@Geffers 

Hi Geffers, theoretically, the SPI firewall and IGMP Snooping are enabled by default both. 

IGMP snooping is the process of listening to IGMP (Internet Group Management Protocol) network traffic. The function prevents hosts on a local network from receiving traffic for a multicast group they have not explicitly joined.

SPI firewall is used to prevent cyber attacks and validates the traffic that is passing through the router based on the protocol. 

You can hard reset it and verify whether the two options are enabled by default. 

Good day. 

@pattim 

Hi, May I know the model number of your TP-Link modem?

How about the current hardware and firmware version as well?

The SPI firewall has been enabled by default on the new-released models.

Thank you very much.

@pattim 

Hi, the TD-W9970 V3 is based on the previous platform and did not have separate security settings.

So the SPI  firewall is disabled and the IGMP proxy is enabled under the WAN setup configuration by default;

But Don't worry and there would be no security flaws since a router always offers some protection to LAN from WAN.

Also, They have been improved on the V4 and both IPv4 and IPv6 SPI firewall have been enabled by default;

We would also report this feedback to the senior engineers for further evaluation.

Thank you very much.