snmpwalk

(PHP 4, PHP 5)

snmpwalkScarica tutti gli oggetti SNMP da un agente

Descrizione

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

La funzione restituisce un array con i valori degli oggetti SNMP utilizzando object_id come punto di partenza, oppure FALSE se si verifica un errore.

La funzione snmpwalk() viene utilizzata per leggere tutti i valori dall'agente SNMP specificato nel parametro hostname. Il parametro Community specifica la comunitĂ  per l'agente. Con l'impostazione a NULL del parametro object_id si indica la radice dell'albero degli oggetti SNMP, pertanto saranno restituiti nell'array tutti gli oggetti dell'albero. Viceversa se si indica un valore per object_id, sarranno restituiti tutti gli oggetti sottostanti object_id.

<?php
$a 
snmpwalk("127.0.0.1""public""");
?>

L'esempio precedente mostra come recuperare tutti gli oggetti SNMP dall'agente attivo sulla macchina locale. Tramite un loop (illustrato di seguito) si può accedere a tutti i valori.

<?php
for ($i=0$i count($a); $i++) {
    echo 
$a[$i];
}
?>

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User Contributed Notes 9 notes

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2
Lars Troen
11 years ago
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.
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1
http://mike.eire.ca
9 years ago
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);
?>
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1
anders at ei dot nu
11 years ago
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;
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0
bobby [dot] clark [at] eku [dot] edu
10 years ago
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);
?>
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0
layer2 at www dot com
12 years ago
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.
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0
john at antefacto dot com
12 years ago
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.
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0
billf at freebsd dot org
12 years ago
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 */
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0
jmartinson(AT_nospam)info234.com
13 years ago
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>";

?>
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-1
steve at ourabode dot org
12 years ago
Timeout is in MICRO seconds.
1,000,000 &micros = 1 s
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