(PHP 4, PHP 5)

snmpwalkScarica tutti gli oggetti SNMP da un agente


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.


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.

for ($i=0$i count($a); $i++) {

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User Contributed Notes 9 notes

Lars Troen
14 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.
steve at ourabode dot org
15 years ago
Timeout is in MICRO seconds.
1,000,000 &micros = 1 s
anders at ei dot nu
14 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..


session.version = SNMP_VERSION_1;

session.version = SNMP_VERSION_2c;
layer2 at www dot com
16 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 . 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
16 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.
billf at freebsd dot org
16 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 */
16 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>$sysDescr</td></tr></table><br>";
print "<table border=1 bgcolor=#ffffff>";
print "<tr>
for ($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>";

bobby [dot] clark [at] eku [dot] edu
14 years ago
I had to use an object_id like these.

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

$sysdesc = snmpwalk($host, $community', $object_id);
12 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:

= snmpwalk("", "public", null);
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