2025-02-28 0

Locking Down Access: Step-by-Step SSH Configuration on Huawei S7700 Series Switches

When a European bank failed an audit due to Telnet usage on their S7706 switches, the remediation cost hit €230,000—a price tag that could have been avoided with proper SSH implementation. In an era where 63% of network breaches originate from unencrypted management channels (per 2023 Cisco Cybersecurity Report), mastering SSH on Huawei’s S7700 series isn’t optional. This guide walks through battle-tested SSH hardening techniques, from RSA key generation to role-based access controls.

1. Why SSH Trumps Telnet for S7700 Management

1.1 Cryptographic Safeguards

  • AES-256 Encryption: Mitigates packet sniffing risks in shared DC environments
  • Public-Key Authentication: Eliminates password spraying attacks (SSHv2 only)
  • Session Integrity: HMAC-SHA2 prevents command injection via man-in-the-middle

1.2 Compliance Drivers

  • GDPR Article 32: Mandates encryption for admin access to EU data processors
  • NIST SP 800-131A: Requires 3072-bit RSA keys post-2023

2. Core SSH Configuration Workflow

systemctl status sshd

2.1 Initial Setup

# Generate RSA host keys (3072-bit)  
<HUAWEI> system-view  
[HUAWEI] rsa local-key-pair create  
Key name: Host-Key  
Key modulus (1024-4096): 3072  

# Enable SSH service  
[HUAWEI] ssh server enable  
[HUAWEI] ssh server compatible-ssh1x disable  

# Configure VTY for SSH-only access  
[HUAWEI] user-interface vty 0 4  
[HUAWEI-ui-vty0-4] authentication-mode aaa  
[HUAWEI-ui-vty0-4] protocol inbound ssh

2.2 AAA Authentication

# Create admin role with privilege level 15  
[HUAWEI] role name Network-Admin  
[HUAWEI-role-Network-Admin] rule 1 permit command all  

# Add local user with certificate-based access  
[HUAWEI] aaa  
[HUAWEI-aaa] local-user admin ssh-certificate  
[HUAWEI-aaa] local-user admin service-type ssh  
[HUAWEI-aaa] local-user admin role Network-Admin

3. Advanced Hardening Techniques

3.1 Session Timeout Controls

# Set idle timeout to 10 minutes  
[HUAWEI-ui-vty0-4] idle-timeout 10 0  

# Limit concurrent sessions  
[HUAWEI] ssh server max-sessions 5

3.2 Logging & Auditing

# Enable SSH event logging  
[HUAWEI] info-center enable  
[HUAWEI] ssh server log enable  
[HUAWEI] ssh user admin audit enable  

# Export logs to syslog server  
[HUAWEI] info-center loghost 192.168.1.10 facility local6

4. Troubleshooting SSH Connectivity

4.1 Diagnostic Commands

# Verify SSH service status  
[HUAWEI] display ssh server status  

# Check active sessions  
[HUAWEI] display ssh user-information  

# Debug failed attempts  
[HUAWEI] terminal monitor  
[HUAWEI] debug ssh all

4.2 Common Pitfalls

  • Key Mismatch: Ensure client’s OpenSSH version supports SHA2 RSA signatures
  • Port Blocking: Verify ACLs allow TCP/22 inbound

SSH on the S7700 isn’t just about encryption—it’s about constructing an impregnable command fortress. After implementing these measures, a Singaporean university reduced unauthorized access attempts by 89%. As cybersecurity architect Mei-Ling Zhou advises: “Treat SSH like your network’s DNA—unique, complex, and impossible to replicate.”