树莓派部署DietPi后SSH访问被拒绝问题求助

Hey there! Let's work through this SSH problem step by step—these are the most common checks and fixes to get you connected:

1. Verify DietPi's Network & IP Address #

• First, confirm your DietPi device is actually connected to the network:
  • Hook up a monitor to your Raspberry Pi; the initial boot screen should display the assigned IP address.
  • Alternatively, log into your router's admin panel and look for a device named dietpi in the connected devices list.
  • On a Linux machine, scan your local network with arp-scan -l to find the Raspberry Pi's MAC address (typically starts with B8:27:EB or DC:A6:32) and its corresponding IP. On Windows, use arp -a in Command Prompt.

2. Ensure SSH Service is Running on DietPi #

DietPi enables SSH by default, but it never hurts to confirm:

• If you have a monitor attached, log in with the default credentials (root / dietpi) and run:

  systemctl status sshd
  

• If the service isn't active, start it with:

  systemctl start sshd
  

• To make it start automatically on boot:

  systemctl enable sshd
  

• Also, check if you completed the initial DietPi setup wizard—sometimes SSH isn't fully available until you walk through the first-time configuration (timezone, user setup, etc.).

3. Check Firewall Settings #

• On DietPi: By default, the firewall is disabled, but verify with ufw status. If it's active, allow SSH traffic:

  ufw allow ssh
  

• On Windows Client: Check Windows Defender Firewall to ensure it's not blocking outbound connections on port 22.
• On Linux Gateway: Confirm the gateway's firewall allows SSH traffic between your Windows client and DietPi. Use iptables -L or ufw status to review rules, and add an allow rule if needed.

4. Validate SSH Client Configuration #

• Double-check the IP address you're entering in PuTTY/Bitvise—make sure it's the DietPi device's IP, not your gateway or another device.
• Confirm the port is set to 22 (DietPi's default). If you changed it during setup, check the value in /etc/ssh/sshd_config on DietPi.
• In PuTTY, ensure you've selected SSH as the connection type (not Telnet or Raw).

5. Confirm Credentials Are Correct #

• Even though you're using the default root / dietpi, double-check for typos (Caps Lock is a common culprit!). Remember, PuTTY doesn't display characters when entering the password.
• If you suspect the password was changed during setup, log in via monitor and reset it with:

  passwd root
  

6. Troubleshoot the Linux Gateway Setup #

Since you're using a Linux server as a gateway, rule out routing issues:

• Verify the gateway has proper routes to forward traffic between your Windows client's network and DietPi's network. Run ip route to check the routing table.
• Ensure IP forwarding is enabled on the gateway:

  cat /proc/sys/net/ipv4/ip_forward
  

  If the output is 0, enable it temporarily with:

  echo 1 > /proc/sys/net/ipv4/ip_forward
  

  To make it permanent, edit /etc/sysctl.conf and set net.ipv4.ip_forward=1, then run sysctl -p.
• Test connecting directly without the gateway (connect Windows and DietPi to the same local network) to isolate if the gateway is the bottleneck.

内容的提问来源于stack exchange，提问作者Victor