orpheus <[EMAIL PROTECTED]> wrote:
>
> The connection is made OK, and the protocol headers are exchanged but
> nothing else - for example in the POP3 case USER and PASS are sent,
> but after RETR is issued I get the size of the message and no data.

This problem is reported regularly on this list, and it can have a
couple of different causes.  The basic problem is that small packets are
getting through just fine, but large packets are not.

One reason for this might be that the packets are getting fragmented
during their travel across the net, and the masquerade system cannot
figure out how to route the fragments to the final destination, because
the port and control information is only found in the first packet; the
other packets don't have enough information to identify that they are to
be masqueraded.  This can be rectified, though, by configuring your masq
box to re-assemble fragments before forwarding them on.  The kernel
option for this is CONFIG_IP_ALWAYS_DEFRAG.

Another reason is a bit more mysterious, and involves routers that have
different MTU sizes, and dropping of packets that don't happen to match
the size they expect.  I've never heard an explanation that satisifies
me about this problem, but I do know that the solution involves setting
your own MTU size to match what is typical for an ethernet config-
uration.  That is, on your PPP (and of course, your ethernet) interface,
make sure the MTU is set to 1500.

-- 
   [EMAIL PROTECTED] (Fuzzy Fox)      || "Nothing takes the taste out of peanut
sometimes known as David DeSimone  ||  butter quite like unrequited love."
  http://www.dallas.net/~fox/      ||                       -- Charlie Brown
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