we have Peplink 710 located at our HQ and 2 Peplink 210 located at 2 sales office at 2 different location. we have 2 ISP line connected to each Peplink 210 for load balancing and failover purpose.
we have upgrade the firmware from v5.3.12 to v5.4.6 for Peplink 210 for location A last week and the upgrade process is successful. everything is working as normal. i have perform the same upgrade for Peplink 210 at location B and this time, 1 ISP line (WAN 2 port) is facing some issues. after upgrade to v5.4.6, WAN 2 ISP line always show as WAN failed DNS test. every 20 second the health check for WAN 2 will return “WAN failed DNS test” message and then reconnect back itself, then after 20 second it will disconnect again and the cycle keeps on going. whenever i reboot the modem/reboot Peplink 210 itself, the WAN 2 connection will remain connected for about 30minutes, after that, the problem is coming back.
we try to ping to 126.96.36.199 using Peplink 210 Ping test and WAN 2 modem ping test at the same time, WAN 2 modem ping test is successful but Peplink 210 ping test is not returning any result. Direct connection from modem to PC is ok, I can browse to any website or ping to any IP.