This code is still less than perfect and undoubtedly has bugs.  As of this
release, the following are considered *serious* bugs: 

* Transport mode with compression is broken.  The workaround is to either
omit compression or use tunnel mode (which is preferable anyway).

* There is a very obscure bug that sometimes causes Pluto to hang.  We
have not been able to reproduce it well, and the information so far seems
to suggest misbehavior by the Linux kernel's select() call.  It's not new,
so if it hasn't bothered you so far, it probably won't start bothering
you now.

* If there are multiple connections specified between the same two
security gateways, either all or none must specify compression.  Otherwise
the result is unpredictable. 

* Installing a new FreeS/WAN on top of an old one doesn't update kernel
configuration options, so if new options are added, you need to start
with a virgin kernel instead.

* KLIPS cannot cope with IP packets employing IP options.

* There are some ill-defined problems with sending large packets through
transport-mode connections, especially in 2.2.xx kernels.

* There appears to be a kernel memory leak if rekeying occurs while a
connection is carrying traffic.  The effect is small unless you are
rekeying very frequently indeed.

* There are too many ways for packets to get around the security stuff. 
In particular, suppose you have the following, with security gateways X
and Y serving subnets S and T: 

        S======X........Y======T

A packet which shows up at Y, in clear text, claiming to be from S, with a
destination in T, will be forwarded... even if there is an IPSEC tunnel
between X and Y which ought to be encrypting all such packets.  The damage
such packets could do is limited, but denial-of-service attacks are an
obvious possibility.  Dealing with this is difficult in general, because
we aren't quite close enough to the center of the IP processing machinery.
KLIPS2 should fix this.

* Another "packet leak" arises because at startup, shutdown, or restart,
there is a brief period when the network is up but IPSEC is not.  This
exposure can be reduced using the forwardcontrol parameter. 

* A similar leak occurs because there is no simple way to *replace* a
route using the Linux 2.2.xx route(8) command.  It has to be done with a
delete/add sequence, which leaves a timing window in which there is no
route for the destination.  (KLIPS2 should remove this problem, which is
why we haven't sweated hard on a workaround.)

* Minor difficulties can arise if more than one subnet is behind a single
security gateway, e.g.: 

        S======X.........Y======T
                         \\
                           ======U

If U wants to talk to S encrypted, but T wants to talk to S in clear (no
IPSEC), it actually is possible... but it has to be done with manual
"keying", which is a little messy if the U-S connection is automatically
keyed, because the two connections share a route but Pluto is not aware
of this.

* The number of IPSEC interfaces is hardcoded at 4 rather than being
configurable (although at least it's not 2 any more).



This file is RCSID $Id: BUGS,v 1.41 2001/06/19 05:07:59 henry Exp $