IPv6 Management...
Page 698: ...show ipv6 dhcp binding 24 20 DHCPv6 Configuration...
Page 746: ...show ipv6 ospf virtual link 25 48 OSPFv3 Configuration...
Page 834: ...ip access group 26 88 Authentication and Authorization Configuration...
Page 848: ...TACACS Configuration clear tacacs interface 27 14...
Page 866: ...sFlow Configuration show sflow agent 28 18...
Page 872: ...Index 4...