So I recently ran into an issue where I was upgrading Cacti and ran into this issue. I was able to snmpwalk with my credentials and get a response but when I entered those same credentials adding a device to Cacti, there was an SNMP error.
Turns out Cacti is very sensitive to the version of PHP you are using and whether you are using SNMP v2 or v3.
I upgraded PHP to version 5.3.x and all was right with the world for the newer version of Cacti, 0.8.7g
Note: A collegue of mine noticed that Cacti 0.8.7a didn’t work well with PHP 5.3 and he was able to get working with PHP 5.2.x
snmpwalk -v 2c -c community_string IPAddress enterprises.12740.1
snmpwalk -v 2c -c community_string IPAddress enterprises.6876.1
snmpwalk -v 2c -c community_string IPAddress enterprises.674.10892.1
* Juniper: http://kb.juniper.net/InfoCenter/index?page=content&id=KB16545&smlogin=true
1. First make sure the Device is SNMP enabled and has Dell Open Manage installed. Make sure port number 161 protocol udp is open on the firewall.
2. To view the snmp values avaliable:
snmpwalk -v 2c -c CommunityString IPAddress enterprises.674.10892.1
Please edit the -c option to your community string and change the IPAddress to the server’s IP Address.
This should display all Dell Open Manage values available.
NOTE: the 674 is for Dell and the 10892 is for server