I was tinkering with my new AC2100 and found out I had some connections drops when using it. I thought it was the WiFi, but using the shell over UART, I found out that the wan link is constantly going down and up again. Here probably some useful logs:
Thu Jul 30 22:13:25 2020 daemon.notice netifd: Network device 'wan' link is down
Thu Jul 30 22:13:25 2020 daemon.notice netifd: Interface 'wan' has link connectivity loss
Thu Jul 30 22:13:25 2020 daemon.notice netifd: Interface 'wan6' has link connectivity loss
Thu Jul 30 22:13:25 2020 kern.info kernel: [ 1269.697353] mt7530 mdio-bus:1f wan: Link is Down
Thu Jul 30 22:13:25 2020 daemon.notice netifd: wan6 (9970): Command failed: Permission denied
Thu Jul 30 22:13:25 2020 daemon.notice netifd: wan (9971): udhcpc: received SIGTERM
Thu Jul 30 22:13:25 2020 daemon.notice netifd: wan (9971): udhcpc: unicasting a release of <ac2100 ip> to <gateway ip>
Thu Jul 30 22:13:25 2020 daemon.notice netifd: wan (9971): udhcpc: sending release
Thu Jul 30 22:13:25 2020 daemon.notice netifd: wan (9971): udhcpc: entering released state
Thu Jul 30 22:13:25 2020 daemon.notice netifd: wan (9971): Command failed: Permission denied
Thu Jul 30 22:13:25 2020 daemon.notice netifd: Interface 'wan' is now down
Thu Jul 30 22:13:25 2020 daemon.debug dnsmasq[2242]: stopped listening on wan(#3): <ac2100 ip> port 53
Thu Jul 30 22:13:25 2020 daemon.warn dnsmasq[2242]: no servers found in /tmp/resolv.conf.d/resolv.conf.auto, will retry
Thu Jul 30 22:13:25 2020 daemon.notice netifd: Interface 'wan6' is now down
Thu Jul 30 22:13:25 2020 daemon.debug dnsmasq[2242]: stopped listening on wan(#3): 2a03:f580:86be:700:8ac3:97ff:fe4f:f066 port 53
[ 1271.745466] mt7530 mdio-bus:1f wan: Link is Up - 100Mbps/Full - flow control rx/tx
Thu Jul 30 22:13:27 2020 daemon.notice netifd: Network device 'wan' link is up
Thu Jul 30 22:13:27 2020 daemon.notice netifd: Interface 'wan' has link connectivity
Thu Jul 30 22:13:27 2020 daemon.notice netifd: Interface 'wan' is setting up now
Thu Jul 30 22:13:27 2020 daemon.notice netifd: Interface 'wan6' has link connectivity
Thu Jul 30 22:13:27 2020 daemon.notice netifd: Interface 'wan6' is setting up now
Thu Jul 30 22:13:27 2020 kern.info kernel: [ 1271.745466] mt7530 mdio-bus:1f wan: Link is Up - 100Mbps/Full - flow control rx/tx
Thu Jul 30 22:13:27 2020 daemon.notice netifd: wan (10205): udhcpc: started, v1.31.1
Thu Jul 30 22:13:27 2020 daemon.notice netifd: wan (10205): udhcpc: sending discover
Thu Jul 30 22:13:27 2020 daemon.notice netifd: wan (10205): udhcpc: sending select for <ac2100 ip>
Thu Jul 30 22:13:27 2020 daemon.notice netifd: wan (10205): udhcpc: lease of <ac2100 ip> obtained, lease time 864000
Thu Jul 30 22:13:28 2020 daemon.debug dnsmasq[2242]: listening on wan(#3): <ac2100 ip> port 53
Thu Jul 30 22:13:28 2020 daemon.notice netifd: Interface 'wan' is now up
Thu Jul 30 22:13:28 2020 daemon.info dnsmasq[2242]: reading /tmp/resolv.conf.d/resolv.conf.auto
Thu Jul 30 22:13:28 2020 daemon.info dnsmasq[2242]: using only locally-known addresses for domain test
Thu Jul 30 22:13:28 2020 daemon.info dnsmasq[2242]: using only locally-known addresses for domain onion
Thu Jul 30 22:13:28 2020 daemon.info dnsmasq[2242]: using only locally-known addresses for domain localhost
Thu Jul 30 22:13:28 2020 daemon.info dnsmasq[2242]: using only locally-known addresses for domain local
Thu Jul 30 22:13:28 2020 daemon.info dnsmasq[2242]: using only locally-known addresses for domain invalid
Thu Jul 30 22:13:28 2020 daemon.info dnsmasq[2242]: using only locally-known addresses for domain bind
Thu Jul 30 22:13:28 2020 daemon.info dnsmasq[2242]: using only locally-known addresses for domain lan
Thu Jul 30 22:13:28 2020 daemon.info dnsmasq[2242]: using nameserver <dns ip>#53
Thu Jul 30 22:13:28 2020 user.notice firewall: Reloading firewall due to ifup of wan (wan)
Thu Jul 30 22:13:31 2020 daemon.notice netifd: Interface 'wan6' is now up
Thu Jul 30 22:13:31 2020 daemon.info dnsmasq[2242]: reading /tmp/resolv.conf.d/resolv.conf.auto
Thu Jul 30 22:13:31 2020 daemon.info dnsmasq[2242]: using only locally-known addresses for domain test
Thu Jul 30 22:13:31 2020 daemon.info dnsmasq[2242]: using only locally-known addresses for domain onion
Thu Jul 30 22:13:31 2020 daemon.info dnsmasq[2242]: using only locally-known addresses for domain localhost
Thu Jul 30 22:13:31 2020 daemon.info dnsmasq[2242]: using only locally-known addresses for domain local
Thu Jul 30 22:13:31 2020 daemon.info dnsmasq[2242]: using only locally-known addresses for domain invalid
Thu Jul 30 22:13:31 2020 daemon.info dnsmasq[2242]: using only locally-known addresses for domain bind
Thu Jul 30 22:13:31 2020 daemon.info dnsmasq[2242]: using only locally-known addresses for domain lan
Thu Jul 30 22:13:31 2020 daemon.info dnsmasq[2242]: using nameserver <dns ip>#53
Thu Jul 30 22:13:31 2020 daemon.info dnsmasq[2242]: using nameserver <dns ipv6>#53
Thu Jul 30 22:13:31 2020 user.notice firewall: Reloading firewall due to ifup of wan6 (wan)
Thu Jul 30 22:13:32 2020 daemon.warn odhcpd[1442]: A default route is present but there is no public prefix on lan thus we don't announce a default route!
Thu Jul 30 22:13:33 2020 daemon.debug dnsmasq[2242]: listening on wan(#3): <ipv6> port 53
I have rebooted the device, performed also a firstboot, but the problem persists.
I also did a sysupgrade with the update available from the 30. july 2020.
Can someone explain me what is happening?
Thank you in advance!