Chapter 29: Security
STANDARD Revision 1.0
C4® CMTS Release 8.3 User Guide
© 2016 ARRIS Enterprises LLC. All Rights Reserved.
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SSH-UserAuth Highlights
In the SSH-UserAuth layer, the client user is authenticated with the server using password and/or public key
authentication. The server only supports DSA PEM-formatted and DSA SSH2-formatted (aka, IETF SECSH, IETF RFC-4716,
Standard) user key types. Password authentication is performed by the C4/c CMTS CLI user authentication service, which
includes local password and authentication.
Limitations
The following items should be taken into consideration by C4/c CMTS SSH administrators:
No more than 10 simultaneous sessions can be multiplexed over an SSH connection
No more than 20 simultaneous SSH connections can be handled by the server
The maximum number of Terminal service sessions (interactive CLI and single-command execution) is determined by
the number of enabled VTY lines
With single-command execution, the global and user profiles are not executed like they are during a CLI interactive
session
FTP cannot be tunneled through the Port Forwarding service
All SSH connections are lost when a SCM failure or softswitch occurs.
Server Management
All configurable SSH parameters, including the server public/private keys, are stored in MIBs and the running-config, with
the exception of user public key files. Therefore, the backup/restore procedures for the running-config will cover all SSH
parameters except user public key files. The recommended procedure for user public keys is to keep the master copy of
these files on a separate storage device.
Note: Parameter changes are only picked by the server when it is started. If the changes are made while the server is
running, the server must be restarted to fully effect these changes.
The following types of server activities are logged:
Server control
Key management
Client connectivity
