SNMP（网络管理协议）

重要提示：为了使用 UCD SNMP 包，需要在编译之前将NO_ZEROLENGTH_COMMUNITY定义为1。 在配置 UCD SNMP 之后，编辑config.h或acconfig.h，查找NO_ZEROLENGTH_COMMUNITY，将 #define 所在行的注释去掉。修改后应该类似这样：

#define NO_ZEROLENGTH_COMMUNITY 1

如果在组合 SNMP 命令时看到奇怪的字段错误，那就是因为没有遵从上述说明。如果不想重新编译 UCD SNMP，可以使用 --enable-ucd-snmp-hack 开关编译 PHP 以绕开上述错误。

Windows 版本在目录mibs中包含了支持 SNMP 的文件。此目录应该移到DRIVE:\usr\mibs，其中 DRIVE 是安装 PHP 所在的盘符，例如c:\usr\mibs。

For my purposes in PHP coding, I have the following SNMP options set, always. These aren't documented very well in PHP's docs, but they make dealing with the SNMP results a LOT easier:
<?php
// Return back the numeric OIDs, instead of text strings.
snmp_set_oid_numeric_print(1);
// Get just the values.
snmp_set_quick_print(TRUE);
// For sequence types, return just the numbers, not the string and numbers.
snmp_set_enum_print(TRUE); 
// Don't let the SNMP library get cute with value interpretation. This makes 
// MAC addresses return the 6 binary bytes, timeticks to return just the integer
// value, and some other things.
snmp_set_valueretrieval(SNMP_VALUE_PLAIN); 
?>

SNMP类

(PHP 5 >= 5.4.0, PHP 7)

SNMP 
{
	/* 属性 */
	public int $max_oids ;
	public int $valueretrieval ;
	public bool $quick_print ;
	public bool $enum_print ;
	public int $oid_output_format ;
	public bool $oid_increasing_check ;
	public int $exceptions_enabled ;
	public array $info ;
	/* 方法 */
	public __construct ( int $version , string $hostname , string $community [, int $timeout = 1000000 [, int $retries = 5 ]] )
	public close ( void ) : bool
	public get ( mixed $object_id [, bool $preserve_keys = FALSE ] ) : mixed
	public getErrno ( void ) : int
	public getError ( void ) : string
	public getnext ( mixed $object_id ) : mixed
	public set ( mixed $object_id , mixed $type , mixed $value ) : bool
	public setSecurity ( string $sec_level [, string $auth_protocol = [, string $auth_passphrase = [, string $priv_protocol = [, string $priv_passphrase = [, string $contextName = [, string $contextEngineID = ]]]]]] ) : bool
	public walk ( string $object_id [, bool $suffix_as_key = FALSE [, int $max_repetitions [, int $non_repeaters ]]] ) : array
	/* 常量 */
	const integer ERRNO_NOERROR = 0 ;
	const integer ERRNO_GENERIC = 2 ;
	const integer ERRNO_TIMEOUT = 4 ;
	const integer ERRNO_ERROR_IN_REPLY = 8 ;
	const integer ERRNO_OID_NOT_INCREASING = 16 ;
	const integer ERRNO_OID_PARSING_ERROR = 32 ;
	const integer ERRNO_MULTIPLE_SET_QUERIES = 64 ;
	const integer ERRNO_ANY = 126 ;
	const integer VERSION_1 = 0 ;
	const integer VERSION_2C = 1 ;
	const integer VERSION_2c = 1 ;
	const integer VERSION_3 = 3 ;
}