snmpget

When I try to get a 64 bit counter variable (e.g. ifHCInOctets) using snmpget function, following error message was appeared.Error in packet: (noSuchName) There is no such variable name in this MIBThe solution for this is to use snmp2_get(); function. The prameters are same as snmpget();

It seems that for each snmpget() its own socket() will be opened. This is not closed after snmpget() finishes. Neither existing sockets are reused by subsequent snmpget() calls.When querying a few switches with lots of ports the maximum file descriptor count of Apache is exhausted. Thus no more snmpget() are possible. Additionaly no more files can be read by this particular Apache process. Neither the PHP file, any include files nor any other files (like a .css file, ...).This probably explains the observation of tkjode at phalnet dot com. Different to his case is that I'm using Linux.

This function can be used to identify devices on a network, by getting their sysObjectID and sysDescr. On short, this is what I did:<?php   $sysid = @snmpget($ip, 'public', '.1.3.6.1.2.1.1.2.0', 300);   if($sysid) {      $sysdescr = @snmpget($ip, 'public', '.1.3.6.1.2.1.1.1.0', 300);   }?>What I get for equipments, for example:<?php   $sysid = 'OID: .iso.3.6.1.4.1.5003.8.1.1.57';// => AudioCodes MP114;   //.iso.3.6.1.4.1. is a "prefix" for the OID domain   //5003 is the IANA number for AudioCodes   //8.1.1.57 identifies the equipment type (MP-114)   $sysdescr = '"Product: MP-114 FXS;SW Version: 5.00A.024"';?>Unfortunately, not all of them report correct objectID, for example they report only the vendor and stop there etc.In case you are wondering why I used the code '.1.3.6.1.2.1.1.2.0' in the function call instead of "sysObjectID.0", it's because only numeric codes seem to work on Windows. For more codes, google "cisco SNMP Object Navigator".Have fun.

The online documentation says that the function returns "FALSE" on error but, actually, it returns NULL on error.

For those wishing to use v2 or 3you can consult the php_snmp.h headerhere is the list of functionsPHP_FUNCTION(snmpget);PHP_FUNCTION(snmpgetnext);PHP_FUNCTION(snmpwalk);PHP_FUNCTION(snmprealwalk);PHP_FUNCTION(snmp_get_quick_print);PHP_FUNCTION(snmp_set_quick_print);PHP_FUNCTION(snmp_set_enum_print);PHP_FUNCTION(snmp_set_oid_output_format);PHP_FUNCTION(snmpset);PHP_FUNCTION(snmp2_get);PHP_FUNCTION(snmp2_getnext);PHP_FUNCTION(snmp2_walk);PHP_FUNCTION(snmp2_real_walk);PHP_FUNCTION(snmp2_set);PHP_FUNCTION(snmp3_get);PHP_FUNCTION(snmp3_getnext);PHP_FUNCTION(snmp3_walk);PHP_FUNCTION(snmp3_real_walk);PHP_FUNCTION(snmp3_set);PHP_FUNCTION(snmp_set_valueretrieval);PHP_FUNCTION(snmp_get_valueretrieval);

Some SNMP agents return mac addresses as hex encoded ascii.e.g. '30:30:3a:31:37:3a:66:32:3a:39:62:3a:34:36:3a:30:65'Each octet represents 4 bits of the mac address.Some vendors may also encode the separators into the string.Heres a function to convert these strings back into plain hex.<?php$hexStr = '30:30:3a:31:37:3a:66:32:3a:39:62:3a:34:36:3a:30:65';echo(str_replace(':','',hexStr2Ascii($hexStr)));function hexStr2Ascii($hexStr,$separator = ':'){    $hexStrArr = explode($separator,$hexStr);    $asciiOut = null;    foreach($hexStrArr as $octet){        $asciiOut .= chr(hexdec($octet));    }    return $asciiOut;}?>Outputs: '0017f29b460e'

I have no idea what the timeout value is, but 1 second is really really 1 000 000 000 nano seconds (cf. http://en.wikipedia.org/wiki/SI_prefix).

Unfortunately, It appears that you can not put multiple objects into the snmpget function, ie: sysUpTime.0 ifInOctets.1 ifOutOctets.1.  For what it's worth, the time argument is in nano-seconds as previously mentioned.  There is a lot of conflicting information out there about this.

