snmpwalk

(PHP 4, PHP 5, PHP 7, PHP 8)

snmpwalk — 从代理获取所有 SNMP 对象

说明

snmpwalk(
    string $hostname,
    string $community,
    array|string $object_id,
    int $timeout = -1,
    int $retries = -1
): array|false

snmpwalk() 函数用于从 hostname 指定的 SNMP 代理读取所有值。

参数

hostname

SNMP 代理（服务器）。

community

The read community.

object_id

如果为 null，则将 object_id 作为 SNMP 对象树的根，并且该树下的所有对象都作为数组返回。

如果指定了 object_id，则返回该 object_id 下面的所有 SNMP 对象。

timeout

第一次超时前的微秒数。

retries

发生超时时重试的次数。

返回值

返回从 object_id 开始的 SNMP 对象值数组，如 root 或错误时为 false。

示例

示例 #1 snmpwalk() 示例

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

foreach ($a as $val) {
    echo "$val\n";
}

?>

上面的函数调用将从本地主机上运行的 SNMP 代理返回所有 SNMP 对象。可以通过循环遍历这些值

参见

snmprealwalk() - 返回指定的所有对象，包括它们各自的对象 ID

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User Contributed Notes 9 notes

down

Lars Troen ¶

21 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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anders at ei dot nu ¶

21 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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http://mike.eire.ca ¶

19 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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steve at ourabode dot org ¶

22 years ago


Timeout is in MICRO seconds.
1,000,000 &micros = 1 s

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layer2 at www dot com ¶

23 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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john at antefacto dot com ¶

23 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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billf at freebsd dot org ¶

23 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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jmartinson(AT_nospam)info234.com ¶

23 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

bobby [dot] clark [at] eku [dot] edu ¶

21 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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