IBM Tivoli Access Manager for e-business: WebSEAL Administration ...

v
“Modifying
request-body-max-read”
Server-side
cache
parameters
are
also
summarized
in
the
configuration
file
reference
appendix.
See
“Server
configuration”
on
page
384.
Modifying
max-client-read
This
parameter
specifies
the
maximum
number
of
bytes
that
WebSEAL
holds
in
internal
buffers
while
reading
from
a
client.
It
affects
the
maximum
size
of
URLs,
HTTP
Headers,
and
the
size
of
a
request
that
will
be
cached.
This
parameter
must
be
set
to
at
least
twice
the
value
of
request-body-max-read.
The
minimum
value
is
32768.
If
the
value
is
set
to
a
number
below
32768,
the
value
is
ignored
and
a
value
of
32768
is
used.
The
default
value
is
32768
[server]
max-client-read
=
32768
This
value
can
be
increased
when
your
deployment
needs
to
cache
abnormally
large
requests.
There
is
no
maximum
size
other
than
the
maximum
imposed
by
the
data
type.
However,
increasing
the
size
can
possibly
adversely
affect
performance
and
system
security.
Allocating
larger
buffers
increases
memory
usage
and
thus
could
possibly
decrease
performance.
More
importantly,
allocating
very
large
buffers
increases
the
risk
of
a
successful
denial-of-service
attack
by
a
malicious
user.
The
risk
is
increased
simply
because
WebSEAL
is
loading
and
holding
more
data
into
memory,
which
provides
the
user
with
a
larger
buffer
from
which
to
attempt
an
attack.
Modifying
request-body-max-read
This
parameter
specifies
the
maximum
number
of
bytes
to
read
in
as
content
from
the
body
of
requests
for
use
in
dynurl,
authentication,
and
request
caching.
This
affects
the
amount
of
data
that
WebSEAL
caches
for
users
who
must
authenticate
before
their
request
can
be
fulfilled.
This
affects
all
request
that
have
bodies,
such
as
POST
and,
PUT
requests.
This
impacts
forms
authentication,
because
this
limits
the
size
of
the
POST
data
that
is
processed
when
performing
such
authentication.
To
maintain
a
request
body
size
sufficient
for
forms
authentication,
WebSEAL
sets
a
hard
minimum
of
512
bytes
on
request-body-max-read.
When
this
value
is
set
below
that
minimum,
the
setting
will
be
ignored
and
the
value
512
is
used.
This
setting
also
impacts
dynamic
URL
processing
because
the
query
portion
of
a
POST
request
URI
is
contained
in
the
request
body.
Note:
This
setting
does
not
limit
the
maximum
POST
size.
The
maximum
POST
size
is
unlimited.
The
value
of
request-body-max-read
is
related
to
the
value
of
max-client-read.
When
request-body-max-read
is
set
to
a
value
higher
than
16384,
max-client-read
must
be
increased
to
at
least
twice
the
value
of
request-body-max-read.
When
the
value
of
max-client-read
is
less
than
double
the
value
of
request-body-max-read,
WebSEAL
ignores
request-body-max-read
and
imposes
a
value
of
half
the
value
of
max-client-read.
The
default
value
is
4096:
[server]
request-body-max-read
=
4096
You
can
set
this
parameter
to
zero
(0).
202
IBM
Tivoli
Access
Manager
for
e-business:
WebSEAL
Administration
Guide