Hello everyone,
i hope someone can help me here because i been stuck on this for 2 days now and i dont know where else to go.
So basically i am working as a network admin in small government-linked office and we have requirement to integrate with NBI online Appointment portal (National Bureau of Investigation clearance system in Philippines). The system need to communicate with NBI backend for real-time verification of clearance status.
The problem is — we are using Cisco router (ISR 4331) and we configure the network but the API calls to NBI clearance endpoint keep timing out. sometime it work, sometime it just hang. we check the NBI side and they say the problem is on our end.
what i notice is:
ping to the NBI server IP is fine (no packet loss)
but when application try to hit the API endpoint it timeout after 30sec
we check the firewall rules and the port 443 is open
i also try from different machine on same network same issue
i already search alot on Cisco Community before posting here and i found some threads about NBI timeout issue and someone mention it could be related to MTU mismatch or maybe TCP MSS clamping issue on the WAN interface. but i not 100% sure how to check or fix this on ISR 4331.
can anyone guide me on:
how to check if MTU/MSS is causing this issue on Cisco ISR?
any command to troubleshoot this from cisco router side?
is there any known issue with government API portals and cisco routers?
i really appreciate any help. this is blocking a critical process in our office and my manager is putting pressure on me.
sorry for my bad english, i try my best to explain.
Thank you
