From: k@hprnd.rose.hp.com (Steve Kao)
Newsgroups: comp.periphs.printers
Subject: HP-UX, Unix LaserJets, and Routers
Date: 13 Aug 92 00:04:15 GMT
Organization: HP Roseville Networks Division


            JETDIRECT FOR UNIX AND ROUTERS ON HP-UX NETWORKS

Some people want to have the JetDirect for unix card in a LaserJet
printer/plotter on one network segment, and a Master Spooler on a
different network segment.  Between the two segments is a router.  Below
is a picture of such a set-up.

     +------+
     |Node A| IP=15.32.151.6
     |HP9000| Subnet Mask=255.255.248.0
     +---+--+
         |
---------+--------------------------+-----------------------------------
                                    |
                                 +--+--+
                                 |lan 0| IP=15.32.150.3
                                 |     | Subnet Mask=255.255.248.0
                                 |-----|
                   IP=192.6.2.10 |lan 1|
       Subnet Mask=255.255.255.0 |     |
                                 +--+--+
                                    |
------------------------------------+---------+-------------------------
                                              |
                                         +----+---+
                                         |LaserJet| IP=192.6.2.11
                                         +--------+ Subnet Mask=255.255.255.0

In order for Node A to be a Master Spooler, the following things need to
be configured.  On the LaserJet (it could be a DesignJet plotter, but
I'm using a LaserJet in this example), the subnet mask must be
configured to be the same as all other devices on lan 1.  The gateway
parameter must contain the IP address of the router's lan 1 IP address.
The /etc/bootptab file forthe LaserJet must look something like the
following.

hplaser1:\
	:ht=ether:\
	:ha=080009cba987:\
	:gw=192.6.2.10:\
	:sm=255.255.255.0:\
	:hn:\
	:vm=rfc1048:

You must configure both the "gw" and the "sm" parameters.  Without the
"sm" parameter, the LaserJet will use the default subnet mask of 0.0.0.0
and not recognize the "gw" parameter as having any meaning.  The "gw"
parameter is needed to tell the LaserJet that packets may be sent to the
printer from a different network segment.  (Use your card's LAN hardware
address for the "ha" parameter.)

On Node A (the Master Spooler), an entry must be made to /etc/netlinkrc
to point to the router's lan 0 IP address (15.130.150.3 in this case).
This is a large file.  Look for a section in the file similar to the
following.

#
# Initialize network routing.
#
# (STEP 2) (OPTIONAL, FOR NETWORKS WITH GATEWAYS ONLY)
#
# The route(1m) command manipulates the network routing tables.
# The "case $NODENAME" construct below allows each node in a diskless
# cluster to execute node specific route calls if necessary.  Add entries
# to the case construct for specific nodes in the diskless cluster if needed.
#
# For example,
#
#   case $NODENAME in
#     $ROOTSERVER) /etc/route add 192.0.2 gatenode 1
#                  ;;
#               *) /etc/route add default 15.2.104.69 1
#                  ;;
#   esac
#
# adds network destination "192.0.2" to the rootserver's routing tables,
# indicating a correspondence between that destination and the gateway
# "gatenode", and specifying the number of hops to the gateway as 1.  For 
# all other nodes (* is the wildcard), the default gateway is set to 
# 15.2.104.69. 
#
# The route command should be invoked once per gateway. 
#
# SEE ALSO: route(1m), routing(7)

case $NODENAME in
            *) /etc/route add default 15.32.150.3
               ;;
esac


                         BOOTP THROUGH THE ROUTER

When the card is powered up, it knows nothing about itself, not even its
IP address.  After initializing itself, it checks to see where it gets
its configuration information.  If its configuration information comes
from bootp (as opposed to from the front panel), then the card
broadcasts a bootp request.  If the bootp server is on the same subnet
and has been configured to respond to bootp requests from the card's LAN
hardware address, then the bootp server sends the bootp configuration to
the card in a bootp reply.  If the bootp server is on a different
subnet, then the router(s) between the two subnets must be able to
forward the broadcast bootp request between the subnets.  By default,
most routers do not forward broadcast packets.  The ability to forward
bootp broadcast requests is called "bootp relay."

If the router in the above example does not support bootp relay, then
the bootp server for the LaserJet must be on the LaserJet's local
network segment.  In order for the Master Spooler (or any other system
on the 15.32.144 subnet) to be the bootp server, the router must
support bootp relay.  Not all routers support bootp relay.  Some
routers must be configured to support bootp relay.  Some routers (such
as the HP27270A router CR) support bootp relay only after certain
firmware revisions (rev. 5.74 for the router CR).

- Steve Kao
This is NOT an official response of Hewlett-Packard