Nortel Networks 4050 Manuale Utente

38 Chapter 1 Overview

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Communications between the Nortel SNAS 4050 and key elements of the Nortel 
SNA solution are secure and encrypted. 

 shows the communication 

channels in the network.

Telnet or SSH can be used for management communications between remote PCs 
and the Nortel SNAS 4050 devices.

The Secure Shell (SSH) protocol provides secure and encrypted communication 
between the Nortel SNAS 4050 and the network access devices, and between 
Nortel SNAS 4050 devices and remote management PCs not using Telnet.

SSH uses either password authentication or public key authentication. With public 
key authentication, pairs of public/private SSH host keys protect against “man in 
the middle” attacks by providing a mechanism for the SSH client to authenticate 
the server. SSH clients keep track of the public keys to be used to authenticate 
different SSH server hosts.

SSH clients in the Nortel SNA network do not silently accept new keys from 
previously unknown server hosts. Instead, they refuse the connection if the key 
does not match their known hosts. 

Communication channels in the Nortel SNA network

Between Nortel SNAS 4050 and edge 
switches

SSH

Between Nortel SNAS 4050 devices in a 
cluster

TCP and UDP

Between Nortel SNAS 4050 and client PC 
(TunnelGuard applet)

SSL/TLS

Between Nortel SNAS 4050 and SREM

SSH

From edge switch to EPM

SNMPv3 Inform

From EPM to edge switch

Telnet over SSH

From authorized endpoint to DHCP server

UDP