tech notes » python

Graphing Alteon configuration

admin — Mon, 31 Aug 2009 22:15:19 +0000

If you happen to use Nortel’s Alteon load balancers and need something to help you visualise your configuration here’s a script that produces graphs of connections and dependencies between groups, virtual IPs, real IPs and services in the Alteon configuration. It’s not very useful, the code is ugly, but the graphs are cool to look at Especially for huge config files with lots of services and VIPs. The script uses two great python libraries – pygraph and graphviz.

Getting all prefixes advertised by an AS

admin — Wed, 22 Jul 2009 21:33:07 +0000

This simple script displays all prefixes advertised by an AS. It uses RIPE’s looking glass to get their local BGP table and parses it for the given AS number.

For example, to get all the other networks advertised by the AS dischaos.com is in, first I need to get Layered tech’s AS number:

whois -h www.ris.ripe.net 216.32.74.94

% This is RIPE NCC’s Routing Information Service
% whois gateway to collected BGP Routing Tables
% IPv4 or IPv6 address to origin prefix match
%
% For more information visit http://www.ripe.net/ris/riswhois.html

route: 216.0.0.0/8
origin: AS3303
descr: SWISSCOM Swisscom (Switzerland) Ltd
lastupd-frst: 2009-06-08 11:31Z 192.65.185.243@rrc04
lastupd-last: 2009-06-08 11:31Z 192.65.185.243@rrc04
seen-at: rrc04
num-rispeers: 1
source: RISWHOIS

route: 216.32.0.0/14
origin: AS3561
descr: SAVVIS – Savvis
lastupd-frst: 2009-06-08 12:56Z 198.32.160.22@rrc11
lastupd-last: 2009-07-22 12:06Z 195.69.145.49@rrc03
seen-at: rrc00,rrc01,rrc03,rrc04,rrc06,rrc07,rrc10,rrc11,rrc12,rrc13,rrc15,rrc16
num-rispeers: 86
source: RISWHOIS

route: 216.32.64.0/19
origin: AS22576
descr: LAYER3-ASN – Layered Technologies, Inc.
lastupd-frst: 2009-06-08 12:56Z 198.32.160.22@rrc11
lastupd-last: 2009-07-22 14:55Z 193.232.244.147@rrc13
seen-at: rrc00,rrc01,rrc03,rrc04,rrc06,rrc07,rrc10,rrc11,rrc12,rrc13,rrc15,rrc16
num-rispeers: 85
source: RISWHOIS

Their AS number is 22576. Now lets see what other networks they advertise:

$ ./getprefixes.py 22576
networks advertised by AS22576:
64.92.160.0/20
72.21.32.0/19
72.36.128.0/17
72.232.0.0/17
72.232.128.0/19
72.232.160.0/21
72.232.168.0/22
72.232.172.0/23
72.232.174.0/23
72.232.176.0/20
72.232.192.0/18
72.233.0.0/19
72.233.28.0/22
72.233.32.0/19
72.233.64.0/18
72.233.64.0/20
72.233.80.0/23
72.233.82.0/23
72.233.84.0/23
72.233.86.0/23
72.233.88.0/21
72.233.96.0/22
72.233.100.0/22
72.233.104.0/21
72.233.112.0/21
72.233.120.0/21
72.233.127.0/24
208.95.152.0/22
209.67.208.0/20
216.32.64.0/19

Nagios plugin template in python

admin — Wed, 29 Apr 2009 08:49:10 +0000

A template for nagios plugins I use:

#!/usr/bin/env python
import sys, getopt
nagios_codes = {‘OK’: 0, 

                ‘WARNING’: 1, 

                ‘CRITICAL’: 2,

                ‘UNKNOWN’: 3,

                ‘DEPENDENT’: 4}
def usage():

    """ returns nagios status UNKNOWN with 

        a one line usage description

        usage() calls nagios_return()

    """

    nagios_return(‘UNKNOWN’, 

            "usage: {0} -h host".format(sys.argv[0]))
def nagios_return(code, response):

    """ prints the response message

        and exits the script with one

        of the defined exit codes

        DOES NOT RETURN 

    """

    print code + ": " + response

    sys.exit(nagios_codes[code])
def check_condition(host):

    """ a dummy check

        doesn’t really check anything 

    """

    return {"code": "OK", "message": host + " ok"}
def main():

    """ example options processing

        here we’re expecting 1 option "-h"

        with a parameter

    """

    if len(sys.argv) < 2:

        usage()
    try:

        opts, args = getopt.getopt(sys.argv[1:], "h:")

    except getopt.GetoptError, err:

        usage()
    for o, value in opts:

        if o == "-h":

            host = value

        else:

            usage()
    result = check_condition(host)

    nagios_return(result[‘code’], result[‘message’])
if __name__ == "__main__":

    main()