Ref: 17310009
Title: Fix for 3+ Share Server Crashes Due to Bursts of Corrupt Packets
date: 02/20/89

Copyright 3Com Corporation, 1991.  All rights reserved.

Transmission of bursts of corrupt packets over the network may cause a
server to crash.  Before the server crashes, you may observe these
symptoms:

  * The error message SW INT 06 appear on the server's LCD, indicating
    an attempt to execute an illegal opcode.

  * The message "Received unknown message, length ..." is added to the
    server's STATUS.LOG.  It means that 3+Share received a packet
    that did not contain the correct server message block (SMB) ID
    in the message preamble.  It may indicate packet corruption caused
    by faulty repeaters or transceivers on the network.  (To find out
    if one of these devices is producing corrupt packets, put a network
    protocol analyzer on the network to filter the corrupt packets.)

  * The errors NET804 and NET805 are displayed on a netstation,
    indicating that it has lost its links to the server.  When the
    3+Share server receives a corrupt packet from a netstation, it
    may respond by sending an SPP connection control packet, data
    stream type = FE, to terminate the session.

For 3+Share 1.6, IDP.SYS was modified to prevent 3+Share from
processing truncated packets.  The new IDP.SYS driver compares the length
specified in the IDP length field of the packet to the length reported
by the ETH driver.  If the specified IDP length is greater than the
length actually reported, the packet is discarded and SPP requests a
retransmission of the bad packet from the source.  Because the truncated
packets are not processed by 3+Share, the server should not fail when
bursts of corrupt packets are produced.

The latest release of the IDP.SYS and SPP.SYS drivers are available in
the Ask3Com forum, Patches and Fixes library, in the file DRIVRS.ZIP.

