Configuring Load Sharing Network Address Translation (LSNAT)
19-4 LSNAT Configuration
the
UDP
port.
If
the
server
responds
with
an
ICMP
“Port
Unreachable”
message,
it
is
concluded
that
the
port
is
not
active
and
the
server
is
reported
as
“DOWN”.
Otherwise,
if
the
server
either
gets
data
back
from
the
request
to
the
server
or
does
not
get
any
response
at
all,
it
is
assumed
that
the
port
is
active
and
the
server
is
reported
as
“UP”.
The
lack
of
a
response
could
also
be
the
result
of
the
server
itself
not
being
available
and
could
produce
an
erroneous
indication
of
the
server
being
“UP”.
To
avoid
this
when
requesting
an
APP
UDP
on
a
UDP
port,
an
ICMP
ping
is
issued
first
to
insure
that
the
server
is
available
before
submitting
the
APP
UDP
request.
This
prevents
a
situation
where
the
UDP
port
will
not
return
a
“Port
Unreachable”
because
of
the
server
itself
being
down,
resulting
in
LSNAT
responding
with
a
false
indication
that
the
UDP
port
is
“UP”.
Application Content Verification (ACV)
Application
Content
Verification
(ACV)
can
be
enabled
on
a
port
to
verify
the
content
of
an
application
on
one
or
more
load
balancing
servers.
ACV
is
a
method
of
ensuring
that
data
coming
from
your
servers
remains
intact
and
does
not
change
without
your
knowledge.
ACV
can
simultaneously
protect
against
server
outages,
accidental
file
modification
or
deletion,
and
servers
whose
security
have
been
compromised.
By
nature,
ACV
is
protocol
independent
and
is
designed
to
work
with
any
type
of
server
that
communicates
via
formatted
ASCII
text
messages,
including
HTTP,
FTP,
and
SMTP.
For
ACV
verification,
you
specify
the
following:
•
A
string
that
the
router
sends
to
a
single
server.
The
string
can
be
a
simple
HTTP
command
to
get
a
specific
HTML
page,
or
it
can
be
a
command
to
execute
a
user
‐
defined
CGI
script
that
tests
the
operation
of
the
application.
•
The
reply
that
the
application
on
each
server
sends
is
back
used
by
the
router
to
validate
the
content.
In
the
case
where
a
specific
HTML
page
is
retrieved,
the
reply
can
be
a
string
that
appears
on
the
page,
such
as
“OK”.
If
a
CGI
script
is
executed
on
the
server,
it
should
return
a
specific
response
(for
example,
“OK”)
that
the
router
can
verify.
ACV
works
by
sending
a
command
to
your
server
and
searching
the
response
for
a
certain
string.
If
it
finds
the
string,
the
server
is
marked
as
Up.
If
the
string
is
not
found,
the
server
is
marked
as
Down.
For
example,
if
you
sent
the
following
string
to
your
HTTP
server,
“HEAD
/
HTTP/
1.1\\r\\nHost:
www.enterasys.com\\r\\n\\r\\n”,
you
could
expect
to
get
a
response
of
a
string
returned
similar
to
the
following:
HTTP/1.1 200 OK
Date: Tue, 11 Dec 2007 20:03:40 GMT
Server: Apache/2.0.40 (Red Hat Linux)
Last-Modified: Wed, 19 Sep 2007 13:56:03 GMT
ETag: “297bc-b52-65f942c0”
Accept-Ranges: bytes
Content-Length: 2898
You
can
search
for
a
reply
string
of
“200
OK”
this
would
result
in
a
successful
verification
of
the
service.
Because
ACV
can
search
for
a
string
in
only
the
first
255
bytes
of
the
response,
in
most
HTTP
cases
the
response
will
have
to
be
in
the
packet
ʹ
s
HTTP
header
(i.e.,
you
will
not
be
able
to
search
for
a
string
contained
in
the
web
page
itself).
Some
protocols
such
as
FTP
or
SMTP
require
users
to
issue
a
command
to
close
the
session
after
making
the
request.
A
faildetect
acv
‐
quit
command
allows
for
the
input
of
the
quit
string
required.
Содержание Enterasys Matrix DFE-Gold Series
Страница 1: ...P N 9033933 15 Enterasys Matrix DFE Gold Configuration Guide Firmware Version 6 11 xx...
Страница 2: ......
Страница 40: ...Getting Help xxxviii About This Guide...
Страница 148: ...Reviewing and Configuring Routing router 2 106 Startup and General Configuration...
Страница 300: ...Configuring SNMP Walk Behavior set snmp timefilter break 5 42 SNMP Configuration...
Страница 378: ...Configuring Spanning Tree Loop Protect Features show spantree nonforwardingreason 6 78 Spanning Tree Configuration...
Страница 456: ...Configuring Policy Based Routing ip policy pinger 8 50 Policy Classification Configuration...
Страница 576: ...Configuring NetFlow clear netflow template 15 12 NetFlow Configuration...
Страница 610: ...Configuring Debug IP Packet no debug ip packet 16 34 IP Configuration...
Страница 640: ...Configuring Network Address Translation NAT clear router limits NAT 18 18 Network Address Translation NAT Configuration...
Страница 676: ...Configuring Load Sharing Network Address Translation LSNAT clear router limits LSNAT 19 36 LSNAT Configuration...
Страница 804: ...TWCB Configuration Example clear router limits TWCB 23 22 Transparent Web Cache Balancing Configuration...
Страница 922: ...Understanding RADIUS Snooper show radius snooping session 26 12 RADIUS Snooping Configuration...
Страница 940: ...Configuring Multiple Authentication show multiauth trap 27 18 MultiAuth Configuration...
Страница 944: ...Index 4...