Description

This article provides a simple method to scan a given network subnet to list host names and IP addresses all Junos devices present in it. The basic code can be modified easily to perform configuration changes or to collect any required information from those devices using NETCONF over SSH.

Symptoms

  • There may be a large number of Juniper devices in the production environment which need to be inventoried or checked for a certain behavior or configuration consistency.
  • A method was required to discover the Juniper devices in a given subnet and list their host-names using a Python Script.

Solution

One simple way of scanning through a subnet to list the Junos device host names and product models is by implementing the following steps in a Python Script:

  1. Iterate through the hosts in a given subnet using the "ipaddress" Python library.

  2. Connect to Juniper devices using the PyEZ "Device" module". If connection is unsuccessful, print error and move on to next host.

  3. Print the host name. Other details like HW information can also be included if you want.

    Sample code: 

    nw=ipaddress.ip_network('10.85.173.128/25')
for addr in nw:
    dev=Device(host=str(addr),user=####,password=####)
    try:
        dev.open()
    except ConnectError as err:
        print ("Cannot connect to device: {0.EN_US}".format(err))
        continue
    sw=dev.rpc.get_software_information()
    hn=sw.findtext('host-name')
    mod=sw.findtext('product-model')
    print("Hostname of device with IP=", str(addr), "is", str(hn), "Product Model =", str(mod))
    dev.close()

    Sample Script Run: 

    Cannot connect to device: ConnectTimeoutError(10.85.173.128)
Cannot connect to device: ConnectRefusedError(10.85.173.129)
Cannot connect to device: ConnectRefusedError(10.85.173.130)
Cannot connect to device: ConnectRefusedError(10.85.173.131)
Device(10.85.173.132)
Hostname of device with IP= 10.85.173.132 is bacardi Product Model = ex9214
Cannot connect to device: ConnectTimeoutError(10.85.173.133)
Device(10.85.173.134)
Hostname of device with IP= 10.85.173.134 is bacardi Product Model = ex9214
Device(10.85.173.135)
Hostname of device with IP= 10.85.173.135 is m02-17 Product Model = qfx10002-72q
Device(10.85.173.136)
Hostname of device with IP= 10.85.173.136 is m02-19 Product Model = qfx10002-72q
Device(10.85.173.137)
Hostname of device with IP= 10.85.173.137 is m02-21 Product Model = qfx10002-72q

    Python Libraries required: 

    import ipaddress
from ipaddress import ip_network
import jnpr.junos
from jnpr.junos.exception import LockError
from jnpr.junos.exception import ConnectError
from jnpr.junos import Device
import lxml
from lxml import etree
import warnings

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