Secure Shell (SSH) is a cryptographic network protocol for operating network services securely over an unsecured network. Several application-layer protocols are designed to run over SSH to leverage its security features. STelnet (Secure Telnet) and SFTP (SSH File Transfer Protocol) are direct replacements for their insecure counterparts (Telnet and FTP) and are explicitly built upon the SSH protocol. NETCONF (Network Configuration Protocol) is a network management protocol that uses SSH as its primary transport layer to ensure secure and reliable communication with network devices. DNS, however, operates primarily over UDP or TCP on port 53 and does not use SSH.

A. DNS (Domain Name System) is a protocol for name resolution and does not use SSH for its transport. It typically uses UDP/TCP port 53.

1. Huawei HedEx Documentation

NE40E V800R012C10 Configuration Guide - User Access and Authentication

"SSH Configuration" section. This document describes how SSH provides a security mechanism for protocols like STelnet and SFTP.

2. Huawei HedEx Documentation

NE40E V800R012C10 Configuration Guide - Network Management and Monitoring

"NETCONF Configuration" section

"NETCONF Overview". It states

"NETCONF uses SSH as the transport layer protocol to ensure reliable and secure data transmission."

3. RFC 6241

Network Configuration Protocol (NETCONF)

Section 2.2 "Transport Protocol". It specifies that "NETCONF can be layered over any transport protocol that provides a set of basic requirements. The mandatory transport protocol for NETCONF is SSH."