Specifications

©
2002, David K. Z. Harris
32
Pg. 32
© 2002
David K. Z. Harris
Adding a Console Server App
Ø Combination Server (CS/TS)
² Logging server equipped with multi-
port serial card(s)
Ø Separate Server Devices
² Console Server App on the network
² Terminal servers attach to devices
Ø How to decide which is best?
Some console server applications allow you to add some multi-port serial
interface cards, and attach serial consoles directly to the console server. In the
preceding illustration, we showed this as “CS/TS”, because the Console Server
is also performing the serial attachment duties of the Terminal Server.
Conserver can support this mode, although we don’t normally recommend it,
except in small, non-production environments, because you are usually going
to be limited by how many serial ports can be hosted on the CPU. (This is a
function of the number of spare slots, and the number of poets per card. You
wouldn’t usually see more than 96 ports on a single server in this mode.)
A secondary concern, in our mind, is that the serial ports will normally send a
serial BREAK signal when you power-cycle the CPU. In a Sun environment,
that signal on the console will halt the server, and you’ll have to wait until the
CPU boots before you can get back on each console individually and type
“go”.
The main advantage of this mode is that the logging traffic is kept within the
computer, rather than on the network between the terminal server and the
console server. (The network load is only partially reduced, since the client
sessions still traverse the network to get to the console server.)
As a result, the security issues of sniffing the logging traffic is also reduced,
but the client sessions are still exposed, unless the client can use SSL or SSH
for the connection to the console server.