Hi,
I have a setup with a RUT241 with Wired WAN + Mobile WAN running. Both are set to Failover. Wired has metric 1 and Mobile has metric 3. Wired WAN seems to be up and running all the time but in the system log it looks like the ping check for Mobile WAN fail and then the Mobile interface is disconnected.
Thu Oct 26 14:31:09 2023 user.info mwan3track[14276]: Check (ping) failed for target "8.8.8.8" on interface mob1s1a1 (qmimux0). Current score: 6
Thu Oct 26 14:31:09 2023 user.notice mwan3track[14276]: Interface mob1s1a1 (qmimux0) is disconnecting
Thu Oct 26 14:31:12 2023 daemon.info dnsmasq[3369]: read /etc/hosts - 4 addresses
Thu Oct 26 14:31:12 2023 daemon.info dnsmasq[3369]: read /tmp/hosts/dhcp.cfg01411c - 2 addresses
Thu Oct 26 14:31:12 2023 daemon.info dnsmasq-dhcp[3369]: read /etc/ethers - 0 addresses
Thu Oct 26 14:31:22 2023 user.notice mwan3track[14276]: Interface mob1s1a1 (qmimux0) is connecting
Thu Oct 26 14:31:25 2023 daemon.info dnsmasq[3369]: read /etc/hosts - 4 addresses
Thu Oct 26 14:31:25 2023 daemon.info dnsmasq[3369]: read /tmp/hosts/dhcp.cfg01411c - 2 addresses
Thu Oct 26 14:31:25 2023 daemon.info dnsmasq-dhcp[3369]: read /etc/ethers - 0 addresses
Thu Oct 26 14:31:25 2023 user.info mwan3track[14276]: Lost 1 ping(s) on interface mob1s1a1 (qmimux0). Current score: 5
Thu Oct 26 14:32:13 2023 daemon.warn dnsmasq[3369]: possible DNS-rebind attack detected: device-local-e73bad03-48f6-43a0-9a80-ccb7f7f544b4.remotewd.com
Thu Oct 26 14:33:39 2023 user.info mwan3track[14276]: Check (ping) failed for target "8.8.8.8" on interface mob1s1a1 (qmimux0). Current score: 6
Thu Oct 26 14:33:39 2023 user.notice mwan3track[14276]: Interface mob1s1a1 (qmimux0) is disconnecting
Thu Oct 26 14:33:42 2023 daemon.info dnsmasq[3369]: read /etc/hosts - 4 addresses
Thu Oct 26 14:33:42 2023 daemon.info dnsmasq[3369]: read /tmp/hosts/dhcp.cfg01411c - 2 addresses
Thu Oct 26 14:33:42 2023 daemon.info dnsmasq-dhcp[3369]: read /etc/ethers - 0 addresses
Thu Oct 26 14:33:53 2023 user.notice mwan3track[14276]: Interface mob1s1a1 (qmimux0) is connecting
Thu Oct 26 14:33:56 2023 daemon.info dnsmasq[3369]: read /etc/hosts - 4 addresses
Thu Oct 26 14:33:56 2023 daemon.info dnsmasq[3369]: read /tmp/hosts/dhcp.cfg01411c - 2 addresses
Thu Oct 26 14:33:56 2023 daemon.info dnsmasq-dhcp[3369]: read /etc/ethers - 0 addresses
Thu Oct 26 14:33:56 2023 user.info mwan3track[14276]: Lost 1 ping(s) on interface mob1s1a1 (qmimux0). Current score: 5
Thu Oct 26 14:37:40 2023 daemon.warn dnsmasq[3369]: possible DNS-rebind attack detected: -8h9.now-dns.net
Thu Oct 26 14:39:02 2023 user.info mwan3track[14276]: Check (ping) failed for target "8.8.8.8" on interface mob1s1a1 (qmimux0). Current score: 6
Thu Oct 26 14:39:02 2023 user.notice mwan3track[14276]: Interface mob1s1a1 (qmimux0) is disconnecting
Thu Oct 26 14:39:05 2023 daemon.info dnsmasq[3369]: read /etc/hosts - 4 addresses
Thu Oct 26 14:39:05 2023 daemon.info dnsmasq[3369]: read /tmp/hosts/dhcp.cfg01411c - 2 addresses
Thu Oct 26 14:39:05 2023 daemon.info dnsmasq-dhcp[3369]: read /etc/ethers - 0 addresses
Thu Oct 26 14:39:16 2023 user.notice mwan3track[14276]: Interface mob1s1a1 (qmimux0) is connecting
Thu Oct 26 14:39:19 2023 daemon.info dnsmasq[3369]: read /etc/hosts - 4 addresses
Thu Oct 26 14:39:19 2023 daemon.info dnsmasq[3369]: read /tmp/hosts/dhcp.cfg01411c - 2 addresses
Thu Oct 26 14:39:19 2023 daemon.info dnsmasq-dhcp[3369]: read /etc/ethers - 0 addresses
Thu Oct 26 14:39:19 2023 user.info mwan3track[14276]: Lost 1 ping(s) on interface mob1s1a1 (qmimux0). Current score: 5
The RUT241 has a Wireguard connection running and all internet traffic (both in and out) is supposed to pass through this connection.
I can’t understand why the mobile interface is going down that often? Is it because of the failed ping? If so, why does the ping fail?
I’m greatful for any help I can get on this 
The RUT241 is running software version RUT2M_R_00.07.05
Br,
Henrik