Hi JamesMMatthews You have done really much research. I just say something I know, maybe have some help. 1. The IGMP report/leave message will be only forwarded to route port. Route port is the port...

I got a ER6020 and did the test with the software of nmap, did not find the open port of 161. Maybe you can post your screenshot to show us the detail.

Maybe you can find their Hotline Support.

As Mitya said, after configured the deny ACL rule, we still need to configure a ACL rule to allow all traffic. Because V3 has the black list. Otherwise, all traffic cannot pass.

Hi, You can try to reset your switch and clear the cache of your browser. I also see that TP-Link releaes the new firmware for TL-SG1016DE V3 20180629. You can have a try.

I think this SNMP feature is only used for LAN and we cannot access through WAN port. I listened that ER6020 may release the new firmware soon. Maybe you can have a try at that time.