snmpwalk
(PHP 4, PHP 5)
snmpwalk — Fetch all the SNMP objects from an agent
Описание
$hostname
, string $community
, string $object_id
[, int $timeout = 1000000
[, int $retries = 5
]] )
snmpwalk() function is used to read all the values from
an SNMP agent specified by the hostname.
Список параметров
-
hostname -
The SNMP agent (server).
-
community -
The read community.
-
object_id -
If
NULL,object_idis taken as the root of the SNMP objects tree and all objects under that tree are returned as an array.If
object_idis specified, all the SNMP objects below thatobject_idare returned. -
timeout -
The number of microseconds until the first timeout.
-
retries -
The number of times to retry if timeouts occur.
Возвращаемые значения
Returns an array of SNMP object values starting from the
object_id as root or FALSE on error.
Примеры
Пример #1 snmpwalk() Example
<?php
$a = snmpwalk("127.0.0.1", "public", "");
foreach ($a as $val) {
echo "$val\n";
}
?>
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
Смотрите также
- snmprealwalk() - Return all objects including their respective object ID within the specified one
- snmp_get_quick_print
- snmp_get_valueretrieval
- snmp_read_mib
- snmp_set_enum_print
- snmp_set_oid_numeric_print
- snmp_set_oid_output_format
- snmp_set_quick_print
- snmp_set_valueretrieval
- snmp2_get
- snmp2_getnext
- snmp2_real_walk
- snmp2_set
- snmp2_walk
- snmp3_get
- snmp3_getnext
- snmp3_real_walk
- snmp3_set
- snmp3_walk
- snmpget
- snmpgetnext
- snmprealwalk
- snmpset
- snmpwalk
- snmpwalkoid
Коментарии
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>";
?>
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 */
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.
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.
Timeout is in MICRO seconds.1,000,000 µs = 1 s
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;
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.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);
?>
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);
?>