User`s guide

Configuring IPX Routing
How the Pipeline performs IPX routing
Pipeline User’s Guide Preliminary January 30, 1998 4-9
Watchdog spoofing
NetWare servers send out NCP watchdog packets to monitor client connections.
Clients that respond to watchdog packets remain logged into the server. If a client
does not respond to watchdog packets for a certain amount of time, the server
logs the client out.
Repeated watchdog packets can cause a WAN connection to stay active. But if
the Pipeline filters out the packets, client logins are dropped by the remote server.
To prevent repeated client logouts while allowing WAN connections to be
brought down in times of inactivity, the Pipeline responds to watchdog requests
as a proxy for remote IPX routed or bridged clients. Responding to NCP requests
is commonly called watchdog spoofing. To the server, a spoofed connection
looks like a normal, active client login session, so it does not log the client out.
When a remote client link goes down, the timer begins counting. When the value
of the Netware t/o (timeout) field is reached, the Pipeline stops responding to
watchdog packets for the client, and the connection is released by the server. If
there is a reconnection of the WAN session before the timeout value is reached,
the timer is reset.
Note:
The Pipeline software filters IPX watchdog packets automatically on all
IPX routing connections and all IPX bridging connections that have watchdog
spoofing enabled. The Pipeline applies a call filter implicitly, which prevents the
idle timer from resetting when IPX watchdog packets are sent or received. This
filter is applied after the standard data and call filters.
Automatic SPX spoofing
NetWare applications that require a guaranteed packet delivery use the NetWare
SPX protocol. This includes applications such as Print Server (PSERVER) and
Remote Printer (RPRINTER), as well as Remote Console (RCONSOLE). The
client's SPX watchdog monitors the connection with the server while the
connection is idle. To monitor the connection, the SPX watchdog sends a query
that brings up the WAN connection every 14 seconds while an SPX application is
running.
The Pipeline lets Netware SPX clients stay logged in without keeping the WAN
connection up in times of inactivity by automatically responding to SPX
watchdog requests from the LAN with a spoofed SPX-watchdog-reply packet,