mwan3 Recovering from failed interfaces does not work in some cases

[fberndl]

Maintainer: @feckert
Environment: OpenWrt 18.06

Description:
Hi,
I am currently testing mwan3 with two routers with openwrt 18.06 and MWAN3 configured. Both have 3 WAN interfaces configured, between those two routers is an machine which introduces and delay using netem. I want two behavious:

• Failover ( if interface fails, use the next one
• Recover ( if higher prio interface is up then switch traffic to that interface)

The Failover works very good but the recovering works from 4 tries only 2 times. I have behind the routers 2 pc's. The connection between all addresses and interfaces is working fine. I am testing using ping from client to the other one behind the other router( I have no NAT configured, so that works fine, without zones).

• ping reply got stuck on low prio interface
• ping request is using the higher prio interface
• If I stop the ping request (and start it again it switches from the lower prio interface to the higher prio interface.
• I took the rules basicly from the examples (WANA_m1_w2, WANB_m2_w3, WANC_m3_w4) = default_rule

Has anyone the same problem or an idea what the problem could be?

[feckert]

Could it be due to connection tracking?
Have you tried conntrack -F?