How to stop a ICMP attack?

Solution 1:

Contact your ISP and give them this information. They'll need to drop the traffic on the backbone. Once the traffic hits your firewall, the resources are already being consumed on your end. The only way to stop this is to drop it on the backbone.

Solution 2:

These appear to be ICMP Redirects.

These are typically only on a local network segment.

Which IP is yours? 80.227.64.183 > 77.92.136.196: ICMP redirect 94.201.175.188 to host 80.227.64.129

I read (possibly incorrectly) this to say that a gateway on your network segment 80.227.64.183 is telling you (77.92.136.196) to reach 94.201.175.188 via 80.227.64.129??

It looks like there's likely some overlapping VLAN traffic on your network segment. (what do you arp tables look like? arp -an)