2 year tidbit update :)<?php// author: dstjohn at mediacast1.com// updated: 09-11-2005// set some vars$snmpcommunity = 'PUBLIC'; //snmp community name$ips = 'test1.com,test2.com'; //ips or dns to get snmp data from$system_number = '1';//end da vars//start da loop d loopfor ($i = 0; $i <= $system_number; $i++) {$sysip = explode(",",$ips);//get system name$sysname[0] = snmpget($sysip[$i], $snmpcommunity, "sysName.0");$sysname[1] = eregi_replace("STRING:","",$sysname[0]);echo 'System Name: '.$sysname[1].'<br>';//system description$sysdesc[0] = snmpget($sysip[$i], $snmpcommunity, "sysDescr.0");$sysdesc[1] = eregi_replace("STRING:","",$sysdesc[0]);echo 'System Description: '.$sysdesc[1].'<br>';//system location$sysloc[0] = snmpget($sysip[$i], $snmpcommunity, "sysLocation.0");$sysloc[1] = eregi_replace("STRING:","",$sysloc[0]);echo 'System Location: '.$sysloc[1].'<br>';//current tcp connections$tcpcons[0] = snmpget($sysip[$i], $snmpcommunity, "tcpCurrEstab.0");$tcpcons[1] = eregi_replace("Gauge32:","",$tcpcons[0]);echo 'Open TCP/IP Connections: '.$tcpcons[1].'<br>';//get system uptime$sysuptime[0] = snmpget($sysip[$i], $snmpcommunity, "system.sysUpTime.0");$sysuptime[1] = eregi_replace("Timeticks:","",$sysuptime[0]);echo 'System Uptime: Timeticks -'.$sysuptime[1].'<br>';//windows only//installed memoryif(eregi('Windows',$sysdesc[1])){$mem[0] = snmpget($sysip[$i], $snmpcommunity, "HOST-RESOURCES-MIB::hrMemorySize.0");$mem[1] = eregi_replace("INTEGER:","",$mem[0]);$mem[2] = eregi_replace("KBytes","",$mem[1]);echo 'Insalled Memory: '.$mem[2].' KiloBytes<br>';}echo '<br><br>';}//end loop?>

pooling a cisco.$ip = '1.1.1.1';$community ='publico';$a = snmpget($ip,$community, "IF-MIB::ifLastChange.1")$b = snmpget($ip,$community, "IF-MIB::ifAlias.1");print("a = ".$a."\n"."b = ".$b."\n");a = Timeticks: (929969969) 107 days, 15:14:59.69b = Timeticks: (929969969) 107 days, 15:14:59.69when the interface has not description.

It has been observed on NT/2000 systems that flooding devices with SNMP requests will cause NT's SNMP service to stop working.For example, I polled 183 switches on our network just fine.  I then attempted to simulate heavy traffic to that page by refreshing and breaking connections (as any real world system would have to go through).  SNMP stopped working throughout the entire machine, including non-PHP/Webserver processes.

It looks like you can use a non-standard port for SNMP
with something like this:

$foo = snmpwalk('foo.bar.com:1161', 'foofoo', '.1.3.6');

This is on PHP 3.16; I haven't managed to get PHP 4.02 to compile successfully on Solaris 2.6 yet.
--Michael

According the SNMPv2-MIB DEFINITIONS the right syntax should be "system.sysContact.0" and NOT "system.SysContact.0" as used in the above example 2251. SNMPv2-MIB DEFINITIONS ... sysContact OBJECT-TYPE SYNTAX DisplayString (SIZE (0..255)) MAX-ACCESS read-write STATUS current DESCRIPTION "The textual identification of the contact person for this managed node, together with information on how to contact this person. If no contact information is known, the value is the zero-length string." ::= { system 4 }

The timeout is in micro seconds. Thus 1.000.000 means 1 Second.

Little tidbit for snmpget function<?php//snmpget system stats$host = 'localhost';$community = 'public';//get system name$sysname = snmpget($host, $community, "system.sysName.0");//get system uptime$sysup = snmpget($host, $community, "system.sysUpTime.0");$sysupre = eregi_replace("([0-9]{3})","",$sysup);$sysupre2 = eregi_replace("Timeticks:","",$sysupre);$sysupre3 = eregi_replace("[()]","",$sysupre2);//get tcp connections$tcpcon = snmpget($host, $community,"tcp.tcpCurrEstab.0");$tcpconre = eregi_replace("Gauge32:","",$tcpcon);echo 'System Name: '.$sysname.'<br>System Uptime: '.$sysupre3.'<br>Current Tcp Connections: '.$tcpconre.'<br>';?>

The default value of Timeout is 1000000  nanoseconde (1 sec) and the retrie is 5 thsi value is set by Net-SNMP library.#!/usr/local/bin/php<?php $time_start = microtime(true); $reponse = snmpget('10.5.1.1', 'public', "1.3.6.1.2.1.1.3.0",1000000,5); $time_end = microtime(true); $time = $time_end - $time_start; echo "Delay in $time secondes\n";?>