Ubuntu LTS 系統下的 Crontab 任務排程入門

from datetime import datetime

print(datetime.now())
print("你好，世界！")

* * * * * command

* * * * * /usr/bin/python3 /path/to/your/script/print_hello_friend.py >> /path/to/your/log/cron.log

import subprocess
import datetime

def ping_ip(ip_address):
    try:
        result = subprocess.run(['ping', '-c', '3', ip_address], capture_output=True, text=True, check=True)
        return f"{ip_address} is reachable. \n{result.stdout}"
    except subprocess.CalledProcessError as e:
        return f"{ip_address} is unreachable. \n{e.stderr}"

with open("/path/to/your/ip_list.txt", "r") as f:
    ip_addresses = f.readlines()

with open("/path/to/your/log/ping_log.txt", "a") as log_file:
    log_file.write(f"--- {datetime.datetime.now()} ---\n")
    for ip in ip_addresses:
        ip = ip.strip()
        log_file.write(ping_ip(ip) + "\n")

from pysnmp.hlapi import *

def snmp_get(ip, community, oid):
    errorIndication, errorStatus, errorIndex, varBinds = next(
        getCmd(SnmpEngine(),
               CommunityData(community),
               UdpTransportTarget((ip, 161)),
               ContextData(),
               ObjectType(ObjectIdentity(oid)))
    )

    if errorIndication:
        print(errorIndication)
    elif errorStatus:
        print('%s at %s' % (errorStatus.prettyPrint(),
                            errorIndex and varBinds[int(errorIndex) - 1][0] or '?'))
    else:
        for varBind in varBinds:
            print(' = '.join([x.prettyPrint() for x in varBind]))

snmp_get('192.168.1.1', 'public', '1.3.6.1.2.1.1.1.0') # 查詢系統描述

from pysnmp.hlapi import *

def snmpv3_get(target, oid, user, auth_protocol, auth_key, privacy_protocol, privacy_key):
    engine = SnmpEngine()
    usm_user = UsmUserData(user, auth_key, privacy_key,
                           authProtocol=auth_protocol,
                           privProtocol=privacy_protocol)
    target = UdpTransportTarget((target, 161))
    context = ContextData()

    errorIndication, errorStatus, errorIndex, varBinds = next(
        getCmd(engine, usm_user, target, context, ObjectType(ObjectIdentity(oid)))
    )

    if errorIndication:
        print(f"錯誤：{errorIndication}")
    elif errorStatus:
        print(f"錯誤：{errorStatus.prettyPrint()} at {errorIndex and varBinds[int(errorIndex) - 1][0] or '?'}")
    else:
        for name, val in varBinds:
            print(f"{name.prettyPrint()} = {val.prettyPrint()}")


# 使用範例：
#  auth_protocol: usmHMACMD5AuthProtocol, usmHMACSHAAuthProtocol, usmHMAC128SHA224AuthProtocol, usmHMAC192SHA256AuthProtocol, usmHMAC256SHA384AuthProtocol, usmHMAC384SHA512AuthProtocol, usmNoAuthProtocol
#  privacy_protocol: usmDESPrivProtocol, usm3DESEDEPrivProtocol, usmAesCfb128Protocol, usmAesCfb192Protocol, usmAesCfb256Protocol, usmNoPrivProtocol

snmpv3_get("192.168.1.1", "1.3.6.1.2.1.1.1.0", "myuser", usmHMACMD5AuthProtocol, "authkey123", usmDESPrivProtocol, "privkey456")

from pysnmp.hlapi import *

auth_protocol = usmHMACMD5AuthProtocol
auth_key = "your_auth_key"
priv_protocol = usmDESPrivProtocol
priv_key = "your_priv_key"

target = UdpTransportTarget(("your_device_ip", 161))
oid = ObjectIdentity("1.3.6.1.2.1.1.3.0")  # 系統啟動時間

errorIndication, errorStatus, errorIndex, varBinds = next(
    getCmd(
        SnmpEngine(),
        UsmUserData("your_user", auth_key, priv_key, authProtocol=auth_protocol, privProtocol=priv_protocol),
        target,
        ContextData(),
        ObjectType(oid),
    )
)

if errorIndication:
    print(errorIndication)
elif errorStatus:
    print(f"{errorStatus.prettyPrint()} at {errorIndex and varBinds[int(errorIndex) - 1][0] or '?'}")
else:
    for varBind in varBinds:
        print(f"{varBind[0].prettyPrint()} = {varBind[1].prettyPrint()}")

sudo dnf install -y net-snmp net-snmp-utils net-snmp-devel

sudo systemctl stop snmpd  # 務必停止服務
sudo net-snmp-create-v3-user SNMPUser1 # 建立使用者 SNMPUser1
# 根據提示設定驗證和隱私密碼

