Community String Name Limitations
Some network equipment vendors use special characters in their SNMP community strings to indicate different elements of data that should be queried.
For example: Cisco uses the “@” symbol to specify VLAN numbers that should be queried with an SNMP query. They call this “Community String Indexing”.
Other vendors may use different symbols in different ways to limit/focus SNMP queries from a device (like to specify a specific VRF for example).
As a result, it is strongly advised to not use symbols in SNMPv2c community strings, as they may be mis-interpreted by the device.Device-specific limitations should be researched with the device manufacturer.