OpenWRT uses UCI (/etc/config/snmpd) to generate the /etc/snmp/snmpd.conf , so you cannot simply edit this file and restart snmpd.

翻译:

OpenWRT利用UCI(/etc/config/snmpd)去生成snmp的配置文件/etc/snmp/snmpd.conf,因此你不能简单的编辑此文件,需要重启snmpd进程。

重新启动snmpd进程(./etc/init.d/S50snmpd  restart)后,会保存到配置文件/etc/snmp/snmpd.conf中去。