sudo vi /var/lib/net-snmp/snmpd.conf # 新增以下設定
createUser SNMPUser1 MD5 "AUTHPass1" AES "PRIVPass1"

sudo vi /etc/snmp/snmpd.conf  # 新增以下設定
rwuser SNMPUser1

sudo systemctl start snmpd  # 啟動服務
sudo systemctl status snmpd  # 檢查服務狀態

snmpwalk -v3 -u SNMPUser1 -l authPriv -a MD5 -A AUTHPass1 -X PRIVPass1 localhost

snmpwalk -v3 -u SNMPUser1 -l authPriv -a MD5 -A AUTHPass1 -X PRIVPass1 127.0.0.1

from netmiko import ConnectHandler

def configure_snmpv3(device, username, auth_password, priv_password):
    """設定 Cisco 裝置的 SNMPv3."""

    config_commands = [
        f"snmp-server user {username} auth md5 {auth_password} priv aes 128 {priv_password}",
        "snmp-server group v3group v3 auth priv",
        "snmp-server view v3view iso included",
        f"snmp-server community public RO v3group", # 僅供測試，實際環境中應移除或使用更安全的設定
        "snmp-server host 192.168.1.10 version 3 auth priv v3group v3view" #  Fedora 伺服器的IP
    ]

    with ConnectHandler(**device) as connection:
        connection.send_config_set(config_commands)

# 裝置連線資訊
r2 = {
    "device_type": "cisco_ios",
    "host": "192.168.127.22",  # R2 的 IP 地址
    "username": "jdoe",
    "password": "cisco",
}

configure_snmpv3(r2, "SNMPUser1", "AUTHPass1", "PRIVPass1")

# 編輯 /etc/ssh/ssh_config 檔案
sudo vi /etc/ssh/ssh_config

# 在檔案中加入以下一行，允許更多金鑰交換演算法
KexAlgorithms +diffie-hellman-group1-sha1,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1

# 在 Cisco 裝置上執行以下指令
crypto key generate rsa

Host *
    KexAlgorithms +diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1
    HostkeyAlgorithms +ssh-rsa

R2(config)#crypto key generate rsa
...
R2(config)#ip ssh version 2

import paramiko
from getpass import getpass

def test_ssh_login(hostname, username, password):
    try:
        ssh_client = paramiko.SSHClient()
        ssh_client.set_missing_host_key_policy(paramiko.AutoAddPolicy())
        ssh_client.connect(hostname, username=username, password=password, timeout=5)
        print(f"SSH login to {hostname} successful.")
        stdin, stdout, stderr = ssh_client.exec_command("show clock")
        output = stdout.read().decode("utf-8")
        print(f"\nTime on {hostname}:\n{output}")
        print("-" * 79)
    except paramiko.AuthenticationException:
        print("Authentication failed. Please check your username and password.")
    except paramiko.SSHException as e:
        print(f"Error: Unable to establish SSH connection to {hostname}. Details: {str(e)}")
    finally:
        ssh_client.close()

if __name__ == "__main__":
    file_path = 'ip_addresses.txt'
    try:
        with open(file_path, 'r') as file:
            ip_addresses = file.read().splitlines()
    except FileNotFoundError:
        print(f"Error: File '{file_path}' not found.")
        exit()
    username = input("Enter the username: ")
    password = getpass("Enter the password: ")
    for ip in ip_addresses:
        test_ssh_login(ip, username, password)

from snmp_helper import snmp_set_oid, snmp_get_oid_v3, snmp_extract

def configure_snmpv3(ip, user, auth_key, priv_key, engine_id):
    """設定 Cisco 裝置的 SNMPv3 引數。"""

    # 設定 SNMPv3 使用者
    snmp_set_oid(ip, '1.3.6.1.6.3.15.1.2.2.1.1.1', user, snmp_credentials=(user, auth_key, priv_key, engine_id))

    # 設定認證和加密演算法
    snmp_set_oid(ip, '1.3.6.1.6.3.10.1.1.3', 'usmHMACSHAAuthProtocol', snmp_credentials=(user, auth_key, priv_key, engine_id))
    snmp_set_oid(ip, '1.3.6.1.6.3.10.1.1.6', 'usmAESPrivProtocol', snmp_credentials=(user, auth_key, priv_key, engine_id))

    # 驗證設定
    snmp_v3_data = snmp_get_oid_v3(ip, '1.3.6.1.2.1.1.5.0', snmp_credentials=(user, auth_key, priv_key, engine_id))
    device_name = snmp_extract(snmp_v3_data)
    print(f"裝置名稱: {device_name}")


# 範例用法
ip = '192.168.1.1'
user = 'myuser'
auth_key = 'authkey123'
priv_key = 'privkey456'
engine_id = '80000002010987654321'

configure_snmpv3(ip, user, auth_key, priv_key, engine_id)