Installing and managing software over the network

Networked ISL across subnet boundaries

Networked ISL uses the bootp protocol. If a client machine is on a different subnet from the networked ISL server, the BOOTP gateway machine to that subnet must be able to identify the remote installation server and the client by their machine names. In addition, the installation server must be able to identify the BOOTP gateway machine by name.

The bootp protocol uses broadcast to find the server machine. Normally, broadcast is not automatically forwarded across subnet boundaries by routers. There are two possible solutions:

If the router can flag bootp protocol and pass it on, configure the router to do so. Consult the manufacturer's documentation for the router for more information.

If the router cannot flag bootp protocol, but runs on a UNIX system, use bootpgw(ADMN) (an application-level gateway for the bootp protocol):

For a gateway running SCO OpenServer software, run this command on the gateway machine:

netisl gateway on servername
where servername is the hostname of the installation server. This configures the gateway machine to use bootpgw.
To designate a different server for a given gateway machine, simply run netisl gateway on with the new server's name. The gateway machine stops sending bootp protocols to the previous server, and starts sending them to the new server. To reverse netisl gateway on completely, use netisl gateway off.
NOTE: To install any machine (including a gateway) using networked ISL, its network must include either an SCO OpenServer installation server machine or a router that forwards bootp. Therefore, if all the routers on a network run SCO OpenServer systems, you need to use networked ISL in a ``waterfall'' sequence:
1. Install an initial server from tape or CD-ROM.
2. Use networked ISL to install any routers connected to the same network, and make those routers into bootp gateways using netisl gateway on.
3. Continue in the same sequence, so that there is always a route to the installation server for bootp packets coming from any installation client.
For a router running a UNIX system other than SCO OpenServer software, add a bootpgw line to /etc/inetd.conf, as described in the bootpd(ADMN) manual page.

Once you have configured a router or gateway machine to connect the server's and client's subnets, configure the server and client for networked ISL. You will need to supply the IP address for the gateway machine.