A large number of GRE IPIP tunnels in Linux and a drop in speed in the Internet?

Question

linux

Hello!
Faced here with such trabl. There are centos7 there about 50 ipip / gre tunnels and because of this, the speed drops to the outside. I cut off the tunnels, the speed is excellent ... Can anyone help? I've already broken my head. In fact, the same thing was on the juniper. I measure the speed between two linux machines bypassing the tunnel...

Answer 1

Sounds like a last mile or transit provider's trick. They don't particularly favor GRE traffic.

Answer 2

Well, remove the snmp download statistics for all tunnels and see which one is eating the most. One line in the config of routers in other branches (or a central point) can lead to such chaos. Especially in gre, where you can stupidly flood multicast.