5
Routing
91
Example: Adding a route with LocalIP
This
example
will
show
adding
a
route
for
the
network
10.2.2.0/24
on
the
interface
sfp1
with
LocalIP
set
as
10.2.2.1
.
Device:/>
cc
RoutingTable
main
Device:/RoutingTable/main>
add
Route
Interface=sfp1
Network=10.2.2.0/24
LocalIP=10.2.2.1
Device:/RoutingTable/main>
cc
Device:/>
All traffic must have two associated routes
All
traffic
must
have
two
routes
associated
with
it.
Not
only
must
a
route
be
defined
for
the
destination
network
of
a
flow,
but
one
must
also
be
defined
for
the
source
network.
The
route
that
defines
the
source
network
simply
says
that
the
source
network
is
found
on
a
particular
interface.
When
a
new
flow
is
opened,
the
SEG
performs
a
check
known
as
a
reverse
route
lookup
,
which
looks
for
this
route.
The
source
network
route
is
not
used
to
perform
routing
but
instead
is
used
to
verify
that
the
source
network
is
found
on
the
interface
where
it
arrived.
If
this
check
fails,
the
SEG
generates
a
Default
Access
Rule
error
log
message.
Even
traffic
destined
for
Core
(the
SEG
itself),
such
as
ICMP
ping
requests
must
follow
the
rule
of
having
two
routes
associated
with
it.
In
this
case,
the
interface
of
one
of
the
routes
is
specified
as
Core
.
Static routing
The
most
basic
form
of
routing
is
known
as
Static
Routing
.
The
term
“static”
is
used
because
most
entries
in
a
routing
table
are
part
of
the
SEG
system’s
static
configuration.
They
usually
remain
unchanged
during
long
periods
of
system
operation.
Due
to
this
manual
approach,
static
routing
is
most
appropriate
to
use
in
network
deployments
where
addresses
are
fairly
fixed
and
where
the
amount
of
connected
networks
are
limited
to
a
few.
This
section
describes
how
to
configure
static
routing
and
also
explains
how
routing
is
implemented
in
the
SEG.
The
SEG
supports
multiple
routing
tables.
A
default
table
called
main
is
predefined
and
is
always
present
in
the
SEG.
However,
you
can
also
define
additional
and
completely
separate
routing
tables
to
provide
alternate
routing.
Route lookup mechanism
The
SEG
route
lookup
mechanism
has
some
slight
differences
from
how
some
other
router
products
work.
In
many
routers,
when
the
IP
packets
are
forwarded
without
context
(in
other
words,
the
forwarding
is
stateless),
the
routing
table
is
scanned
for
each
and
every
IP
packet
received
by
the
router.
In
the
SEG,
packets
are
forwarded
with
state
‐
awareness,
so
the
route
lookup
process
is
tightly
integrated
into
the
SEG
stateful
inspection
mechanism.
