1280 MTU can it be upgraded?


I have a private network using cloudflared, to this network i connected a device that serves some functionality in a UDP port. And i have finally a windows client with WARP Client trying to access that hardware IP and its UDP port.

I have connectivity, however when connecting via UDP to my device using WARP im seeing the following error in my tunnel

error udp Failed to send session payload from destination to transport
“origin UDP payload has 1388 bytes, which exceeds transport MTU 1280”

My windows client shows:
MTU MediaSenseState Bytes In Bytes Out Interface

1280 1 238431 391511 CloudflareWARP
1460 1 1352161336 1400547911 Ethernet

Unfortunately i cannot change the payload size in my device

Is it there any possibility to increase the MTU for my tunnel/warp client?

1 Like

Yup. The case for OpenVPN or IPsec tunnels is that they’ll use more of the available link MTU. I understand this limit is just imposed by the Warp client, so seems to me that making the choice a policy issue is the right approach. Here in Blighty, do not expect to exceed physical MTU of 1432, and have UDP-based applications that would benefit from that increase. Please make it possible!