Depending on your IOS version, you could use control plane policing to drop SNMP packets bound for the device. This would not affect packet switching, and would not hinder performance like an interface ACL. Here is an example:
access-list 113 deny udp 10.1.1.1 any eq 161
access-list 113 permit udp any any eq 161
access-list 114 deny ip any any
class-map match-all matchsnmp
match access-group 113
policy-map dropsnmp
class matchsnmp
drop
control-plane
service-policy input dropsnmp
This would allow SNMP from 10.1.1.1, but deny it from any other host. Other traffic bound for this device would be permitted.
