Hướng dẫn php snmpset

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

snmpset — Set the value of an SNMP object

Description

snmpset(
    string $hostname,
    string $community,
    array|string $object_id,
    array|string $type,
    array|string $value,
    int $timeout = -1,
    int $retries = -1
): bool

Parameters

The hostname of the SNMP agent (server).

The write community.

The SNMP object id.

The MIB defines the type of each object id. It has to be specified as a single character from the below list.

If OPAQUE_SPECIAL_TYPES was defined while compiling the SNMP library, the following are also valid:

Most of these will use the obvious corresponding ASN.1 type. 's', 'x', 'd' and 'b' are all different ways of specifying an OCTET STRING value, and the 'u' unsigned type is also used for handling Gauge32 values.

If the MIB-Files are loaded by into the MIB Tree with "snmp_read_mib" or by specifying it in the libsnmp config, '=' may be used as the type parameter for all object ids as the type can then be automatically read from the MIB.

Note that there are two ways to set a variable of the type BITS like e.g. "SYNTAX BITS {telnet(0), ftp(1), http(2), icmp(3), snmp(4), ssh(5), https(6)}":

• Using type "b" and a list of bit numbers. This method is not recommended since GET query for the same OID would return e.g. 0xF8.
• Using type "x" and a hex number but without(!) the usual "0x" prefix.

See examples section for more details.

The new value.

The number of microseconds until the first timeout.

The number of times to retry if timeouts occur.

Return Values

Returns true on success or false on failure.

If the SNMP host rejects the data type, an E_WARNING message like "Warning: Error in packet. Reason: (badValue) The value given has the wrong type or length." is shown. If an unknown or invalid OID is specified the warning probably reads "Could not add variable".

Examples

Example #1 Using snmpset()

  snmpset("localhost", "public", "IF-MIB::ifAlias.3", "s", "foo");
?>

Example #2 Using snmpset() for setting BITS SNMP object id

  snmpset("localhost", "public", 'FOO-MIB::bar.42', 'b', '0 1 2 3 4');
// or
  snmpset("localhost", "public", 'FOO-MIB::bar.42', 'x', 'F0');
?>

ch at lathspell dot de ¶

12 years ago

Note that there are two ways to set a variable of the type BITS like e.g.:
  SYNTAX        BITS {telnet(0), ftp(1), http(2), icmp(3), snmp(4), ssh(5), https(6)}

1. Using type "b" and a list of bit numbers like:
  snmpset('FOO-MIB::bar.42', 'b', '0 1 2 3 4');
with the disadvantage that the success is not easily verifyable as an snmpget() for the same OID would return e.g. 0xF8.

2. Using type "x" and a hex number but without(!) the usual "0x" prefix:
  snmpset('FOO-MIB::bar.42', 'x', 'F0');

slawrance at technologist dot com ¶

23 years ago

The "type" parameter must be one of the following, depending on the type of variable to set on the SNMP host:

i    INTEGER
u    unsigned INTEGER
t    TIMETICKS
a    IPADDRESS
o    OBJID
s    STRING
x    HEX STRING
d    DECIMAL STRING
n    NULLOBJ
b    BITS

If OPAQUE_SPECIAL_TYPES was defined while compiling the SNMP library, the
following are also valid:

U    unsigned int64
I    signed int64
F    float
D    double

As an example, using "i" would set an integer, and "s" would set a string.  If the SNMP host rejects the data type, you might get the following message: "Warning: Error in packet. Reason: (badValue) The value given has the wrong type or length."

If you specify an unknown or invalid OID, you might get a "Could not add variable" message.  When specifying an absolute OID (one that is already resolved) that is completely numeric, prepend it with a period.  For example, an OID that could enable/disable Ethernet ports on an Asante hub might be "1.3.6.1.2.1.22.1.3.1.1.3.6.4.0", but you would need to use ".1.3.6.1.2.1.22.1.3.1.1.3.6.4.0" in the OID parameter so that the SNMP library won't try to resolve an already resolved OID.  Friendly, unresolved OIDs do not need the period prepended, such as "system.SysContact.0"

tridman ¶

15 years ago

If you have importet the MIB-Files into the MIB Tree with "snmp_read_mib" you may use '=' as the "type" parameter.
In this case the type will also be taken from the loaded mib file. (Octest strings will be interpreted like strings though)
Comes in handy for a more dynamic use of snmpset.