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Parse, Audit, Query, Build, and Modify Cisco IOS-style configurations

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Introduction: What is ciscoconfparse?

ciscoconfparse parses, audits, queries, builds, and modifies Cisco IOS configurations.

Usage: A contrived config audit

Suppose you have a large switched network and need to run audits on your configurations; assume you need to build configurations which conform to the following criteria:

  • Access switchports must be configured with storm-control
  • Trunk ports must not have port-security
  • Timestamps must be enabled on logging and debug messages

You should follow the following steps.

  1. Assume that you start with the following Cisco IOS configuration saved as short.conf (All the interfaces need to be changed, to correctly conform):

    interface FastEthernet0/1
     switchport mode access
     switchport access vlan 532
    interface FastEthernet0/2
     switchport mode trunk
     switchport trunk allowed 300,532
     switchport nonegotiate
     switchport port-security maximum 2
     switchport port-security violation restrict
     switchport port-security
    interface FastEthernet0/3
     switchport mode access
     switchport access vlan 300
  2. Next, we build this script to read and change the config:

    from ciscoconfparse import CiscoConfParse
    def standardize_intfs(parse):
        ## Search all switch interfaces and modify them
        # r'^interface.+?thernet' is a regular expression, for ethernet intfs
        for intf in parse.find_objects(r'^interface.+?thernet'):
            has_stormcontrol = intf.has_child_with(r' storm-control broadcast')
            is_switchport_access = intf.has_child_with(r'switchport mode access')
            is_switchport_trunk = intf.has_child_with(r'switchport mode trunk')
            ## Add missing features
            if is_switchport_access and (not has_stormcontrol):
                intf.append_to_family(' storm-control action trap')
                intf.append_to_family(' storm-control broadcast level 0.4 0.3')
            ## Remove dot1q trunk misconfiguration...
            elif is_switchport_trunk:
    ## Parse the config
    parse = CiscoConfParse('short.conf')
    ## Add a new switchport at the bottom of the config...
    parse.append_line('interface FastEthernet0/4')
    parse.append_line(' switchport')
    parse.append_line(' switchport mode access')
    parse.commit()     # commit() **must** be called before searching again
    ## Search and standardize the interfaces...
    parse.commit()     # commit() **must** be called before searching again
    ## I'm illustrating regular expression usage in has_line_with()
    if not parse.has_line_with(r'^service\stimestamp'):
        ## prepend_line() adds a line at the top of the configuration
        parse.prepend_line('service timestamps debug datetime msec localtime show-timezone')
        parse.prepend_line('service timestamps log datetime msec localtime show-timezone')
    ## Write the new configuration

Normally, regular expressions should be used in .has_child_with(); however, you can technically get away with the bare strings that I used in standardize_intfs() in some cases. That said, regular expressions are more powerful, and reliable when searching text. Usage of the has_line_with() and find_objects() methods illustrate regular expression syntax.

  1. After the script runs, the new configuration ( looks like this:

    service timestamps log datetime msec localtime show-timezone
    service timestamps debug datetime msec localtime show-timezone
    interface FastEthernet0/1
     switchport mode access
     switchport access vlan 532
     storm-control broadcast level 0.4 0.3
     storm-control action trap
    interface FastEthernet0/2
     switchport mode trunk
     switchport trunk allowed 300,532
     switchport nonegotiate
    interface FastEthernet0/3
     switchport mode access
     switchport access vlan 300
     storm-control broadcast level 0.4 0.3
     storm-control action trap
    interface FastEthernet0/4
     switchport mode access
     storm-control broadcast level 0.4 0.3
     storm-control action trap

The script:

  • Added a switchport named FastEthernet0/4
  • Added storm-control to Fa0/1, Fa0/3, and Fa0/4
  • Removed port-security from Fa0/2
  • Added timestamps to logs and debug messages


The latest copy of the docs are archived on the web


ciscoconfparse needs Python versions 2.6, 2.7 or 3.2+; the OS should not matter. If you want to run it under a Python virtualenv, it’s been heavily tested in that environment as well.

Installation and Downloads

The best way to get ciscoconfparse is with setuptools or pip. If you already have setuptools, you can install as usual:

# Substitute whatever ciscoconfparse version you like...
easy_install -U ciscoconfparse==1.0.1

Alternatively you can install with pip:

pip install ciscoconfparse

Otherwise download it from PyPi, extract it and run the script:

python install

If you’re interested in the source, you can always pull from the github repo or bitbucket repo:

  • From bitbucket:

    hg init
    hg clone
  • From github:

    git clone git://

License and Copyright

ciscoconfparse is licensed GPLv3; Copyright David Michael Pennington, 2007-2014.

The ipaddr module is distributed with ciscoconfparse to facilitate unit tests. ipaddr uses the ASF License 2.0; ipaddr is part of the Python standard library, starting in Python 3.3.


  1. QUESTION: I want to use ciscoconfparse with Python3; is that safe? ANSWER: As long as you’re using Python 3.2 or higher, it’s safe. I test every release against Python 3.2+.
  2. QUESTION: The example in this README.rst file looks different than what I’m used to seeing. Did you change something? ANSWER: Yes, starting around ciscoconfparse v0.9.10 I introducted more methods directly on IOSConfigLine objects; going forward, these methods are the preferred way to use ciscoconfparse, although the sphinx docs on my website haven’t been updated yet. Please start using the new methods shown in the example, since they’re faster, and you type much less code this way. Eventually I’m going to deprecate the original style ciscoconfparse methods, but that’s not going to happen yet.
  3. QUESTION: ciscoconfparse saved me a lot of time, I want to give money. Do you have a donation link? ANSWER: I love getting emails like this; helping people get their jobs done is why I wrote the module. However, I’m not accepting donations.
  4. QUESTION: Is there a way to use this module with perl? ANSWER: Yes, I do this myself. Install the python package as you normally would and import it into perl with and Inline::Python from CPAN.
  5. QUESTION: When I use find_children("interface GigabitEthernet3/2"), I’m getting all interfaces beginning with 3/2, including 3/21, 3/22, 3/23 and 3/24. How can I limit my results? ANSWER: There are two ways… the simplest is to use the ‘exactmatch’ option… find_children("interface GigabitEthernet3/2", exactmatch=True). Another way is to utilize regex expansion that is native to many methods… find_children("interface GigabitEthernet3/2$")

Other Resources

Bug Tracker and Support

ciscoconfparse Support

Please report any suggestions, bug reports, or annoyances with ciscoconfparse through the bitbucket bug tracker.

Python Support

If you’re having problems with general python issues, consider searching for a solution on Stack Overflow. If you can’t find a solution for your problem or need more help, you can ask a question.

Cisco Support

If you’re having problems with your Cisco devices, you can open a case with Cisco TAC; if you prefer crowd-sourcing, you can ask on the Stack Exchange Network Engineering site.


ciscoconfparse is developed with mercurial, and pushed to bitbucket. hg-git keeps github repo and bitbucket in sync, so it shouldn’t matter if you just want to fork the github repo.


I use the Travis CI project to continuously test ciscoconfparse on Python versions 2.6 through 3.3.

Click the image below for details; the current build status is:

Travis CI Status

Author and Thanks

ciscoconfparse was written by David Michael Pennington (mike [~at~] pennington [/dot] net).

Special thanks:

  • Thanks to David Muir Sharnoff for his suggestion about making a special case for IOS banners.
  • Thanks to Alan Cownie for his API suggestions.
  • Sola Dei Gloria.

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