通過snmp獲取設備每個介面的配置IP地址，網段信息和VLAN介面號

第一部分，觀察通過snmp OID能獲取的信息，對信息進行關聯。

1、通過 snmp獲取到介面IP地址和掩碼信息，發現IP地址作為索引值；

2、每個IP地址的索引，都可以關聯到介面的索引

3、每個介面索引，都可以通過snmp獲取到介面的名稱，

降這個3個數據進行關聯，可以得到介面名稱和網段信息的關聯。

第二部分：通過代碼實現。

get_vlan_network.py

import re,os,ipaddress


#get the interface Vlan value
def get_Vlanif_value(host,SNMP_community):


    vlan_dict = {}
    pattern = re.compile(r'(\d+)\s*=\s*STRING:\s*(\S+)')


    cmd = "snmpwalk -v 2c -c " + SNMP_community  +" "+ host + " ifname | grep Vlan" # 進行過濾，僅顯示VLAN介面
    tmp = os.popen(cmd).readlines()
    # print("begin:",tmp)


    for i in tmp:
        matches = re.search(pattern, i)


        if matches:
            if_id = matches.group(1) #if_id: interface_snmp_ID
            Vlan_value = re.search(r'\d+', matches.group(2)).group()
            # print(if_id,Vlan_value)
            vlan_dict[if_id] = Vlan_value
   
    return vlan_dict



# VLAN = get_Vlan_value(host)
# print(VLAN)



# get the interface ip address and inetface snmp ID
def get_if_ip(host,SNMP_community):


    if_dict = {}
    pattern = r'(\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}) = INTEGER: (\d+)'


    cmd = "snmpwalk -v 2c -c " + SNMP_community +" "+ host + " .1.3.6.1.2.1.4.20.1.2"
    tmp = os.popen(cmd).readlines()


    for i in tmp:
        matches = re.search(pattern, i)


        if matches:
            ip_address = matches.group(1)
            if_id = matches.group(2)
            if_dict[ip_address] = if_id


    return if_dict


# IF_value = get_if_ip(host)
# print(IF_value)



def get_network_value(host,SNMP_community):
   
    network_dict = {}
    pattern = r'(\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}) = IpAddress: (\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})'


    cmd = "snmpwalk -v 2c -c " + SNMP_community +" " + host + " .1.3.6.1.2.1.4.20.1.3 | grep -wv -e 255.255.255.255"
    tmp = os.popen(cmd).readlines()


    for i in tmp:
        matches = re.search(pattern, i)


        if matches:
            ip_address = matches.group(1)
            subnet_mask = matches.group(2)
            network_str = f"{ip_address}/{subnet_mask}"
            network = ipaddress.IPv4Network(network_str, strict=False)


            network_dict[ip_address] = network.with_prefixlen
   
    return network_dict



def get_network_subnet_Vlan(host,SNMP_community):
    # 將網段信息與VLAN ID進行關聯


    Netowrk_Vlan ={}
    Vlan_info = get_Vlanif_value(host, SNMP_community)
    If_info =  get_if_ip(host, SNMP_community)
    Network_info = get_network_value(host, SNMP_community)
   
    # print(host,SNMP_community)


    for k ,v_net in Network_info.items():
        # print(k)
        if k in If_info:
            # Netowrk_Vlan[v_net]
            if If_info[k] in Vlan_info: #Vlan_info 進行了過濾，
                # print( v_net, Vlan_info[If_info[k]])
                Netowrk_Vlan[v_net]=Vlan_info[If_info[k]]


    return Netowrk_Vlan



if __name__ == '__main__':


   
    with open('host_snmp.txt', 'r', encoding='utf8') as f:
       
        for line in f:
            dict = {}
            host = line.split(" ")[0]
            snmp_community = (line.split(" ")[1]).strip()
             
            # print(host,snmp_community)
            #將所有數據放入字典
            dict[host] = get_network_subnet_Vlan(host,snmp_community)   
            print(dict)