PHP: snmpwalk - Manual

Description

array snmpwalk ( string hostname, string community, string object_id [, int timeout [, int retries]] )

Returns an array of SNMP object values starting from the object_id as root and FALSE on error.

snmpwalk() function is used to read all the values from an SNMP agent specified by the hostname. Community specifies the read community for that agent. A NULL object_id is taken as the root of the SNMP objects tree and all objects under that tree are returned as an array. If object_id is specified, all the SNMP objects below that object_id are returned.


<?php

$a = snmpwalk("127.0.0.1", "public", ""); 

?>

Above function call would return all the SNMP objects from the SNMP agent running on localhost. One can step through the values with a loop


<?php

foreach ($a as $val) {

    echo "$val\n";

}

?>

snmpwalk

http://mike.eire.ca
23-Mar-2005 10:54


I found on Windows (PHP 5) an empty string did not return anything, it just timed out.  I had to use null instead:



<?php

$a = snmpwalk("127.0.0.1", "public", null);

?>

bobby [dot] clark [at] eku [dot] edu
17-Sep-2003 02:29


I had to use an object_id like these.

'SNMPv2-MIB::system.sysDescr.0'

'IF-MIB::interfaces.ifTable.ifEntry.ifAdminStatus'



<?php

$host = '192.168.1.1';

$community = 'public';

$object_id = 'IF-MIB::interfaces.ifTables.ifEntry.ifAdminStatus';



$sysdesc = snmpwalk($host, $community', $object_id);

print_r($sysdesc);

?>

Lars Troen
14-Mar-2003 03:18


Note that there's different behaviuor in php snmpwalk and ucd snmpwalk. If you try to walk an oid that has one value not under a subkey of the walked oid, ucd snmpwalk will return the value while php's snmpwalk will not.

anders at ei dot nu
29-Jan-2003 10:11


It would be nice to be able to specify what snmp version to use ( 1,2c,3 )



For now, I'ts hardcoded in ext/snmp/snmp.c



change session.version from 1 to 2c or 3 if you need for now..



i.e 



session.version = SNMP_VERSION_1;



to:

session.version = SNMP_VERSION_2c;

steve at ourabode dot org
26-Mar-2002 03:54


Timeout is in MICRO seconds.

1,000,000 &micros = 1 s

layer2 at www dot com
29-Aug-2001 08:52


Something to care about in dealing with snmpwalk:<BR>






While walking the MIB, snmpwalk puts info that gets into an array, and that is correct.<BR>






The trouble happened when snmpwalk needs to collect information from instances that contains subinstances (i.e. walking .1.2.3.4.5 and having instances like 1.1, 1.2, 1.3): in this case it gets info and passes into an array, but when walking the array, each value is preceeded by 'Counter32: '.<BR>






I've tested this in many ways and it always happened the same way.

john at antefacto dot com
17-Aug-2001 08:21


Ah. That's why all of our SNMP stuff was timing out anytime there was any load on the system. Sigh. A waste of two weeks trying to debug snmp....





 Even the snmpcmd manpage doesn't give a


unit for timeout.

billf at freebsd dot org
01-Aug-2001 02:22


for the poster wondering what the


timeout field was measured in:





from the ucd-snmp header file snmp_api.h:





    long    timeout; 


    /* Number of uS until first timeout


    then exponential backoff */

jmartinson(AT_nospam)info234.com
20-Jun-2001 07:41


A quick router device view:





<?


include "header.html";





$host = "auscr1";


$community = "tellme";


                     


$sysDescr = snmpget("$host","$community","system.sysDescr.0");


$ifDescr = snmpwalk("$host","$community","interfaces.ifTable.ifEntry.ifDescr");


$ifIndex = snmpwalk("$host","$community","interfaces.ifTable.ifEntry.ifIndex");


$ifAdminStatus = snmpwalk("$host","$community","interfaces.ifTable.ifEntry.ifAdminStatus");


$ifOperStatus = snmpwalk("$host","$community","interfaces.ifTable.ifEntry.ifOperStatus");


$ifLastChange = snmpwalk("$host","$community","interfaces.ifTable.ifEntry.ifLastChange");


                                          


print "<table border=1 bgcolor=#ffffff><tr><td>$host</td></tr></table><br>";


print "<table border=1 bgcolor=#ffffff><tr><td>$sysDescr</td></tr></table><br>";


print "<table border=1 bgcolor=#ffffff>";


print "<tr> 


        <td>ifIndex</td>


        <td>ifDescr</td>


        <td>ifAdminStatus</td>


        <td>ifOperStatus</td>


        <td>ifLastChange</td>


        </tr>";


             


for ($i=0; $i<count($ifIndex); $i++) {


        print "<tr>";


        print "<td>$ifIndex[$i]</td>";


        print "<td>$ifDescr[$i]</td>";


        print "<td>$ifAdminStatus[$i]</td>";


        print "<td>$ifOperStatus[$i]</td>";


        print "<td>$ifLastChange[$i]</td>";


        print "</tr>";


}            


print "</table>";





?>