SNMP Community Strings Explained: public, private and SNMPv3 for Network+
An SNMP community string is the password that SNMP versions 1 and 2c use to control access to a device's management data. Calling it a password is generous: it is sent in cleartext, it is shared rather than per-user, and the default values are known to everyone. A community string is a shared secret that is neither secret nor protected. SNMPv1 and v2c have no real authentication, and that is the whole exam point. The Two Kinds Read-only (RO). Permits GET operations — reading interface counters, CPU load, uptime, system description. The default value is almost universally public . Read-write (RW). Permits SET operations as well, which means changing device configuration . The default is almost universally private . Those two default values are worth memorizing exactly, because exam questions use them and because they are the first thing any attacker tries. A device left on defaults with RW enabled can be reconfigured by anyone who can reach it. Why This Is So Dangerou...