堡垒机连接错误

import paramiko

# 堡垒机配置
bastion_host = 'bastion.example.com'
bastion_port = 22
bastion_username = 'user'
bastion_password = 'password'

# 目标设备配置
target_host = 'target.example.com'
target_port = 22

# 创建SSH客户端
ssh_client = paramiko.SSHClient()
ssh_client.set_missing_host_key_policy(paramiko.AutoAddPolicy())

try:
    # 连接堡垒机
    ssh_client.connect(bastion_host, port=bastion_port, username=bastion_username, password=bastion_password)
    
    # 创建新的SSH会话通过堡垒机连接到目标设备
    transport = ssh_client.get_transport()
    dest_addr = (target_host, target_port)
    local_addr = ('localhost', 22)
    channel = transport.open_channel("direct-tcpip", dest_addr, local_addr)
    
    # 连接目标设备
    target_ssh_client = paramiko.SSHClient()
    target_ssh_client.set_missing_host_key_policy(paramiko.AutoAddPolicy())
    target_ssh_client.connect(target_host, port=target_port, sock=channel)
    
    # 执行命令
    stdin, stdout, stderr = target_ssh_client.exec_command('ls -l')
    print(stdout.read().decode())
    
except paramiko.AuthenticationException as e:
    print(f"Authentication failed: {e}")
except paramiko.SSHException as e:
    print(f"SSH connection failed: {e}")
finally:
    ssh_client.close()
    if 'target_ssh_client' in locals():
        target_ssh_client.close()